Mimosa Pudica Runda Aduldejcharas Camila Becerra Ploy B. Boonthongrungtawee Marcella Carone
Emtech 2015-1016
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COURSE DIRECTOR Michael Weinstock George Jeronimidis
STUDIO MASTER Evan Greenberg
TUTORS
Elif Erdine Manja van de Worp
FACILITY
DPL - Angel Lara-Moreira
Biomimetics Emergent Technologies & Design 2015-16
ABSTRACT
Our aim was to understand the biologic explanation behind Mimosa Pudica sensitive comportment and translate some of principal characteristics to a material system. The project’s focus was to develop a system activated by an external local stimulation that transforms the global organization. During 3-week workshop, we went through a series of form and material experiments that could reach the expected behavior. The main exploration was on flexible materials and its properties. Rubber, Latex, springs and nitinol springs were tested and its possible combinations with plywood and polypropylene. All global investigations were thought as a combination of components and its possible interaction. In order to achieve these relations, during the whole process, we regard special attention to joinery design. Relating to outer stimulation, all the tests were submit to temperature changes and their alteration in a variety of conditions. For our project, not only the system activator was significant, but also the system recovery to the initial shape. Thought physical and digital experimentation, we could map the principal variables for each experiment and combine then to a better solution. In addition, digital analysis guided us to understand the limitation of each test in specific conditions.
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INTRODUCTION PRINCIPAL CONCEPTS LOGIC DEVELOPMENT MATERIAL EXPERIMENTATION PHYSICAL AND DIGITAL FORM FINDING FLEXIBILITY EXPERIMENTATION INFERENCES REFERENCES
1 2-5 6-7 8-9 10-13 14-18 19 20
Biomimetics Emergent Technologies & Design 2015-16
INTRODUCTION
Plants are generally considered motionless organisms. However, certain species can react in response to environmental changes. This is the case of Mimosa Pudica, a sensitive plant that folds its leaves and steams while exposed to an external stimulus as touch, temperature, vibration and sunlight. The fascination about Mismosa Pudica movement rests in how fast a plant structure, without muscles, can react. Our project was divided in two parts in order to understand Mimosa’s behavior and its biological system characteristics that could be applied to a material system. The first part is the biological investigation to comprehend Mimosa’s morphology and how a plant structure can rapidly react to an external stimulus. We run a series of experiments with a real Mimosa to understand how a variety of stimulation could affect the plant and how these movements occurs in cell and global scale. On the second part, we constructed our form finding discourse based on the differentiation of pressure that Mimosa cells’ have to change its shape. In our research, this concept was interpreted to create movement and curvature. The Logic development was built on the hierarchical process, global scale exploration and the relation between local and global reactions. Though a variety of material and form experiments, based on physical and digital models, we understood how the relation between biology and material exploration can be reach and evolve though a series of tests. Our final investigation is the combination of all tested experiments during the workshop process.
Biomimetics Emergent Technologies & Design 2015-16
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MIMOSA PUDICA Mimosa Pudica is a sensitive plant native from Central The following factors influence and South America but it can be also found in some Mimosa’s reaction; touch, sunlight, countries in Asia. temperature and vibration When the plant is exposed to an external stimulus as Touch touch, sunlight, temperature or vibration, it reacts by With little contact, sequence folding its leaves and, depend on the stimulation intensity, movement can be seen. it steam as well. The whole reaction occurs as rapid movements and this Sunlight was our focus in this project. The plant open at sunrise and fold up at sunset, known as “Nyctinastic movement.”
Temperature The plant opens at optimum temperature (21 Co - 24 Co), high temperature will trigger the leaves to close.
Vibration
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The plant is also very sensitive when it is shaken. Figure 1: mimosa pudica
SEQUENCE OF MOVEMENTS
STIMULUS
Figure 2: section of mimosa pudica
Biomimetics Emergent Technologies & Design 2015-16
STIMULUS AND HIERARCHY The fascination about Mismosa Pudica movement rests in how fast a plant structure, without muscles, can react. The reaction is explained by Mimosa Nastic structure and its mechanics without muscles. In other words, the system is driven by pressure differentiation inside the cells, called turgor pressure. The mechanism can change stiffness in leaves and petioles and consequently provoke it fold reaction.
