Kobi: Structuring New Approaches In Bicycle Helmet Design by Dustin Bailey

Kobi: Structuring New Approaches in Bicycle Helmet Design. Dustin Bailey

Kobi

Kobi: Structuring New Approaches in Bicycle Helmet Design.

Dustin Bailey

Contents

Acknowledgments

Project Abstract

Brain & Bicycle: An Introduction

Structured Impacts Mapping a Skull Wrapping a Skull Simplifying Ingredients The Unattended The Shape of Prints to Come 117

Understanding The Helmet A Helmet That Falls for a City Challenging Conventions With Robots Methods & Approach Summary 29

Minds Behind Helmets: Field & Research

Structuring New Approaches: Research & Development

Sum of All Parts: Project Outcomes Kobi: The Helmet Research Futures

151

Humans, Robots & Helmets: A Conclusion Conflicted Relationships The Urban Cyclist Breaking the Mould Ways of Working Outcomes & Significance

Literature Review The Space Between Identifying Oversights 161

Appendix Photo Study: Locked Helmets Image Index Glossary of Terms

168

Bibliography

Acknowledgments

It never ceases to amaze me how many people end up influencing and assisting with the development of a project. This is especially true in terms of this year long project. I need to start by thanking Liam Fennessy for the constant guidance as my supervisor, and for being able to push me to challenge what I think I know. Thank you Dr. Soumitri Varadarajan for revealing not only effective ways of writing, but the joy which can be found in the process. I would also like to thank Dr. Scott Mason, Martin Leary, Sophie Gaur, Din Heagney, Kate Archdeacon, James Whitta and my fellow classmates. Dustin Bailey

Abstract

Although the purpose of bicycle helmets is easily understood, many cyclists perceive them to be a nuisance. Everyday experiences that accompany wearing a helmet can often subdue the value of its intended safety function. Reviewing the developmental history of the helmet reveals a largely linear and conventional evolution. This raises the question: how can the design of bicycle helmets be readdressed in order to alter cyclistsâ&#x20AC;&#x2122; perceptions of helmets? Expanded polystyrene foam has come to define the majority of helmets on the market today. Although it has been established as a standard, its characteristics impose certain limitations on the design of the object. With technology such as three-dimensional scanning and printing becoming more accessible, there are opportunities to research alternative methods of designing and manufacturing helmets. By combining an emphasis on understanding the behaviours and needs of urban cyclists with the potential of new manufacturing processes, this project uncovers avenues for divergence within helmet design. Experimental material tests uncover the performance capabilities of additively manufactured structures, while the fit and functional components of helmets are explored to propose how new technologies and processes can complement one another. In a country such as Australia, where it is mandatory for all cyclists to wear helmets, the helmet significantly influences how a person experiences the act of cycling. By challenging the conventions within helmet design, this research sheds light on how new technology could be utilised, and attempts to more positively influence the relationships cyclists have with their helmets.

Brain & Bicycle: An Introduction

Understanding The Helmet

The bicycle helmet has evolved with a simple intention; help protect a cyclists brain if they crash. The problem with the helmet however, is that cyclists spend most of their time wearing it in situations when they are perfectly safe, and not crashing. It is only within the few and unlikely short number of seconds that some cyclists experience the scenario in which the helmet was designed for. When this is combined with the fact that wearing a sculpted block of foam upon ones head is not very visually attractive, it comes as no surprise that helmets are not warmly welcomed into every individualâ&#x20AC;&#x2122;s cycling practices. It seems to be a rather large commitment in behaviour for little tangible gain. This should not however dismiss the value in bicycle helmets when a cyclist does experience a crash. It instead reveals an area of opportunity within bicycle helmet design; bicycle helmets which are designed for cycling, not just for crashing. There is a much larger range of activities and behaviours which exist within the decision to wear a helmet. This project aims to progress the perceptions of value in bicycle helmets by considering the broad number of activities both on and off the bicycle.

Brain & Bicycle: An Introduction

â&#x20AC;&#x2DC; This project analyses a deeper and much more complicated issue. Why do the people who are so reluctant to wear helmets dislike helmets so muchâ&#x20AC;&#x2122;? There is a relentless debate which argues over whether or not bicycle helmets truly reduce head injury. This is a maddening question as there are just as many sources which scientifically validate the efficacy of bicycle helmets as there are sources which state the exact opposite. In realistic terms, no one will definitively be able to confirm this either way since the intricacies of contributing elements elusively conceal any one outcome. This project takes a firm viewpoint on this matter and is due primarily to the location in which the project will be developed. This project studies Melbourne Victoria in Australia. The debate over the efficacy of helmets in preventing injury is less relevant in a city which has mandatory helmet legislation. If the aim of the project were to discover effective methods of reversing helmet legislation, with the view that helmets are ineffective, then this project would entertain the debate. This however is not the case. Instead, this project analyses a deeper and much more complicated issue. Why do the people who are so reluctant to wear helmets dislike helmets so much, and how could the helmet be redesigned to diminish or remove this distaste?

Brain & Bicycle: An Introduction

â&#x20AC;&#x2DC; There is not one helmet to suit all scenarios, and it would be extremely difficult to attempt to design oneâ&#x20AC;&#x2122;

Cycling cannot be reduced solely down to the act of pedalling a bicycle to move somewhere. There are a diverse range of cyclist types and cultures which exhibit their own types of behaviours, environments and motivations for cycling. This is also true about the variety of needs within bicycle helmets. A person who wears a helmet for short rides experiences cycling in a very different way than a cyclist who wears a helmet for several hours. Commuting to work is a very different activity than riding a bicycle to meet friends in the park. Within each type of cyclist, there exists varied levels of ability for their cycling culture to accommodate the desire to wear a helmet. This quickly reveals the need for the diverse range of helmets on the market today. There is not one helmet to suit all scenarios, and it would be extremely difficult to attempt to design one. This project targets the substantial but perhaps overlooked group of urban cyclists in order to effectively focus the outcomes of this research.

Brain & Bicycle: An Introduction

A Helmet That Falls for A City

When thinking about cycling within different cities around the world, it is impossible to assume that all cyclists have the same requirements. This project focuses specifically on the City of Melbourne and its urban cyclists. The distances cyclists in Melbourne travel, the weather they cycle in, the types of accidents they are prone to and the infrastructure available all contribute to the specific behaviours these cyclists have. By designing a helmet specifically for this cityâ&#x20AC;&#x2122;s context, it gives an opportunity for bicycle helmet research to translate directly into the artefact, something which current helmet design could benefit from. The range of helmets currently on the market are largely driven by competitive road cycling, off road mountain biking or have adopted helmets which are used for other extreme sports such as skateboarding. These helmets have been developed through influences which are specific to needs which often differ from a city cyclist. This project will instead allow the design development to look beyond the limited scope of aerodynamics or styling, and reassess how a helmet should serve an urban cyclist from the ground up.

Brain & Bicycle: An Introduction

Challenging Conventions With Robots

Throughout a rather short history, helmet manufacturers have made significant technological advances within helmet design. The helmets on the market today are dramatically improved compared to the helmets of previous decades. It should be made clear however that the main reason that these improvements are so impressive is less to do with the true advantages they offer cyclists. It is instead impressive because helmet design has reached such high levels of refinement while operating within an extremely limited scope in terms of actual design exploration. This is a result of a standard material which is used in almost all helmets on the market; expanded polystyrene foam (EPS). While this material has become a standard, new and advanced manufacturing techniques continue to emerge within other industries. Additive manufacturing has been rapidly developing and is pushing many fields to rethink how an object is produced. This project views the technical requirements of helmets such as impact absorption, size or fit, and weight as possible characteristics which align themselves well for the effective use of additive manufacturing. The overall goal in exploring these processes will be to agitate the current conventions in bicycle helmet design and manufacture.

Brain & Bicycle: An Introduction

â&#x20AC;&#x2DC; The ability to produce one off items freely, without overhead costs of tooling and production, allows the project to consider custom fit helmetsâ&#x20AC;&#x2122; It should be made very clear that additive manufacturing is not a universally viable process. It is often a culprit of misrepresented enthusiasm within media. Although it is amazing in terms of facilitating new opportunities for designers and manufacturers, the process has certain limitations not unlike any other manufacturing technique. However, in terms of manufacturing a bicycle helmet, there are several aspects of the process which could compliment the object. The ability to produce one off items freely, without overhead costs of tooling and production allows the project to consider custom fit helmets. The process also accommodates complexity in structure and geometry in ways which traditional moulding methods are incapable of producing. While these new opportunities are explored, the process also forces the project to work within a set of limitations. These limits are actively addressed in order to understand inventive ways of designing with and for the process, as opposed to merely hoping the project can be effectively produced through additive manufacturing.

Brain & Bicycle: An Introduction

Methods & Approach

The project has been separated into two distinct phases based on individual narratives. Each phase consists of a specific set of activities which are explored through various methods and approaches. The first phase of the project investigates human behaviour and the relationship cyclists have with their helmets. Extensive observation of urban cyclists within Melbourne uncovers the intricacy of events cyclists experience while wearing a helmet. Photo documentation of how helmets are worn, stored and transported have highlighted several oversights within current helmet design. Personal experiences as an avid cyclist, combined with expert interviews within the cycling community, go beyond the visible and further inform where interventions can be made. As a whole, this phase of the project defines whatâ&#x20AC;&#x2122;s beneath the helmet, specifically people, and how the helmet could more competently serve the individuals who are wearing them. The second phase of the project is built around the new technologies designers have access to, and how they may be used to open new avenues within helmet design. This is a heavily experimental part of the project and seeks to generate new knowledge through action and engagement as research. Two key technologies are explored. The first is 3D scanning. This is a technology which has been around for many years, but has only recently become more accessible.

Brain & Bicycle: An Introduction

With a focus on improving the fit of helmets, 3D scanning allows individual skull shapes to be mapped and translated into precise digital models to design around. The project uncovers the benefits and limitations of the technology through experimentation, and is a fundamental component of the project. 3D printing or additive manufacturing sits at the core of the project. It is another technology which is rapidly developing within industry but still remains slightly ambiguous in terms of effective application beyond prototyping. The project acknowledges the specific characteristics of the process and has developed methods of working with them. Both the advantages and the constraints inform the project as each stage progresses. Through activities such as material testing, prototyping and user testing, a highly hands on approach validates each step of the design development. The activities undertaken within the project exist within the fields of research as opposed to refined or market ready product design. The direct intentions within the project are to experiment and comprehend how this new technology could begin to address the oversights which may lead to a reluctance to wear bicycle helmets. The final artefacts produced act as a method of communicating several research outcomes within a condensed set of objects. The immediate viability and efficacy of these objects remain to be seen, and instead act as stepping stones which may lead to further research. Collaboration with fields outside of industrial design would allow these concepts to be further validated and refined. In order to extend the outcomes of the project, future scenarios are documented as a way of proposing how these processes and concepts might be implemented in the near future.