The system is activated by an external stimulus and the hierarchy of movements is one of the goals that we try to achieve in our biomimetics project. The stimulus is transmitted cell by cell, activating osmosis process and Calcium exchange between its membranes. Its clearly an hierarchy process, that starts on leaves and then petioles. Pulvini and Pulvinus, respectively.
external stimulus rapid movement
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reversible slow recovery
PULVINUS AND PULVINI MORPHOLOGY The diagram A represents pulvinus morphology and how osmosis process works in order to change plant stiffness and cause its flexure. The blue gradient symbolises cells size before and after stimulation. Darker blue signifies bigger cells and the maximum turgor pressure in the system.
middle of the pulvinus and after osmosis they are concentrated in the top part (diafram B). The reaction in extremely fast, however the recovery process is slow. Pulvini Morphology presents the same pressure system and can be seen in diagram C.
Before stimulus, they are concentrated in the
Biomimetics Emergent Technologies & Design 2015-16
before stimulus
after stimulus
4 Figure 3: Pulvinus morphology
before stimulus
after stimulus
Figure 4: Pulvinus simplified cross-section
Figure 5: Pulvinus morphology
Biomimetics Emergent Technologies & Design 2015-16
TEMPERATURE Temperature is one of the main factors for leaves to open or close. Therefore, we experiment with real plant to see the range of temperature that the plant can react with heating. When it lost too much water, it starts to wilt and die. Angle
15 Co
20 Co
25 Co
30 Co
DIE
5 0
15 20
25
30
35
40
45 Co
Figure 6: Mimosa Pudica response to temperature
SUNLIGHT
35 Co
40 Co
Figure 7: Mimosa Pudica response to temperature
Mimosa leaves start to open at 9.00 AM and close at 18.00 AM. Light one factor for leaves open or close. Angle
9.00
0
6.00 9.00 12.00 15.00 18.00 21.0024.00 Time
Figure 8: Mimosa Pudica response to sunlight
18.00
15.00
21.00 Figure 9: Mimosa Pudica response to sunlight
35 C Biomimetics Emergent Technologies & Design 2015-16
TENSEGRITY The goal on this first experiment was to extract the principle of Mimosa Pudica and design the structure. The idea of tensegrity is implemented because of its dynamic behaviour, which is similar to Mimosa Pudica. Rubber band and spring are chosen to be experiment, as these materials are elastic. “Tensegrity is a principle based on self-stressed and autostable structures composed by isolated components in compression inside a net of continuous tension, in such a way that the compressed members (usually bars or struts) do not touch each other and the prestressed tensioned members (usually cables or tendons) delineate the system spatially.� [1]
6 Figure 10: Tensegrity experiment 1
FORCE
COMPRESS
EXPAND Figure 11: Tensegrity experiment 2
Biomimetics Emergent Technologies & Design 2015-16
LOGIC DEVELOPMENT We understand the system behavior in cell scale, although we found more interesting to focus our project on global scale research and the relation between local and global response. We based our speech on the differentiation of pressure to create movement and curvature. In our view, the turgor pressure logic could be translated to a system by the utilization of flexible material and its recovery characteristic. During the process, we test a range of materials that could have the expected behavior.
the hierarchy process, when a local change can induce a global transformation. One of the main research in this field was focused on the Hoberman sphere and its local and global reaction. All the nodes are interconnected and the system is based on scissor joints, consequently, any local modification can be seen in the whole shape.
The other principal focus of development was Logic Diagram
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change pressure between two sides – create movement/ curvature material with flexibility and reversability
Figure 13: Logic experiment
Hoberman sphere research
Figure 14: Hoberman sphere
Biomimetics Emergent Technologies & Design 2015-16
MATERIAL EXPERIMENT The purpose is to experiment with 4 materials with expansion propierties to develop a flexible joint.
MATERIAL
NORMAL SPRING
NITINOL SPRING
LATEX
RUBBER BAND
1MINIMUM STRETCH
2 cm.