Brain & Bicycle: An Introduction

Summary

Throughout the research of the project there have been numerous considerations regarding how the bicycle helmet could be improved. The driving motivation behind these developments is to improve a cyclistâ&#x20AC;&#x2122;s relationship with their helmet. This project addresses that what people experience while wearing a helmet extends far beyond the rare event of crashing. In an attempt to increase the perception of value in the helmet, aspects such as comfort are deeply considered. Through 3D scanning individual skull shapes, custom fit helmets can begin to serve cyclists on a much more personal level. As a result, the artefact has the opportunity to reduce its bulk, since size generalisations are not compensated for through excessive padding. The size and look of the object become important considerations as image can be of great concern to people while enjoying the act of cycling. Beyond the fit and style of the object, specific functions relating to the needs of urban cyclists are also included. The simple ability to leave a helmet locked securely to a bicycle is something current helmets do not necessarily consider. This project has discovered this to be a significant advantage as it means a cyclist does not have to carry the helmet with them throughout their day.

Brain & Bicycle: An Introduction

This project proposes that the existing development of bicycle helmets remains rather stagnant. Expanded polystyrene is a material commonly used within bicycle helmets, and it defines the majority of helmets on the market today. It is however only one material. Through research and experimentation this project begins to shed light on how additive manufacturing could be seen as an alternative, and can be used in a comprehensive manner to produce a bicycle helmet. This process allows the helmet to be completely reimagined in terms of structure and features. The projects outcomes address considerations such as sustainability to a much higher degree than currently present. 3D printing has allowed the helmet to develop as a singular object as opposed to being constructed of several separate material components. Fasteners for straps and padding along with infinite internal structures are all produced within the same material process. Durability and lifespan have also been considered in order to withstand the less forgiving environment of the city. 3D printing has also influenced the functional aspects of the helmet. Design details often share functionality in relation to both the user wearing the helmet, and the helmet being manufactured.

Brain & Bicycle: An Introduction

â&#x20AC;&#x2DC; This project begins to shed light on how additive manufacturing could be used in a comprehensive manner to produce a bicycle helmetâ&#x20AC;&#x2122; As opposed to positioning the project as a standalone body of research, it instead concludes by outlining a series of scenarios or propositions. These propositions begin to perceive how the combination of these ideas may be implemented, or further explored. The physical helmet produced within this research can only be viewed as a single journey and is in no way a definitive outcome. Through reflection of the different challenges and findings within this research, propositions on immediate areas of continued investigation have been outlined. These areas are diverse and span across aspects such as scientific material testing, ability to comply with safety standards, efficient or automated 3D model generation and materials capable of multiple impacts. The following chapters document the project through its individual stages of research, design development, outcomes and conclusions.

Brain & Bicycle: An Introduction

Activities

Phase

ap p Re i n g ad i Re n g fle c Pl t ing an n G i ng oa l Re S et t ad i n g i Re n g fe re Sy nci nt ng h I m esis m i ng e Ph r s i n ot g o W g ra rit ph in in g Cr g ea ti Fo ng r m Na r Fr ing rat i am Hy ve p s i W ng oth rit es in is Ph g ot o A g ra na ph ly in C o si n g g m p Co a r i n nc g e W ptu rit a i n l isi ng D g ig ita 3D l M P r o de Ex int i ll in pe n g g rim en t in g

Project Phase Timeline

Weeks 01 02

Establish Field of Enquiry

03 04 05 06

Research Field & Establish A Gap

07 08 09

Develop Propositions

10 11 12 13

Expand Propositions Through Experimentation

at e

r ia oc l Te u s 3D me t ing nt Sc i n A ann g na ly i n g D si n ig g it Co a l M nc o d Va eptu ell in l id a l g i 3D at in sing g Sc D ann ig it ing Ph a l M ot od o 3D gra ell in P phi g D rint ng ig i n it g Te al M st i od n Ite g ell in ra g t Re i n g fin Pr i n g ot o D typ ig i n it g Pr a l M ep od a D r i n el l i n oc g F g u i W me l e s rit nt in i Co ng g st i M ng an u Fi f a c ni tu sh r i D i ng ng et ai Ph l i n g ot o Re g ra fle ph i W ct i n ng rit g i Pr n g in t Pr i n g es e Ex nt in hi g b Re it in st i g ng

M 15 16 17

Reflect, Refine, Focus 18 19 20

Intensive Design Development

21 22 23 24

Finalise Design and Project Outcomes

25 26 27

Complete Production

28 29 30

Project Completion & Exhibition 27

Minds Behind Helmets:

Field & Research

Literature Review

As a method of understanding the field this project intends to act within, a range of existing research and literature has been explored. As opposed to attempting to locate research which supports any predetermined hypothesis, the activity was approached with a sense of objectiveness. The aim of immersion was instead favoured. The field of bicycle safety and helmets is a highly active area of research, and there is no shortage of information. In many ways, it is more challenging to synthesise meaning from the vast number of articles available. The following sections serve as a brief introduction to the range of research and influencing factors which surround bicycle helmets. Age Groups It is clear that specific age groups of cyclists respond differently to the idea of wearing helmets. A study conducted in the United States revealed that â&#x20AC;&#x2DC;the age groups with the highest rate of bicycle helmet use were 50 - 59 years, and older than 59 years. The age groups with the lowest rate of bicycle helmet use were 11 - 19 years and 30 - 39 yearsâ&#x20AC;&#x2122; (Altman et al 2001).

Minds Behind Helmets: Field & Research

‘ Teenagers are sensitive to peer opinions, and the attitudes of their peers is a factor in a teen’s choice to wear a bicycle helmet’ Children for example ‘have altered perceptions of how others view bicycle helmets and an unfounded fear of being teased, which leads to their lack of use at the age of 11–13 years.’ (Rezendes 2006) Teens are also of significant interest. They are at a transitionary age where they have the need to travel longer distances in which walking is not viable, but cycling is an accessible mode of transportation (Lajunen et al 2001). This is a key consideration since teenagers are sensitive to peer opinions, and the attitudes of their peers is a factor in a teens choice to wear a bicycle helmet (Lajunen et al 2001). In Australia, it is mandatory by law to wear a helmet while cycling. These attitudes of reluctance may be slightly subdued because of this law, however there is value in understanding why these age groups may be more reluctant to wear helmets. The project can then attempt to acknowledge these issues within new design directions.

Minds Behind Helmets: Field & Research

Peer Influence The significance of peer influence is thoroughly documented within not only the study of helmet wearing, but a range of safety behaviours which may not be perceived as necessary or valuable. Helmets closely relate to practices such as wearing seat belts in cars, or wearing lifejackets on water. In a small community in Northern Canada a resident stated how she liked to wear a lifejacket on water as it made her feel safe, but other residents with whom she associates think she is crazy for wearing one. (Giles et al 2010) In this case someone who is attempting to do the right thing is convinced otherwise simply by the view of peers. This can also be seen within motorcycle helmets. A study conducted in Iran revealed that many motorcyclists feared negative labels and subsequent critical reaction they receive from peers. A sixteen year old motorcyclist stated â&#x20AC;&#x2DC;when they first saw me wearing one, the teased me, telling me that I am scared of getting hurt.â&#x20AC;&#x2122; (Zamani-Alavijeh et al 2011) Again, since Australia has helmet legislation some of the boldness of wearing a helmet is reduced since everyone is supposed to wear one, but peer influence is still apparent. One of the most important considerations when thinking about how cyclists perceive helmets is that their attitudes may be multidimensional. (Kakefuda et al 2009) Single dimension enquiries may be able to reveal certain insights into why helmets are or are not perceived to be valuable, but the real challenges are more complicated. Through a deeper understanding of why helmets could be seen as a nuisance, this project aims to override some of the traction peer influence may have in deterring a person from wearing a helmet.

Minds Behind Helmets: Field & Research

Helmet Legislation Along with the debate over the efficacy of helmets, there is an obvious dispute over the effects of mandatory helmet legislation. Depending on the ways in which the issue is viewed, it is possible to reveal both benefits and downsides of forcing cyclists to wear bicycle helmets. There are many sources which indicate clear advantages since ‘bicyclists killed or admitted to hospital after sustaining a head injury decreased by 48% and 70% in the first and second years after’ the mandatory helmet law in Victoria was passed (Cameron et al 1994). Others point out that helmet legislation simply reduces bicycle riding by 20% – 40% and in turn may ‘have a large unintended negative health impact’ due to the reduction in physical activity ( Jong 2012). On a deeper level however the effects of helmet laws are quite simple in their intentions. There is ‘relatively high perceived social pressure to use helmets, and moderate levels of moral obligation and perceptions of control regarding helmet use.’ (O’Callaghan et al 2006). This project has commenced research in a city which has had this mandatory legislation in place for many years. It is quite rare to see a cyclist without a helmet and therefore this debate has been placed outside the scope of the project. There is a much stronger focus on the people who are perhaps reluctant, but still choosing to wear a helmet, and how this experience may be improved.

Minds Behind Helmets: Field & Research

The Space Between: Gaps In Research

It has become extremely clear that the evolution of bicycle helmet design and development is extremely linear and relies heavily on conventions or traditions. Through analysing the evolution of the bicycle helmet, It is surprising to see how advanced the technology and construction methods of EPS helmets have become. However in terms of true innovation or benefit to the cyclist, little has been explored or changed. In addition to helmet manufacturers, there is another active body within the field of helmets; the scientific research community. Countless studies have been conducted in order to reveal a range of insights such as the efficacy of bicycle helmets, and the social responses or behaviours towards wearing them. These two endeavours of design and manufacture, and social or behaviour research plot two separate points in the field, and they seem to lack any means of connection. This project argues that there is an opportunity to achieve a more useful and considered helmet design through the integration of these two fields. The role of this project will be to first become an expert within these separate fields, and then combine the knowledge of both to develop a new helmet which better responds to the needs of its users.