3 cm.
8 cm.
8.5 cm.
MAXIMUM STRETCH 2
8 20 cm.
22.5 cm.
16 cm.
30 cm.
RESULT OF RECOVERY
3 Figure 20: Materials comparison pictures
++ Easy to contracts and expands
++ Return to the original size ++ It is activated by heat
++ Return to the original size ++ Expands twice the original size
++ It is the material with larger expansion (30 cm)
-- Not return to the original dimension
-- Difficulties to expand without sufficiently cold temperature
-- The material is worn after long use
-- Difficulties to control
Biomimetics Emergent Technologies & Design 2015-16
NITINOL EXPERIMENT
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Temperature Time
STAGE 1
STAGE 2
STAGE 3
27.2ยบC Temperature 01:00:00 Time
36.5ยบC Temperature 01:13:03 Time
48.5ยบC 00:32:02
no deformation
slow deformation did not return to initial position
rapid deformation return to initial position
QR Code 1: Nitinol Springs Experiment Biomimetics Emergent Technologies & Design 2015-16
SPINE EXPERIMENT PHISYCAL AND DIGITAL FORM FINDING The spine experiment come from the relation between digital and physical form finding. The spine form allow movements that occurs in local scale and affects the whole system. Bending and twisting were the main two actions that we were concentrated. Just by moving one piece, the system can reach different shapes and curvatures. To help us to discover the system limits, we develop a digital model that could reproduce accurately the behavior that we attained physically. We run a series of analysis to understand how curvature was achieved and which variables we could change to achieve different results. Number and size of the pieces, the space between then, how the joints are designed where our principal attention on this experiment.
CURVATURE ANALYSIS 10 Curve
Plan
Perspective
Curvature Analysis Negative gaussian curvature Zero gaussian curvature Positive gaussian curvature
Figure 18: Curvature analysis
Biomimetics Emergent Technologies & Design 2015-16
DESIGN DEVELOPMENT
Three designs are proposed to achieve the best shape for plywood to construct the model. From experiment, Design 1 gives the best flexibility to twist when attached one end to the nitinol spring. Design 2 is the most stable when attaching plywoods together in this case, where glue cannot be used, as it will reduce flexibility of the whole model. Design 3 tells us that the design at both end where the rubber band will be attached in later development is in good shape, but is not strong enough and can be broken easily.
Figure 16: Strip experiment comparison pictures
Therefore, by picking up the advantage of three designs, the final design is constrcuted.
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2 cm
15o
Design 1
1 cm
0.2 cm
10o
Design 2
<1o
Design 3
2 cm
5o
Final design
Figure 17: Strip experiment comparison diagrams Biomimetics Emergent Technologies & Design 2015-16
DESIGN DEVELOPMENT This design starts from a linear global shape. The strips are crossed to one another. The model can be manipulated by using nitinol spring. When spring was heated, the spring compact forcing another strip to move closely to one another.
Nitinol Spring the heat caused the spring to compress and release
Joint the linear form created by the wooden strips joinging together
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MODEL SIZE: (mm) 200 x 200 x 500 Figure 19: Design development 2
Biomimetics Emergent Technologies & Design 2015-16
DESIGN DEVELOPMENT From the experiment with real plant earlier, we understand that temperature has great effect to the Mimosa Pudica. Therefore, heat and temperature were chosen as a factor to make model become dynamic. Nitinol is the common name used for the shape memory alloy Nickel Titanium. The temperature changed when heated will result in transforming the spring to compress. Rubber band the rubber allows the flexible freeform
Nitinol Spring the heat caused the spring to compress and release
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Joint the linear form created by the wooden strips joining together
MODEL SIZE: (mm) 200 x 200 x 500 Figure 15: Design development 1
Biomimetics Emergent Technologies & Design 2015-16
ROTATION MECHANISM In this phase we want to develop the project further, by testing materials properties. We explore many logic; rotating mechanism, twisting mechanism, scissor joint and another one completely unrelated to the model. This first design is based on the rotation logic. The goal of this logic is to test material to see the material property. The 3D module is designed by assembling 3 module that are orientated at different angles. 4 flexible materials are chosen to locate in this model which are normal spring, nitinol spring, rubber band and resin. These material have advantages and disadvantages as follow. The normal spring has elastic property to a certain limit. However, once the spring is stretch pass its elastic limit, the spring behave plasticly which means the spring does not return to its original shape. While Nitinol spring can be contracted by heat but it has to be expand manually. The main drawback for rubber band is its melt and break when heated. Lastly, the resin which can be done by 3D printing allow 3 joints to be connected, but it is too soft and fragile.