Minds Behind Helmets: Field & Research

â&#x20AC;&#x2DC; This challenge is often responded to through an advocation for helmet safety campaigns, educating people on why they should wear helmetsâ&#x20AC;&#x2122; There is great interest in not only determining whether or not helmets actually reduce the severity of head injury in accidents, but more importantly, the reasons and patterns behind the reluctance to wear them. Several States in Australia frequently appear within case studies due to the mandatory helmet legislation which exists across the country. A reoccurring theme within the research is the magnitude in which peer pressure affects helmet wearing practices. This challenge is often responded to through an advocation for helmet safety campaigns as a method of educating people on why they should wear helmets. This may be a valid suggestion, however it can be viewed as perhaps the only response such research bodies are capable of presenting. In most cases, a research project of this nature would not have the motivation, skills or resources to respond to the issue on many other levels. They instead respond with solutions that operate within the constructs of the existing helmet markets. The crux of the matter lies within the motivation for carrying out the research, which is not necessarily to design a better helmet. The aim is often much more concerned with identifying the social behaviours which exist as a result of current helmet designs.

Minds Behind Helmets: Field & Research

Bicycle helmet manufacturers have it in their interest to progress and innovate within their product lines. The advanced and lightweight helmets which many enjoy today are a direct result of this innovation. There must be however a consideration of viability in terms of how far this innovation can extend. It would be exceedingly costly to push the design of helmets to the point where it requires completely new approaches within manufacturing. This highlights a potential reason that most helmet manufacturers focus on iterative improvements of helmets such as the number of vents and the lightness or style of helmets. They have become limited to producing helmets from EPS, and therefore overlook the need of responding to or carrying out more extensive research on how its users could benefit from other designs. Users of course have influenced the products which the manufacturers have created, but this is still guided by the decisions that the designers are making. Because of the repetitive and proven production methods of helmets, it has become unnecessary to consider changing the way helmets are made. One is not inclined to fix something if it is not broken. This project instead views the reliance on existing conventions as an area of opportunity for new research.

Minds Behind Helmets: Field & Research

â&#x20AC;&#x2DC; This project instead views the reliance on existing conventions as an area of opportunity for new researchâ&#x20AC;&#x2122;

The identified lack of collaboration between the fields of social research and bicycle helmet manufacturing provides this project with a clear gap to operate within. By investing a great deal of effort to understand both of these fields, this project has the opportunity to respond to the issues surrounding bicycle helmet wearing on a much more comprehensive level. The cross pollination of these fields has been facilitated through the aim of becoming an expert in each of the areas. Immersion and documentation into the ways cyclists use and experience helmets has led to a series of realisations regarding existing helmet design. These discoveries are expanded upon in the following chapters.

Minds Behind Helmets: Field & Research

Identifying Oversights

Unlike a Glove In order to understand the complexities in helmet design, three primary styles of helmets were studied. This revealed a vast range of approaches to accommodating various head shapes and sizes. Most helmets on the market come in a set range of sizes, typically small, medium, large, and extra large. Since each size of helmet requires separate tooling to manufacture, extending a size range can be extremely costly. As a way of accommodating a broader range of head sizes, current helmets use highly compressible foam inserts to ensure an adequate fit. This is an economical and logical method of solving the issue. The problem with this method however is that it increases the relative size of the object for people at the smaller end of an individual size step. For example, a person whoâ&#x20AC;&#x2122;s head is only a fraction too big for a small size, must then wear a medium. In proportion to a person whoâ&#x20AC;&#x2122;s head just fits into the medium size, the helmet may look slightly out of proportion. The shape of the head is just as important since a person with a very round skull may need to wear a larger size if the helmets appropriate size is too tight on certain points of the head. Since the visual appearance of the helmet is often perceived to be a primary deterrent to wearing one, any ability to reduce the bulk of the object can be seen as beneficial.

Minds Behind Helmets: Field & Research

The relationship between a cyclistâ&#x20AC;&#x2122;s head and the helmet is difficult to comprehend. Image overlays begin to uncover the separations of style, function and fit.

â&#x20AC;&#x2DC; As a way of accommodating a broader range of head sizes, current helmets use highly compressible foam inserts to ensure an adequate fitâ&#x20AC;&#x2122;

â&#x20AC;&#x2DC; The goal of a less bulky, close fitting and comfortable helmet will be investigated through the combination of these new technologiesâ&#x20AC;&#x2122; This discovery acts as the seed of interest in investigating how the combination of 3D scanning and printing could be used to overcome the issue of overly bulky helmets. Since skull shapes are so diverse, 3D scanning would serve as a method of accommodating this individuality. 3D scanning has been utilised for the design of helmets before, but has been used in extremely high end helmets designed for sporting professionals. By combining this technology with additive manufacturing, the cost efficiency and viability of the process may have the chance to be greatly increased. The overall aim would be to make this process more available to the general public as opposed to highly funded sponsored athletes. The goal of a less bulky, close fitting, and comfortable helmet will be investigated through the combination of these new technologies. Although the immediate viability of these processes will remain challenging in terms of cost and access, the project sees the opportunities for development to be immense.

Minds Behind Helmets: Field & Research

Helmets and the Wind Tunnel With the context and users of the project surrounding urban cyclists, a peculiar question becomes extremely apparent. Why are the majority of helmets on the market designed with such strong focus on aerodynamics? The question very quickly flips from a response of ‘well because’, to, ‘hang on, why’? Through history, the helmet was primarily driven in response to the increased danger competitive cyclists are exposed to. Today’s competitive cyclists, such as those who race in the Tour De France, would see the seemingly minute science of reducing drag as imperative. This however is in stark contrast to the needs of urban cyclists. Cycling as a mode of efficient city transportation does not necessarily require such an intense focus on aerodynamics. Once acknowledged, it becomes almost humorous to review the overall forms of many helmet designs.

Minds Behind Helmets: Field & Research

â&#x20AC;&#x2DC; It becomes immediately clear how the excessive bulk of the object can contribute to a user feeling conscious about their looksâ&#x20AC;&#x2122;

The Melbourne City Bike Share helmet has been driven by the stylistic influence of aerodynamics. It values a feature which fails to serve cyclistsâ&#x20AC;&#x2122; on any valuable level aside from perhaps being of low cost.

To highlight this point, the City of Melbourne Bike Share helmet was examined. The complex form of helmets can make it difficult to understand shape and material thicknesses. To reveal how the head actually fits inside the form, photo overlays were used to place this relationship in view. This process is eye opening. It becomes immediately clear how the excessive bulk of the object can contribute to a user feeling conscious about their looks. In the case of the bike share helmet, the protruding rear faces fail to serve urban cyclists on any account. This is especially concerning considering how little of the head may actually be protected with this style of helmet. Urban cyclists often ride in congested areas sharing roads with cars. This project has made an assumption that increasing the coverage of the skull would be beneficial in terms of protecting a cyclist from a larger range of possible head impacts. The photo investigation was continued with two other major styles of helmets, a competitive road cycling helmet, and an urban style skateboard helmet which has been adapted for the cycling market. In terms of balancing a compact shape, along with increased head coverage, the urban helmet shows strong points. However it faces a challenge in terms of comfort due to its limited ventilation. This summarises the decision for this project to remove aerodynamics as the driving factor in design development. It instead places emphasis on a reduction of visual bulk, increased coverage of the head, as well as increased comfort through ventilation and fit.

Minds Behind Helmets: Field & Research

Impact of Impacts Although helmets may seem like relatively simple objects, they are comprised of a large number of materials and components. In todayâ&#x20AC;&#x2122;s world where we are becoming more aware of the impact of material objects, it is necessary to consider sustainability principals in their design. A product autopsy of the bike share helmet was used to reveal where helmets currently sit in terms of these considerations. Every individual component of the helmet was removed, unstitched, and unstuck to be laid out for review. This process changes the perception of helmets as being simple, to understanding how many items are placed in the most basic of helmets. A list of materials were documented including EPS (expanded polystyrene), PVC (Poly Vinyl Chloride), Nylon, Fibre Reinforced Adhesive tape, PVC adhesive tape and a range of other not easily identifiable materials. The individual decisions behind all of these material choices are justified on some level. On a whole however, this material combination does not consider what happens to the helmet when it is disposed of. There is an interesting shift of values when considering an object which is designed for safety. Sustainability considerations may receive less value if they were to undermine the productâ&#x20AC;&#x2122;s ability to carry out its intended safety function. This project places immense importance on including sustainability principles as an inherent part of the project.

Minds Behind Helmets: Field & Research

For what seems to be a very basic helmet, it is amazing to understand how many components are necessary, or perhaps unnecessary, to create a helmet.

Haphazardly

An example of one of the many ways a helmet can be secured to a bike. This method adapts a vent hole as a place to insert a lock through which is secure, however, since the vents were not designed for this excessive strain, the EPS shell may crack after repetitive locking and un-locking.

Throughout a photo study of the way helmets are used in the city, a common issue was revealed. Urban cyclists often leave their helmets locked with their bikes. It is an understandable practice since carrying a helmet throughout the day can be cumbersome. The problem seen in almost all of these cases however, was that there is no logical or simple method of locking the helmet with the bike. It often results in the helmet being splayed out haphazardly from the bike which in itself causes yet another issue. Since the helmets are left dangling from locks, other cyclists may cause damage to the already locked helmet as they attempt to lock their bike next to it. Since bicycle helmets are not only a regulated safety object, but also manufactured from the somewhat fragile material of EPS foam, it is common to see helmets which have cracked. Bicycle helmets are designed to catastrophically fail in the event of an impact. This prevents a cyclist from using an unsafe helmet after a crash. The problem is that this failure mechanism may be the result of everyday use within the city and the stress it sustains through locking and unlocking. This point relates to the concerns surrounding sustainability. The project sees this as an area which needs to be specifically addressed for urban cyclists.

Minds Behind Helmets: Field & Research

Structuring New Approaches:

Research & Development

Structured Impacts

An example of a patterned infill within the internal space of a 3D printed model. Infill patterns reduce the material usage and therefore weight of a printed object.

Additive manufacturing or 3D printing traditionally sits within the space of prototyping. As the technology has been introduced to the consumer world through low cost and easy to use platforms, it is an industry which is very much at the forefront of its potential. People from around the world are continually coming up with new and inventive ways of using the technology. While this is exciting, and has truly facilitated ways of working which have never been possible before, additive manufacture is not immune to limitations. This project embraces the excitement surrounding the process with an acknowledgment of its requirements and current limitations. In terms of manufacturing a helmet, several advantages have been highlighted. This is a proposition which is entirely foreign. It has therefore required testing to prove whether or not the material properties of additively manufactured structures are even capable of meeting the various requirements necessary to produce a viable helmet.

Structuring New Approaches: Research & Development

â&#x20AC;&#x2DC; The weight of the helmet is extremely crucial since an excessive amount of weight may actually be detrimental to cyclists in the event of a crashâ&#x20AC;&#x2122; The immediate concerns with using this process is whether or not 3D printed material could compete with existing foam helmets in terms of weight and strength. The weight of the helmet is extremely crucial since an excessive amount of weight may actually be detrimental to cyclists in the event of a crash. Added weight on the head can cause additional strain or injury to the neck and spine, therefore any 3D printed helmet would have to compete with the weight of existing helmets which tend to be around a maximum of 450 grams. 3D printing primarily uses solid plastic material as opposed to the aerated plastic known as EPS. 3D printing is however capable of printing hollow and complex structures as a way of decreasing the material density in objects. This becomes the balancing act within the hypothesis. Decrease the density too much and the helmet may not offer enough impact absorption. Increase the density and the helmet may exceed the maximum weight. Since all of these aspects were completely unknown, a standard method of drop testing material was established.

Structuring New Approaches: Research & Development

The cubes printed on a desktop 3D printer fail primarily due to the layers separating under stress. This displays that 3D printing is not a universal process and must be carefully considered based on functional requirements.

Using a digital model of a 50mm cube, 3 samples of varied infill density were printed on a desktop printer. Although there are a range of patterned structures which can be used to fill the void of a modelâ&#x20AC;&#x2122;s internal space, a standard cross pattern was selected. The test was not rigorously planned enough to be considered scientific, however there was an attempt to remove as many factors as possible which would cloud the results. The simplest shape was combined with the simplest infill pattern in hopes of getting clearer results from the tests. The next phase involved creating a test rig which could consistently apply a certain amount of force or impact to the samples. A bearing guided rail system was assembled with a weighted cross bar. The cross bar had a foot installed to crush stationary material samples below. Video was used to document as 5%, 12.5% and 25% density printed cubes were crushed. This was then followed by an equally sized block of EPS.

Structuring New Approaches: Research & Development

The results of the tests were promising and provided enough support that 3D printed structures have the potential to match the impact absorption of EPS. Through analysing the rebound height of the cross bar off each sample, albeit uneducated, a conclusion was formed. The 12.5% density sample had the highest impact absorption to weight ratio in comparison to EPS, and was therefore selected as a rough estimate of how dense the infill of a 3D printed helmet might need to be. It must be made clear that these experiments do not claim any hard facts, and act only to validate whether the balancing act of weight and strength may have a chance to compete with current foam helmets.

5% Infill

12.5% Infill

25% Infill

EPS

12 grams

18 grams

30 grams

4 grams

There are several materials and processes within additive manufacturing. The most common types of printing include SLA (stereolithography), FDM (fused deposition modelling) and SLS (selective laser sintering). Each of these processes possess unique characteristics and limitations. SLA has become a standard for producing high quality models with incredible detail. This is due to the fact that it uses a laser to cure photosensitive liquid resins and can achieve extremely fine layer heights. This process does however lend itself more toward prototyping applications as the resins can remain sensitive to UV light and are subject to degradation over time. FDM printers are what is seen at the low cost consumer end of 3D printing. These printers are incredibly simple in design and use a heated nozzle to extrude plastic filament which is traditionally made from either ABS (acetal butyl styrene) or PLA (polylactic acid). The downfall of these printers, especially in terms of the helmet, is the problem of delamination. Delamination refers to the individual layers of plastic pulling apart from one another when stress is applied to the material. These printers also face limitations in terms of geometry as gravity has a tendency to let the molten plastic droop as it cools. Finally SLS printing uses a laser to sinter or fuse powdered material together. This has been selected as the most viable process to manufacture a helmet. It is capable of producing a highly durable and consistent material, it is much more flexible in its ability to print complex structures, and prints in materials which are resilient and can withstand exposure to UV.

Structuring New Approaches: Research & Development

A very early experiment of how structures could be made lightweight, yet remain strong. These concepts explored the complex geometry 3D printers are capable of producing.

Mapping a Skull

As a method of overcoming the poor fit and generalised shape of helmets, 3D scanning has been researched. The use of this technology aims to improve the level of personalised fit within a cyclistâ&#x20AC;&#x2122;s helmet. Throughout recent years, a range of consumer level scanners have come on to the market. This demonstrates raised demand and awareness of the technology. The process of scanning a physical object is often made to sound extremely straight forward, but it has been discovered that this is not always the case. When considering a human skull, the shape is incredibly complex and unique. Since scanning most commonly involves the rotation and orbit of a hand held scanning device around the object, there can be immense possibilities to end up with a dimensionally inaccurate scan. The sophistication and accuracy of scanning equipment greatly improves at the higher end of the price scale. These scanners often have their own proprietary software for collecting and translating the scanned data. In the case of this project, several scanners were investigated. After a review of different options, an Artec handheld scanner was selected. This scanner possessed a high ability to record data which was dimensionally accurate, and also proved to be relatively easy to work with.

Structuring New Approaches: Research & Development

The Artec scanner used to record all of the 3D models of heads throughout the project.

A small FDM scale model of the projectâ&#x20AC;&#x2122;s first 3D scan. The process of digitising, and then transforming back into the physical was quite peculiar.

Once the scanner had been selected, a test scan of a head was carried out. Little exposure to scanning a human head meant the process was carried out in an entirely experimental format. It simply involved sitting a person in a rotating chair, holding the scanner at stationary angles and distances, and slowly rotating the person. The scanner has the tendency to loose track of its previously scanned data and can cause the entire scan to need restarting. It was found that slow and consistent rotation of the head allowed the scanner to finally capture an accurate point cloud of data. Once the scanning is complete, a series of post production techniques are needed to register or align the various points of the scan together. Prior to completing the registration, the scan can look as though there are several fragmented scans randomly placed near one another. Almost magically, after the scan is registered, a very recognisable and detailed scan is displayed. Visually the scan can look complete, but there are still a number of post production processes needed to make use of the scan. Repairing and cleaning the scan removes all the unwanted data and errors. The scan is finally converted from a polygon mesh into NURBS surfaces.

Structuring New Approaches: Research & Development

â&#x20AC;&#x2DC; Once the scan was translated into a 3D modelling program, estimations had to be made in terms of where the skull actually sat below the hairâ&#x20AC;&#x2122; This first scan proved that the process of scanning is a relatively easy method of recording an incredibly complex shape. However an oversight was made within this first scan. With all of the effort invested in carrying out the first scan, there was a failure to remember how hair can mask the actual shape of the skull. The head which was scanned was of a male with relatively short hair, but this meant that once the scanned data was translated into a 3D modelling program, estimations had to be made in terms of where the skull actually sat below the hair. This oversight then contradicted the aim behind 3D scanning which was to make sure the helmet could be modelled exactly around the individuals head shape. A second scan was carried out with a tight elastic material stretched over the head. This compacted the hair effectively enough to see the true shape of the head. This method would also be effective for people with long or dense amounts of hair. Since the hair is compacted in a realistic manner, it means that not only is skull shape accounted for, but also variable hair styles.

Structuring New Approaches: Research & Development

A smooth dark coloured material assisted in recording a seamless scan since hair often throws the scanner off track. This method of compacting the hair was very successful.

â&#x20AC;&#x2DC; A second scan was carried out with a tight elastic material stretched over the head. This compacted the hair effectively enough to see the true shape of the headâ&#x20AC;&#x2122;

A digital rendering of the successful scan. Additional smoothing was applied to the digital model during post production. This assisted in removing any unnecessary surface imperfections.

Once the second scan had been cleaned and converted, the surfaces were imported into a 3D modelling program. This then presented a new challenge which considered how to best utilise the data. Constructing a uniform wire mesh around the scanned data proved to be the most viable. Once this wire mesh was established, surfaces were generated to form what would be the inner surface of the helmet. Since digital data can be difficult to validate until made physical, simple 1mm thick versions of this surface were printed out on a desktop FDM printer to be tested. Due to the limited size of the printers build platform, the model had to be divided into sections which were then bonded together to produce the physical shell. This presented new challenges since the thin printed walls had a tendency to warp slightly during printing. Several iterations of these print samples were produced. After ending up with what was tested to be an ideal fit for the head shape, the project was able to move on to generating what would be the actual helmet itself. In reflecting upon the process of scanning, there were many challenges which required a large investment of time. This projectâ&#x20AC;&#x2122;s process of scanning would immediately cause the production prices of such a personalised helmet to surge past any viable means. With this stated, it does not however mean that it could not be improved or simplified in the near future. Once a standardised and proven method of scanning is established, this process of scanning has the opportunity to be made available in a number of ways, and will be discussed in the coming chapters regarding the future scenarios of the project.

Structuring New Approaches: Research & Development

Wrapping a Skull

With an understanding of the inner shape of the helmetâ&#x20AC;&#x2122;s surface, the actual helmet itself could be modelled. Through research conducted in the early stages of the project, a direction regarding shape and style had been defined. A focus on the increased coverage of the head lent itself most strongly toward the skate or urban influenced helmets. With the majority of road style helmets, the rear and side of the head remain relatively exposed. This influenced the approach to the initial design of the helmet. Skate or urban styled helmets also seemed to be prominent within the defined user group of city cyclists. This may be to do with its associations in the culture and lifestyle of extreme sports, or to do with its more understated form compared to the more aggressively styled road helmets. Instead of attempting to simply recreate this style of helmet, the scanned data of the userâ&#x20AC;&#x2122;s head was left to drive the form of the helmet. The location of ears on the head drove the side profile of the helmet, and the shape of the brow and the rear of the head determined the front and rear profiles. Since the project did not have access to any viable method of conducting structural tests within a digital model, the thickness of the walls around the head were roughly based off existing helmet designs. The reduction of visual bulk or size became an extremely important aspect of the design. The inner surface drove all dimensions of the external shape and therefore attempts to reduce the actual size of the helmet.