14 Joint flexible joints- 3 ways to combine wooden strips
Module
module system, controlling by the spring - allow the strips to rotate
3D Module Figure 21: Rotation mechanism diagram
combine the module in 3 sides and use nitinol spring to control the system
Normal spring
Nitinol spring
Rubber band
Resin
++ bounce back quickly -- no recovery if stretch into a maximum strength
++ control by heat -- manually expand/ pull
++ bounce back quickly -- heat will break and melt the rubber
++ allow the component to join from 3 angles -- it is very soft/ break easily Figure 22: Material comparison
Biomimetics Emergent Technologies & Design 2015-16
TWISTING MECHANISM For the twisting logic, we developed the logic from the rotating mechanism. The joints have been developed to be more flexible from the previous mechanism. When one side of the nitinol spring is heated the spring contracted forcing the other end to expand, in which the two springs are connected by thin wire. This makes the turbines rotate and move downward. Turbines Principal stimulus. Temperature in the springs. Can be applied in windy condition.
Nitinol Spring the tri-joint allow the pieces to twist
15 Turbines the wooden strip connected to plastic, allows the strips to move freely
Nitinol Spring the controlling point of the action. When the spring compress the module twist and move downward. When the sping expands, the module twist and move upward
MODEL SIZE: (mm) 400 x 800 x 50
Figure 23: Twisiting mechanism diagram QR Code 2: Twist Experiment Biomimetics Emergent Technologies & Design 2015-16
SCISSOR MECHANISM In this configuration, the pieces are superimposed to generate movement, and to create a global form must have a vertical and horizontal joint. The movement of a pattern reacts in a global and creates a system. The pattern is made of individual pieces of rigid material (plywood) with flexible joints (plastic). The patterns are connected by overlapping the pieces of plywood through a screw and nut.
There are 4 major components, these are arranged in a way that work as a system, having a local movement they have a simultaneous reaction and the model react in a global shape
++ Create flexible joints ++ Able to easy change system shape -- Difficulties to control transformation -- System free to move in multiple directions Figure 26: Scissor joint sequence pictures
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FLEXIBLE COMPONENT MECHANISM Our last experiment had a different target. Rather than flexible joints, our research was based on flexible components and its possible deformation as local and global scale. We added 3 nitinol springs as actuators to test a dettached piece. The results were what we got in previous digital experiments. However, the polypropylene used as flexible component material started to melt after some temperature tests. In addiction, for the global shape, the boundary conditions were ignored in this experiment. We believe that the experiment should be developed with different flexible materials, resistant to heat. With correct boundary conditions control, it could be used as a temperature responsive facade or canopy. SPRING 1
SPRINGS 1 AND 2
SPRINGS 1, 3 AND 3
TOP VIEW
NO DEFORMATION
ELEVATION VIEW
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Figure 24: Flexible component diagram
Normal springs Nitinol springs
MODULE SYSTEM +By increasing temperature, nitinol springs start to contract. +Module system, can be applied to wall system for natural ventilation and shading temperature stimulation +Component can double its high - 8 to 16 cm Once connected, a local transformation can be seen in the whole system - Polypropylene is the wrong material for this experiment once it melts when exposed to high temperatures
QR Code 3: Flexible Component Experiment
Biomimetics Emergent Technologies & Design 2015-16
COMPONENT DEFORMATION ANALYSIS The component has 3 beams connecting the vertices, these beams are the nitinol springs. The flexible surface can easily change shape, when heat is applied to the nitinols springs it changes its size and the flexible surface can easily change the shape. The experiment shows the deformation (compression and expansion) of the component when the enviromental temperature is between 10 ° C and 40 ° C
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Figure 25: Strand analysis