Structuring New Approaches: Research & Development

â&#x20AC;&#x2DC; A focus on the increased coverage of the head lent itself most strongly toward the skate or urban influenced helmetsâ&#x20AC;&#x2122; At this stage of the process physical validation of the form was required. Since the previous prototypes of the printed inner surfaces were slightly inaccurate as well as time consuming, a simpler method of prototyping was needed. Laser cut interlocking card slices proved to be incredibly efficient, and were also accurate enough to ensure that the digital model was dimensionally correct. The rough block form that had been modelled was sliced into 2D profiles and nested into a vector based file. After the simple process of laser cutting rigid card had been carried out, the models were quickly assembled. This process could be completed in under a couple of hours. Comparing this to the 8-10 hours required to print extremely thin profiled FDM models, the advantage was clear. The shape of the helmet, even in card, felt extremely compact compared to other helmets. From this point onward, the project moved toward higher and higher levels of refinement in terms of the helmetâ&#x20AC;&#x2122;s shape. However several aspects of this project needed to develop concurrently with the form in order for the project to have any chance of being successful.

Structuring New Approaches: Research & Development

The density of infill had been roughly explored within previous experiments, however the actual structure itself was still unknown. The nature of the infill structure was envisioned as a structure which could be dynamically or parametrically adjusted. Similar to the way car manufacturers design crumple zones within the bumpers of cars, a complex structure could be adapted for the helmet through further and more extensive testing. The scope of this project set out to represent what this structure may look like, and make an attempt to facilitate the ability to vary the density of infill simply. When considering the different angles of impact the cyclists head may experience, a radial infill pattern was explored. A simple cone structure was modelled and then repeated around a central axis. By creating a large block of this structure, any helmet shape and size could be digitally subtracted from the body and used to infill the internal cavity of the helmet. This concept requires great consideration to not only ensure the helmet will be capable of absorbing impact, but also viable in terms of creation through SLS printing. Since the helmet and internal structure were conceived to be printed all in one, the internal structure became very important in informing the helmetâ&#x20AC;&#x2122;s over all design.

Structuring New Approaches: Research & Development

A concept of a radial infill pattern. The radial nature of the structure aimed to ensure no matter which way a cyclist hit their head, the structure would be most capable of withstanding the impact.

Within the first phase of the project, a small yet important detail was discovered. Skate style helmets suffer a simple downfall in terms of the straps. When the skate helmet is compared to a road style helmet, there is a great separation in terms of comfort. This is due to the fastening method and location of the straps. On the skate helmet, straps are typically riveted to the outer hard shell. This location offsets the straps away from the head and causes the straps to converge toward the chin area. Almost all of the contact along the face happens at or below the chin. The road helmet however does not have the ability to rivet straps on its side since it lacks a rigid outer shell. It instead mounts the straps inside the helmet near the side or top of the head. This provides a much higher level of comfort since the straps then closely hug the sides of the face as it wraps under the chin. Once acknowledged the comfort difference is black and white. This project worked to accommodate this feature and carefully considered how the straps would best be mounted from the inside the helmet. This design detail helped form the overall shape of the helmet and is discussed further in following chapters.

Structuring New Approaches: Research & Development

â&#x20AC;&#x2DC; Skate helmet straps are typically riveted to the outer hard shell. This location offsets the straps away from the head resulting in the straps converging toward the chin and causing discomfortâ&#x20AC;&#x2122;

As the project moved into its refined stages of form development, a final validation through prototype was constructed. Although the interlocked card models were effective at validating fit, they failed to accurately represent form and visual considerations since they lacked a solid outer surface. Having access to a KUKA robot enabled a solid model to be milled out of EPS. This ended up being an odd combination of processes and materials as the project was producing prototypes from the material which it was attempting to replace. The foam model faced complications as the material had to be manually flipped during the cutting process. This resulted in the inner and outer surfaces being misaligned and therefore skewed the overall shape of the helmet. Regardless of these errors, the model did still serve its purpose of representing the overall form, and confirming the shape and feel of the helmet. The helmet fit dramatically closer to the head and was considerably smaller than existing helmets.

Structuring New Approaches: Research & Development

Simplifying Ingredients

A significant portion of the projectâ&#x20AC;&#x2122;s development has stemmed from an acknowledgment of sustainability principles. The number of components, the materials, and the construction methods of existing helmetâ&#x20AC;&#x2122;s raise many concerns in terms of being designed for durability, disassembly and end of life. Since 3D printing is capable of producing a range of complex geometry which traditional moulding processes are incapable of, it allows the project to consider a single material and unified shell. Rather than responding to the functional requirements of the helmet on an individual basis, the helmet has been developed as a whole. This presents new challenges within helmet design and has resulted in several unique solutions being developed through the project. The first question was how to efficiently fasten the straps within the helmet. Existing helmets use two main methods. The first is found in skate style helmets. The rigid outer shell is strong enough to rivet the nylon straps in place. This is an extremely durable fastening method but has been discover to be not only uncomfortable, but also difficult to repair or disassemble. In contrast, road helmets use slots within the EPS itself. Since EPS is not durable enough to fasten directly to, plastic clips support the strap from the outside of the helmet.

Structuring New Approaches: Research & Development

â&#x20AC;&#x2DC; 3D printing is capable of producing a range of complex geometry. It allows the project to consider a single material and unified shellâ&#x20AC;&#x2122; Since these clips are visually distracting, there is often an attempt to mask them through surface details or additional materials. 3D printing has allowed the project to consider integrated methods of fastening. An initial concept of a self locking clip was explored through several prototypes. Through this development, a secure clip was created which allowed a looped strap to be inserted without any additional components. Once the strap is inserted, it is extremely secure. In addition to the simplicity of installation, the straps can also be removed if the loop is manipulated out of the clip in a specific manner. Once the clip was tested, it was simply a matter of locating where these needed to be embedded within the helmetâ&#x20AC;&#x2122;s surface. Referencing photographs of the side profile of the head, the location of the chin and ear drove the optimal mounting points. By placing the clips higher within the helmet it facilitated the desired close fit of the straps along the head. The front and rear clips were located based on the angle necessary for each strap.

Structuring New Approaches: Research & Development

Another point of interest is the padding on the inside of helmets. Padding is a crucial feature. It primarily ensures a proper fit since the sizes of helmets are highly generalised, but also adds a level of comfort for the user. In the case of this research, the padding is less likely to be required for issues of fit since the inner surface is tailored to the userâ&#x20AC;&#x2122;s head. In considering the final material of nylon plastic however, some level of padding is still required for aspects such as sweat and skin contact. Most of the foam padding used inside helmets today relies on adhesive velcro tabs holding it in place. This can be completely frustrating as the padding often moves over time and is prone to falling off. Considering how often a helmet may be worn, taken off, locked and left during short city rides, this becomes a large annoyance with helmets. On top of the functional concerns, placing adhesive velcro onto the EPS helmet becomes yet another material to complicate end of life processes. The project again leveraged the process of additive manufacturing. Rather than using adhesive or velcro, a concept of a framed recess was developed to hold material. The first question quickly became about which material should be used. The material needed to accommodate the user in terms of comfort, sweat absorption and durability. A second consideration involved the specific structural characteristics necessary to remain secure within the helmet. 92

Structuring New Approaches: Research & Development

A first experiment into adhesive and velcro free padding. The part was printed as two halves to simplify the printing process.

â&#x20AC;&#x2DC; Most of the foam padding used inside helmets today relies on adhesive velcro tabs holding it in place. This can be completely frustratingâ&#x20AC;&#x2122;

The first sample was successful, however, it was too rigid since the walls of the material were quite thick. The curvature of the tabs were also too sharp, and the padding itself needed to be much wider.

Neoprene has been selected as an appropriate candidate for these reasons. Since the concept relied on an internal recess within the inside of the helmet, a method of raising the material past the surface and toward the head was needed. This was solved by creating flexible and protruding tabs within the recess. With these components combined into a single structure, 3D printed prototypes were tested. Several iterations were needed in order to produce a successful version. Eventually these efforts resulted in a completely simple and adhesive or velcro free method of fastening padding within the helmet. Studies were conducted using the foam prototype in order to determine the best locations for the padding around the head. Complex modelling was required to insert these padding recesses along the curvature of the appropriate locations inside the helmet.

Structuring New Approaches: Research & Development

Although the development of the helmet has been influenced through the form of urban or skate style helmets, a downside of comfort has been identified. Skate style helmets are the least vented variation of helmet. In the context of Melbourne and Australia, summers can be extremely warm. This therefore influenced the decision to ensure the helmet was highly vented. This aim turned out to be more challenging than expected. Working with the digital model, a range of approaches to venting and patterns were explored. None of these options suited the visual style of the helmet and resulted in the appearance of random holes being cut out of a form. It was at this point in the project that a realisation was made. The reason these vents seemed so unfitting was because this approach to venting was intrinsically linked to the EPS traditional helmets are made from. This research however proposes an entirely new method of production and therefor makes a reliance on tradition irrelevant and somewhat wasteful.

Structuring New Approaches: Research & Development

â&#x20AC;&#x2DC; The reason these vents seemed so unfitting was because this approach to venting was intrinsically linked to the EPS traditional helmets are made from.â&#x20AC;&#x2122;

‘ It was realised that these escape holes could allow air to flow through the helmet, and act as ventilation’

By assembling boxes of the perforated samples, the effectiveness of airflow could be tested by blowing air into the faces. A range of hole sizes were considered for not only airflow, but also aspects such as rain, insects and dust.

The problem regarding the vents was not only a visual predicament, but also a functional one. As highlighted, SLS printing forms objects by fusing layers of powdered material together with a laser. This process leaves unfused powder inside any internal void within the part. If traditional vents were cut into this helmet’s form, it would leave no method of removing the unused material from the inside cavity of the printed helmet. This then led to the consideration of escape holes being strategically placed within the helmet. Once this concept was explored, it was realised that these escape holes could allow air to flow through the helmet, and act as ventilation. Since the complexity of geometry becomes less of an issue with additive manufacturing, perforation of the helmet’s surfaces was investigated. By using a small but dense hole pattern, it ensured that no location within the helmet would lock unused powder inside. The exact pattern was developed through tests on laser cut card. This provided an effective way of visualising and feeling how the patterns would function. A final elliptical hole pattern was refined for the helmet.

Structuring New Approaches: Research & Development

The Unattended

Throughout the focus on researching urban cyclists, it has become apparent that current helmets completely overlook an important behaviour: city cyclists lock their helmets to their bikes. This is an obvious response as carrying a helmet throughout the day can be tedious and cumbersome. The problem is however that this process of locking a helmet is actually quite difficult. There is no obvious, simple or secure method of locking a helmet to the bike. Helmets also risk damage from this practice alone since they have not been designed for this purpose. This project attempts to address this problem. Through research it was found that the easiest helmets to lock were those which had vent holes large enough to place a lock through. This is problematic since the vents are weak points within the EPS. Any unnecessary strain on the helmet can cause them the crack and therefore become unsafe. Due to the added durability of 3D printed material, a specific locking slot was investigated. The overall function of the slot becomes more apparent as it is the only hole within the helmetâ&#x20AC;&#x2122;s structure. The size, location and shape of the slot have all been influenced by locking practices, optimal helmet positioning next to a bike, and the size of common locks. The rear face of the helmet has been determined to be the most logical area for the hole to exist.

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Structuring New Approaches: Research & Development

Experiments in understanding how best to orient the helmet while locking.

The Shape of Prints to Come

Since most of the design details of the helmet had been developed, it was now time to translate these individual ideas into a single material body. All prototyping up to this point had been produced in materials which differ slightly from the specified material. None of these prototyping methods such as foam prototypes or FDM printing are capable of producing the complex geometry of the helmet. Since there was still some uncertainty in whether all of the helmetâ&#x20AC;&#x2122;s details would function appropriately, a cutaway sample of the helmet was printed first. Working with the AMP (Advanced Manufacturing Precinct) at RMIT University, an SLA resin print was produced. The largest concern prior to printing was whether or not the wall thickness of just 0.7mm would form a strong enough structure. All of the internal supports, as well as inner and outer helmet surfaces, were formed from this thin skin. On its own, the material walls are incredibly flimsy and offer no real strength. However once it was printed, the strength of the entire assembly was incredible. This was a pleasant surprise to have all of the research and development so far translate accurately into the first test.

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Structuring New Approaches: Research & Development

The specific cutaway pattern of the first printed prototype was selected in order to include all of the helmetâ&#x20AC;&#x2122;s important features within one small sample.

105

‘ Smoke was used to view how air passed through the object. Since the perforations are so fine the smoke is diffused slowly through the body of the helmet’ Having the test section of the helmet allowed specific traits of the helmet to be validated. One of these traits was the venting. Without being able to strap a full helmet onto a user’s head, other methods of visualising airflow through the perforations was used. By simply lighting a candle and then blowing it out, smoke was used to view how air passed through the object. Since the perforations are so fine the smoke is diffused slowly through the body of the helmet. This differs from the direct airflow which would be felt through a traditionally vented EPS helmet. Testing with the full helmet will verify whether this is an appropriate method of cooling the user’s head, or whether it is detrimental and results in the cyclist’s head becoming too warm. On any level, this simple test verified that the helmet’s shell is indeed permeable, and in theory should assist in cooling a cyclist’s head as they move through air while riding.

Structuring New Approaches: Research & Development

107

The final prototypes material was intended to be produced from nylon using SLS. This material was selected for its resilience, durability and ability to withstand the elements an urban cyclist experiences. Due to limitations in the project schedule, this process became quickly unviable as production and shipping times extended beyond the projectâ&#x20AC;&#x2122;s completion date. Since the SLA cutaway sample was so successful in terms of demonstrating the helmetâ&#x20AC;&#x2122;s potential, a decision was made to produce the entire helmet with SLA. The positive side of this decision was that SLA and SLS have very similar manufacturing requirements in terms of escape holes to extract unused printing material. SLA draws the printed object into a liquid resin tank during printing, and in this way, needs holes to drain the excess material from within the helmet walls. Although this prototype will lack some of the material qualities which nylon would exhibit, this project is about representing a body of research as opposed to producing a market ready product. In this way the inherent material qualities become less of a concern as it will not be intended for direct use. The benefit of printing in SLA is that the helmet is produced locally and with the collaboration of RMIT University.

108

Structuring New Approaches: Research & Development

‘ Since the helmet contains a large number of holes, a solid model of the helmet was used to generate supports. This prevented supports from being placed inside the helmet’s voids’ The process of producing the final print was straight forward considering the cutaway sample had already validated the process. Printing in SLA did however present additional complexities to overcome. SLA printing requires supports to hold the object in place on the print bed and to assist in printing overhangs. Since the helmet contains such a large number of holes at varying angles, the support structures often end up being generated inside of the helmet’s body. This makes the process of removing these structures after it is printed almost impossible and extremely time consuming. It is to the point where this printing trait contradicts the design and need for the perforations. To overcome this a solid variation of the helmet was used to generate the support structures. In this way, all of the supports terminated at the outer surfaces of the helmet, and supports were prevented from being placed inside the helmet’s voids. Once the print had been completed it required minimal finishing since the print resolution of SLA is excellent. Light finishing with a fine grit paper was all that was required.

Structuring New Approaches: Research & Development

111

Since the helmet was to be exhibited, there was a concern that the clear material of the final helmet would cloud the intentions of the object. This clear resin material speaks very naturally as being a prototype, which is fine, except that it may confuse the viewer as to whether or not this is the final material and manufacturing process, or if it represents a completely different method of manufacture. To overcome this, the helmet was treated through a dyeing process to add a finished colour. By simply changing the colour of the material, the line between being a prototype and a manufactured artefact was blurred. Having previous experience dyeing SLA prints made the task of dyeing the helmet very straight forward. It requires a specially formulated dye which can be absorbed into the surface of the resin. After 30 minutes in a dye bath, the entire inner and outer surfaces of the helmet are treated with a durable finish. This process would become unnecessary if the helmet was printed in nylon as the nylon can be pre-coloured, but was a simple process which adds additional qualities to the final artefact. Once the helmetâ&#x20AC;&#x2122;s shell had been completed, it was simply a matter of installing the straps and padding into the helmet.

112

Structuring New Approaches: Research & Development

Lowering the helmet into the dye bath. The helmet remained submerged for 1 hour with regular agitation to ensure a consistent finish across the entire helmet.

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Sum of All Parts:

Project Outcomes 117

Cross Section Exploded View

119

Kobi: Outcomes & Features

3D scanned customised fit

3D printed unified shell

Accommodates a range of head shapes and hair styles

Simple and durable design

Increased protection around the temples, side and rear of the head

Encourages users to leave the helmet locked to the bike

Reduction of overall size and visual bulk

Designed specifically for the advantages and requirements of 3D printing

City specific functionality preferred over aerodynamics

Singular feature stands out to help inform the user of its purpose

Maximised head coverage

Dedicated locking point

Variable infill structures

Perforated surfaces

Integrated strap mounts

Integrated padding mounts

Ability to engineer specific support structures based on requirements

Acts as escape holes to remove excess 3D printed material after production

Minimal components

No adhesives, rivets or velcro

Density, strength, weight made variable through additive manufacturing

Highly ventilated for cooling during hot summers

Designed for disassembly

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â&#x20AC;&#x2DC; The helmet is surprisingly light and competes with what are categorised as relatively lightweight EPS helmets. There is an opportunity to reduce the weight even further as the internal structures have not been optimisedâ&#x20AC;&#x2122;

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â&#x20AC;&#x2DC; The sensation of airflow is unique. You can feel a lot of air passing through the helmet but it is gentle and satisfyingâ&#x20AC;&#x2122;

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User Feedback & Testing

As the project had carried out the majority of development around a single skull shape, the ability to compare fit across several heads became of less importance. However, there was a keen interest to gather feedback from the cycling community regarding the projects propositions. A local bike store was approached and provided feedback on the project. It became immediately clear that the project requires the back story and justification before the concept can be truly understood. It can be easy for designers immersed within work to overlook the complexity of ideas. Once the foundations of the project had been discussed, the feedback was very positive. While speaking to the owner of the shop, the project received high amounts of praise stating that the helmet was really cool, surprisingly light, and found the idea of custom fit helmetâ&#x20AC;&#x2122;s very exciting. They also commented on how simple all of the helmets padding and straps were. The main concerns or questions regarded both the safety of the helmet compared to the existing Australian and New Zealand standards, along with the price viability of such an item. These concerns have been explored throughout the project and it was satisfying to see the projects research has acknowledged these areas appropriately.

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Sum of All Parts: Project Outcomes

Applying force to the helmet revealed how strong the printed shell really was. The density of the infill structure would most likely need to be reduced in order to effectively absorb impacts. The prototype produced is overly rigid.

â&#x20AC;&#x2DC; While speaking to the owner of a bike shop, the project received high praise stating that the helmet was really cool, surprisingly light, and the idea of custom fit helmets was found to be very excitingâ&#x20AC;&#x2122;

Research Futures

Throughout the duration of the project, there have been numerous suggestions and ideas regarding the future potential of this research. This has been viewed as encouraging and validates the interest and possibilities of the work. By proposing a new method of manufacturing a bicycle helmet, it allows the project to explore many new aspects such as fit and component integration. Yet as it stands today, this process is not viable or accessible to everyday cyclists. This is primarily due to the cost of not only producing a 3D printed helmet, but also the time and steps required to design it with such personalised specifications. As a way of understanding when or how this process may reach future levels of viability and application, a series of scenarios and details will be reviewed through this chapter.

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‘ The goal would be to infill the helmet with a topologically oriented support system which would be driven by the curvature of the cyclist’s skull’

The most immediate opportunity for further research lies within the engineering of the helmet’s internal structures. The structure presented in the final helmet was largely based on hypothesis and a very basic understanding of how to make structures lightweight yet strong. This took into account the directional forces which could result from an impact at any point on the helmet. However, since the engineering of structures falls beyond the abilities and scope within the project, external advice on the matter was required. A discussion with Martin Leary (Senior Lecturer at RMIT’s School of Aerospace and Engineering) shed a lot of light on the potential in additively manufactured structures. He discussed the ability to design specific structure systems which could absorb impacts in a highly calculated manner. There were also discussions surrounding how this process of infilling the helmet’s interior could be automated through advanced software as opposed to being manually designed for each helmet. The ultimate goal would be to infill the helmet with a topologically oriented support system which would be driven by the curvature of the cyclist’s skull. Upon the completion of the design of these structures, rigorous material testing would need to be conducted in order to meet the Australian and New Zealand helmet standards.

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An example of the complex structures 3D printing is capable of manufacturing. The specific structure needed for a helmet is unknown but would be infinitely controllable within this production process.