Biomimetics Emergent Technologies & Design 2015-16
CONCLUSION
During Biomimetics workshop our aim was to achieve a responsive material system that could be activated in a local scale and produce a global organization change. To reach this objective, we run a sequence of experiments that comprise either flexible joints or flexible materials to create movement. However, once we were focus just on the flexibility characteristics of tested materials and its possible combinations, in the end of the workshop we realized that the global form evolution were lost between each experiment. Thought digital and physical explorations, we clearly understood the variables and limitations in each particular system, but we could not be able to evolve all characteristics in a final test. Our final experiment with nitinol springs and polypropylene were design to understand the behavior of a flexible material rather than a flexible joint. Once it was our first experiment with this idea, we noticed many mistakes. Firstly, the polypropylene started to melt when we applied direct heat to the nitinol springs, showing that this is not the correct material combination. Secondly, boundary conditions were not specified in order to control transformations. This last experiment comprises just a â&#x20AC;&#x153;pictureâ&#x20AC;? of how the whole system can be. After a series of material flexibility and reversibility investigations, we decided that Nitinol springs were the best translation for Mimosa behavior. Nevertheless, during many experiments we just could have the instruments to heat Nitinol and compress the springs. The opposite procedure could be achieved by the rapidly change to significant lower temperatures. Consequently, we assumed that the scalability of a system with Nitinol springs is considerably limited. In other hand, once all the experiments are component based, if we develop a new activator, it will be easily translated to a bigger scale. To conclude, the workshop was important for us to comprehend that, in order to achieve a solution closer to our goal, the process and all the experiments should have a principal line of though more defined. It was important to understand this and take a step back to progress Mimosaâ&#x20AC;&#x2122;s based system in Core I. For further developments, we will focus on scissor joints behavior and its capability to be locally activated and globally changed.
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Martone, P. (2010). Integrative & Comparative Biology. Integrative and Comparative Biology, 50(5), 889-907. doi:10.1093/icb/icq122 Braam, J. (2004). In touch: Plant responses to mechanical stimuli. New Phytologist, 373-389. Cohen, Y. (2006). Biomimetics: Biologically inspired technologies (pp. 473-491). Boca Raton, FL: CRC/Taylor & Francis. Allen, R. (1969). Mechanism of the Seismonastic Reaction in Mimosa pudica. Plant Physiology, 1101-1107. Cohen, Y. (2012). Biomimeics Products. In Biomimetics: Nature-based innovation (pp. 377-429). Boca Raton: CRC Press. Menges, A. (2015). Fusing the Computational and the Physical: Towards a Novel Material Culture. 85(5). doi:10.1002/ad.1947
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Figure Reference Figure 1: Mimosa Pudica UF/IFAS Center for Aquatic and Invasive Plants. (n.d.). Retrieved January 5, 2016, from https://plants.ifas.ufl.edu/ plant-directory/plant-line-drawings/
Figure 3: Pulvinus morphology “Bio-inspired design of intelligent materials”, Proc. SPIE 5051, Smart Structures and Materials 2003: Electroactive Polymer Actuators and Devices (EAPAD), 54 (July 28, 2003); doi:10.1117/12.484425; http://dx.doi.org/10.1117/12.484425
Figure 4: Pulvinus simplified cross-section “Bio-inspired design of intelligent materials”, Proc. SPIE 5051, Smart Structures and Materials 2003: Electroactive Polymer Actuators and Devices (EAPAD), 54 (July 28, 2003); doi:10.1117/12.484425; http://dx.doi.org/10.1117/12.484425
Figure 11: Tensegrity experiment 2 Gomez-Jauregui, V., Tensegrity structures and their application to Architecture, Univesidad de Cantabria, Publishing service, Santander, 2010
Figure 14: Hoberman sphere Preschool. (n.d.). Retrieved January 5, 2016, from http://www.kaleidoscopescience.com.au/pre-school/
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