â&#x20AC;&#x2DC; Bicycle retailers make logical candidates for offering scanning services as they already carry out tailored sizing to ensure adequate fit for the individual and bicycle frameâ&#x20AC;&#x2122; Although scanning was carried out in a relatively easy manner within the research, it is still complex enough and presents challenges in both recording and making use of the data. If the process were to become available to the general public, there would need to be facilities in place where people could go to acquire a scan of their head, or a way of users generating scans themselves. Since the hardware and scanning devices are quite expensive, it would make the most sense to envision cyclists visiting a bicycle retail store or dedicated business where the scans could be carried out in a specialised and regimented fashion, similar to the way passport photos are recorded to produce consistent results to required specifications. Although 3D scanners have entered the consumer market, the varied levels of capability, accuracy and factors which influence the quality of the scanned data are extensive. This makes the prospects of self scanning less viable. Bicycle retailers make logical candidates for offering scanning services on behalf of a manufacturer as they already carry out tailored sizing to ensure adequate fit for the individual and bicycle frame. Since a small team would become highly experienced in the process of scanning, challenges such as various hair styles and requirements across user types could be worked into scanning techniques in the most effective manner.

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The steps required to generate a custom fit helmet based off a scan were immense. This is another aspect of the project which leads to an extremely costly product. Since this project uncovered a new helmet design process without any previous knowledge of 3D scanning a human head, this can be viewed as the worst case scenario. It is one which has ample opportunity to be streamlined in process. The immediate challenge is how the scanned data can be efficiently translated into the generation of the helmetâ&#x20AC;&#x2122;s shell. The research utilised a completely manual 3D modelling process where each curve, dimension and detail were meticulously generated. This required well over 30 hours of time since the scanned data acted merely as a reference to model around. Only in reflection of this process can certain details be viewed as a potential blueprint for a helmetâ&#x20AC;&#x2122;s features. If these features were treated as a blueprint, methods of automating the generation of the model based on scanned data could become feasible. As opposed to the scan only being used as a reference, the scanned data could fundamentally drive this automated process. If a standard set of variables could be manipulated by the personalised data, the process could be dramatically decreased in terms of time investment. This method of modelling is completely parametric and the approach is already seen in software such as the Grasshopper plugin for Rhino. Ideally a varied range of helmets could be designed as recipes or algorithms into which a users scan could be entered. The majority of effort would be consolidated into the generation of robust algorithms. These could then be utilised to create any number of personalised helmets. This is an extremely complex concept but would be immensely interesting to see developed.

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Wireframe drawings of the scanned data. NURBS surfaces were automatically generated through a series of post production processes.

‘ With the momentum currently seen in the 3D printing industry, costs can be expected to decrease dramatically’

The cost for producing the physical prototypes for the project were exorbitant. Although though these costs have decreased dramatically with ongoing demand and development of 3D printing, the cost of producing high quality printed objects is still excessive, especially considering the scale of this object. If the helmet produced within this project were to be sold as a marketable product, it would far exceed reasonable cost since printing alone had been quoted in excess of $1000. However, with the momentum currently seen in the 3D printing industry, costs can be expected to decrease dramatically. What’s most interesting is to consider the cost breakdown of a printed object. The majority of the costs are quoted as machine time or space along with labour. Material is typically the least expensive component of the cost. In some cases material may only equate to a few dollars. It remains questionable how close the 3D printing of a bicycle helmet could come to the cost of mass manufactured EPS helmets, but the number of advantages in such a customised or bespoke object can be viewed as a motivation for spending slightly more on a helmet.

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Support material must be removed from the print before it is cured under UV. The model is in a “green” state and remains somewhat fragile until curing is complete.

‘ Flexibility and resilience in a helmet raises the question of whether a helmet could be designed for multiple impacts as opposed to just one’ With the momentum present within 3D printing, new processes and materials are being discovered rapidly. Opportunities to print in varying degrees of flexibility is an interesting proposition for future research. Most of the printed materials available today are of a relatively rigid nature. When thinking about the impact of a cyclist’s head during an accident, these types of materials would have the tendency to simply break or fracture. This matches the behaviour of EPS helmets which are designed to fail as a result of an impact. Flexibility and resilience in a helmet raises the question of whether a 3D printed bicycle helmet could be designed for multiple impacts as opposed to just one. How the material deforms under load, or how it could be engineered to deform is something which flexibility might facilitate. Current helmets, which are designed to protect a cyclist’s head, are actually quite fragile. Flexible materials may be able to shift this inherent quality and produce an object which merges durability and safety together.

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Humans, Robots & Helmets: A Conclusion

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Project Evolution Overview

Why don’t cyclists cyclists like wearing helmets?

• Concerned about looking silly while wearing a bulky foam hat • Doesn’t fit properly • Can be hot to wear in summer

Why do these issues exist?

Low chance of percieved value = Lack of personalisation and correct fit + Intangibility of accidents

• EPS foam defines the majority of helmets on the market. • Expensive tooling forces generalised size ranges • Established methods of production have been proven as efficient

• Annoying to carry around • Easily damaged

Other Downsides

• Requires multiple materials to produce helmet • Adhesives complicate end of life

• Requires a high number of components • EPS helmets are fragile

Could the bespoke production abilities of additive manufacturing be used to create a helmet?

Benefits • Facilitates the ability to produce one off items • Supports a greater range of geometries and structures

Concerns • Can the material effectively absorb impacts? • Can the weight to absorption ratio match EPS?

How can additive manufacturing address the issues?

• Dedicated locking function

• Design for disassembley

• Highly ventilated • Reduced bulkiness • Integrated components

• Design for durability • Single material simplified design • 3D scanned head to ensure excellent fit

• Cost

How do the requirements of printing process influence the helmet?

• Hollow structure is needed to reduce weight • Material needs to be removed from the internal voids

• End material needs to be durable and withstand the elements • Highly capable of producing complex geometry

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Conflicted Relationships

The bicycle helmet is an object which a great deal of cyclists have a conflicted relationship with. In many ways, it is an object which is completely logical since in theory it is an added layer of protection for oneâ&#x20AC;&#x2122;s skull in the event of a crash. It has been discovered, however, that the likelihood of a cyclist tangibly perceiving the effects of a bicycle crash to be low. The noticeable risks of crashing recede behind what is a much more apparent set of experiences that occur through wearing a helmet. As opposed to debating the efficacy of bicycle helmets, this project works within the existing helmet legislation present across Australia. It instead works to uncover the reasons cyclists are reluctant to wear helmets. Bicycle helmet design often attempts to balance the functional requirements of safety along with considerations for a cyclistâ&#x20AC;&#x2122;s needs while they are riding without incident. Comfort, fit, and style are all features which contribute to the success of the object, yet what remains questionable is the degree of balance achieved in helmets existing on the market today.

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The Urban Cyclist

There are numerous cultures and behaviours within cycling communities. These characteristics are largely driven by the context in which cycling occurs. This project has identified the urban or city cyclist as a category of rider which has not been adequately considered. The level at which a city influences the act of cycling is immense and complex. Since the majority of helmets have been designed for road racing, mountain biking, or extreme sports, there is yet to be a truly defined product category for the city, and in this projectâ&#x20AC;&#x2122;s case, Melbourne Victoria. Many helmets classed as urban helmets tend to rely heavily on existing styles and often equate to hybrid versions of existing helmets. Although they may address some of the fundamental requirements of city cyclists, how well they address them is highly dictated by the way most helmets are made, and more importantly what they are made from.

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Breaking the Mould

Expanded polystyrene has become the standard for most bicycle helmets available today. The ability of EPS to absorb energy, combined with its lightness and cost effective manufacturing, makes clear the reasons bicycle helmets continue to be manufactured in the material. This convention does however come with limitations, one of which is primarily a result of constraints within established methods of production. Research carried out through the process of designing a traditional bike helmet is strongly influenced by the characteristics of the end material and production process. This has formed a significant motivation for the project to venture outside such a contained field of research and attempt to rethink the helmet from its core with a strong focus on the people who wear them. Processes such as 3D scanning and 3D printing have the potential to substantially shift ways of approaching bicycle helmet design. By questioning many of the existing conventions, this project has identified several oversights in relation to the experiences of a city cyclist. It has done so in a way which also considers how to make the best use of technologies that designers now have increasing access to.

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Ways of Working

The project has documented the process of the development of a new and propositional helmet design. It is comprised of several individual features which each specifically address oversights discovered through observational research. Considerations regarding sustainability, comfort, fit, personalisation and methods of production all come together to form a single helmet design. The primary method of addressing cyclists’ reluctance to wear helmets, has been responded to through the application of 3D scanning. By customising the fit of the helmet specifically to a riders skull, a level of personalisation and comfort is added to the object. This process also allows a significant amount of the helmet’s visual bulk to be reduced and thus aims to decrease cyclists’ concerns over image. 3D printing allowed the helmet to develop as a single material shell. This proposes methods of improving the sustainability in helmet design through the integration of all necessary fasteners and features. The helmet’s bill of materials has decreased dramatically in the required number of components and range of materials. Finally, the helmet displays methods of designing with new manufacturing technologies that are rapidly developing in industry. Rather than relying on conventional approaches to the design of a helmet, this project explores how additive manufacturing can influence the physical nature of the object.

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Outcomes & Significance

The designed artefact acts as a packaged representation of the projectâ&#x20AC;&#x2122;s entire work, and does not attempt to act as a viable helmet for immediate production. Each of the designed features encompass ideas which form foundations for extending research within this field. Methods of scanning, ways of utilising scanned data, engineered and topologically optimised internal support structures, material testing, design automation and the possibilities surrounding the use of flexible materials have been outlined as areas for further research. The overall viability of the project at this stage is relatively challenging. The high cost and time investment involved in manually developing such a concept make it extremely inefficient. However, as additive manufacturing progresses, this bespoke and customised one off production has the opportunity to reach higher levels of manufacturing viability. The most fundamental aims of the project have been to uncover some of the reasons city cyclists are reluctant to wear helmets, form responses to the issues, and demonstrate how additive manufacturing can influence or enable the effective design of bicycle helmets. Cycling is a highly beneficial and enjoyable way of moving within a city. It is hoped that this research can be used to outline ways of more positively influencing the relationship cyclists have with their helmets, and therefore cycling itself.

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â&#x20AC;&#x2DC; Cycling is a highly beneficial and enjoyable way of moving within a city. It is hoped that this research can be used to outline ways of more positively influencing the relationship cyclists have with their helmets, and therefore cycling itselfâ&#x20AC;&#x2122;

Appendix

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Photo Study: Locked Helmets

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Image Index:

1. Cyclist taking off at the lights (Page 11) 2. Tailing a car (Page 13) 3. Bikes locked on the bridge (Page 17) 4. Extruder of 3D printer (Page 19) 5. Bike lane (Page 29) 6. Road helmet & head overlay (Page 39 7. Inside of an EPS shell (Page 41) 8. Vents of a road helmet (Page 43) 9. Melbourne helmet & head overlay (Page 44) 10. Melbourne helmet autopsy (Page 47) 11. Locked helmet hanging (Page 48) 12. Interlocked card detail (Page 51) 13. FDM infill patterns (Page 52) 14. Weighing the Melbourne helmet (Page 55) 15. Drop test rig (Page 56) 16. Recording the drop test (Page 58) 17. Video frames of impact - 4 frames (Page 59) 18. Crushed 12.5% sample (Page 60) 19. Crushed sample range (Page 61) 20. 3D printing structure samples (Page 63) 21. Artec 3D scanner (Page 65) 22. 3D printed scale model of scan (Page 66) 23. Compressed hair net (Page 69) 24. Rendered scan (Page 70) 25. Printing a test (Page 72)

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26. Testing the fit of the inner surface (Page 73) 27. Assembling a card model (Page 76) 28. Assembled card model (Page 77) 29. Experimental infill drawings (Page 79) 30. Helmet strap comparison (Page 81) 31. KUKA robot CNC foam (Page 82) 32. Machined foam prototype in block (Page 84) 33. Foam helmet shell (Page 85) 34. Iterations of clip prototypes (Page 88) 35. Final clip prototype with strap (Page 89) 36. 3D printing clip set (Page 90) 37. Cutting foam rebates (Page 90) 38. Stitching strap loops (Page 90) 39. Completed foam prototype (Page 90) 40. Foam prototype side profile (Page 91) 41. Foam prototype front view (Page 91) 42. First padding prototype sections (Page 93) 43. Assembled padding prototype (Page 93) 44. Installed neoprene 1 (Page 94) 45. Installed neoprene 2 (Page 94) 46. Venting iteration drawing (Page 97) 47. Laser cut hole patterns (Page 98) 48. Foam lock test (Page 101) 49. Final printed helmet section (Page 103) 50. Section hole pattern (Page 104)

51. Section padding detail (Page 104) 52. Section clip detail (Page 104) 53. Section strap installed detail (Page104) 54. Section structure detail (Page 105) 55. Smoke airflow test (Page 106) 56. Helmet on print bed (Page 109) 57. Detail of raw helmet print (Page 110) 58. Dyeing the helmet (Page 113) 59. Rinsing the helmet (Page 114) 60. Clamped neoprene cut guides (Page 115) 61. Completed neoprene cut (Page 115) 62. Installing neoprene pads (Page 115) 63. Installed neoprene pads (Page 115) 64. Side profile of final helmet (Page 117) 65. Ghosted overlay comparison (Page 123) 66. 4 views of final helmet (Page 125) 67. 300g printed helmet (Page 126) 68. Simplified components (Page 127) 69. Helmet hanging from bars (Page 128) 70. Rear face of helmet (Page 129) 71. Inside of helmet (Page 130) 72. Side of helmet with straps (Page 131) 73. Locked final helmet (Page 132) 74. Locked detail (Page 133) 75. Airflow user test (Page 134)

76. Helmet on cyclist (Page 135) 77. Attempting to bend the helmet (Page 137) 78. Research futures map (Page 138) 79. Additive structure example (Page 140) 80. Local bike store (Page 143) 81. Wireframe scan drawings (Page 145) 82. Supported helmet print (Page 147) 83. Flexing the sample print (Page 149) 84. Helmet on ledge (Page 151) 85. Adjusting helmet on head (Page 159) 86. Organised helmet components (Page 161) 87. Series of helmets locked to bikes (Page 167)

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Glossary of Terms

ABS - Acrylonitrile butadiene styrene: a common thermoplastic often used as filament for desktop 3D printers. PLA - Polylactide: a starch based thermoplastic and renewable resource filament for desktop 3d printers. EPS - Expanded Polystyrene: a common thermoplastic foam material used in bicycle helmets along with many of other packaging and insulating products. Additive Manufacturing - A method of creating 3D objects by incrementally printing 2D layers to form a final object. There are numerous variations within the technology but the term additive manufacturing covers all types of 3D printing. SLA - Stereolithography: an additive manufacturing process which uses a photo sensitive liquid resin which is cured through exposure to UV laser. SLS - Selective Laser Sintering: an additive manufacturing process which fuses powdered material together with a laser. FDM - Fused Deposition Modelling: an additive manufacturing process which extrudes layers of melted plastic through a heated nozzle. It is the most common type of additive manufacturing seen within the consumer desktop 3D printer market. Build Platform - Refers to the surface of a 3D printer where the 3D object is manufactured. The build platform determines the maximum printable area of any printer and thus determines the maximum object size. Printers have a maximum size for the X, Y and Z axis of the machine.

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Point Cloud - A term typically used to describe raw 3D scanned data. Points are defined by X,Y and Z coordinates and digitally represent a scanned 3D object. The more points recorded results in a model of higher detail or resolution. NURBS - Non-uniform Rational Basis Spline: a type of mathematical curve commonly used within 3D modelling programs such as Rhinoceros. These are highly accurate splines which are also flexible and often used to represent more organic forms as opposed to geometric shapes. Polygon Mesh - A type of 3D file which is used to define the shape of objects. It is a collection of vertices, edges, and faces, which primarily form triangles within X, Y and Z coordinate systems. These meshes are typically the final file type to be output to 3D printing software. Parametric - A type of 3D modelling which is driven by a set of parameters. These 3D models are typically defined by dimensions or numbers and allow them to be generated or modified through potentially complex algorithms. This type of modelling is beneficial for applications which require flexibility in the final outcome. Grasshopper - A visual programming language developed by David Rutten at Robert Mcneel & Associates. The program runs as a plugin for Rhinoceros and is a visual method of assembling generative algorithms.

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Bibliography

Attewell, R. G., Glase, K., & McFadden, M. (2001). Bicycle helmet efficacy: a meta-analysis. Accident Analysis & Prevention, 33(3), 345-352. doi: http:// dx.doi.org/10.1016/S0001-4575(00)00048-8

Runyan, C. W., & Runyan, D. K. (1991). How Can Physicians Get Kids to Wear Bicycle Helmets? A Prototypic Challenge in Injury Prevention. American Journal of Public Health, 81(8), 972-973.

Curnow, W. J. (2003). The efficacy of bicycle helmets against brain injury. Accident Analysis & Prevention, 35(2), 287-292. doi: http://dx.doi. org/10.1016/S0001-4575(02)00012-X

Coron, J. J., McLaughlin, G. G., & Dorman, S. M. (1996). Factors influencing use of bicycle helmets among undergraduate students. Journal Of American College Health, 44(6), 294-297.

Curnow, W. J. (2006). Bicycle helmets: Lack of efficacy against brain injury. Accident Analysis & Prevention, 38(5), 833-834. doi: http://dx.doi. org/10.1016/j.aap.2006.04.007 Fyhri, A., Bjørnskau, T., & Backer-Grøndahl, A. (2012). Bicycle helmets – A case of risk compensation? Transportation Research Part F: Traffic Psychology and Behaviour, 15(5), 612-624. doi: http://dx.doi.org/10.1016/j.trf.2012.06.003 Cameron, M. H., Vulcan, A. P., Finch, C. F., & Newstead, S. V. (1994). Mandatory bicycle helmet use following a decade of helmet promotion in Victoria, Australia—An evaluation. Accident Analysis & Prevention, 26(3), 325-337. doi: http:// dx.doi.org/10.1016/0001-4575(94)90006-X Rezendes, J. L. (2006). Bicycle Helmets: Overcoming Barriers to Use and Increasing Effectiveness. Journal of Pediatric Nursing, 21(1), 35-44. doi: http://dx.doi.org/10.1016/j. pedn.2005.06.005 Lajunen, T., & Räsänen, M. (2001). Why teenagers owning a bicycle helmet do not use their helmets. Journal of Safety Research, 32(3), 323-332. doi: http://dx.doi.org/10.1016/S0022-4375(01)00056-1

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O’Callaghan, F. V., & Nausbaum, S. (2006). Predicting Bicycle Helmet Wearing Intentions and Behavior among Adolescents. Journal of Safety Research, 37(5), 425-431. doi: http://dx.doi. org/10.1016/j.jsr.2006.08.001

Wood, T., & Milne, P. (1988). Head injuries to pedal cyclists and the promotion of helmet use in Victoria, Australia. Accident Analysis & Prevention, 20(3), 177-185. doi: http://dx.doi.org/10.1016/00014575(88)90002-4

Thompson, N. J., Sleet, D., & Sacks, J. J. (2002). Increasing the use of bicycle helmets: lessons from behavioral science. Patient Education and Counseling, 46(3), 191-197. doi: http://dx.doi. org/10.1016/S0738-3991(01)00212-9

HALL, L. A.-H. A. F. L. Research Design Insights from a Survey of Urban Bicycle Commuters. Paper No. 98-0156.

Kakefuda, I., Stallones, L., & Gibbs, J. (2009). Discrepancy in bicycle helmet use among college students between two bicycle use purposes: Commuting and recreation. Accident Analysis & Prevention, 41(3), 513-521. doi: http://dx.doi. org/10.1016/j.aap.2009.01.014 Giles, A. R., Strachan, S., Stadig, G., & Baker, A. C. (2010). ‘Don’t be scared, you don’t have to wear your lifejacket’: using the theory of planned behaviour to understand lifejacket usage in Tuktoyaktuk, Northwest Territories, Canada. The Polar Record, 46(4), 328-335. doi: http://dx.doi. org/10.1017/S0032247409990180 Zamani-Alavijeh, F., Bazargan, M., Shafiei, A., & Bazargan-Hejazi, S. (2011). The frequency and predictors of helmet use among Iranian motorcyclists: A quantitative and qualitative study. Accident Analysis & Prevention, 43(4), 1562-1569. doi: http://dx.doi.org/10.1016/j.aap.2011.03.016 Pucher, J., Garrard, J., & Greaves, S. (2011). Cycling down under: a comparative analysis of bicycling trends and policies in Sydney and Melbourne. Journal of Transport Geography, 19(2), 332-345. doi: http://dx.doi.org/10.1016/j. jtrangeo.2010.02.007

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