Meeting industry needs Managing the integrity of engineered assets – to achieve operational excellence, maximum performance and the highest safety and environmental standards, while simultaneously minimising costs – is complex and challenging for today’s industrial operators. In response to this, TWI offers world-leading asset integrity management services based on more than 50 years of accumulated experience in engineering R&D, deployment and consultancy. Over 150 engineers, technicians and consultants work in collaboration to conceive and implement asset integrity management strategies designed to avoid engineering failure, ensure compliance and optimise operating and maintenance expenditure. We offer a full range of services including tailored inspection, component testing and failure investigation. Using our state-of-the-art laboratories, we provide mechanical and non-destructive testing for structures and components of all shapes, sizes and specifications, in ambient and aggressive environments. We continue to invest in new equipment and facilities in order to exploit the opportunities provided by evolving technologies and processes. As an Industrial Member company of TWI, you can draw on our multi-disciplinary teams of experts for independent and impartial advice and solutions to technical issues. We undertake single client projects as well as joint industry projects where several Member companies join forces to address a particular industrial or sector-based issue. TWI sits on many European and international standards committees, giving us a unique insight into the dynamic needs of industry. Our integrity management services are utilised across major industries including oil and gas, aerospace, nuclear, defence, wind energy, power, automotive, rail and construction.
Advanced non-destructive testing TWI provides advanced and conventional non-destructive testing (NDT) services for the inspection of structures, both on and off-site, including pipelines, storage tanks, risers, rail tracks, ship hulls, wind turbines and more. We develop and optimise inspection systems to meet industry needs and our field services are in demand worldwide. Our expertise includes developing techniques and procedures for: array ultrasonic methods such as phased array and full matrix capture; long-range guided wave methods; digital radiography; eddy current arrays; and electro-magnetic acoustic transducer based methods. In addition, we have developed a method for long-term testing of polyethylene pipe joints. TWI can also help review inspection procedures for clients from across all industry sectors and provide an independent critical assessment. Where required, we can generate novel techniques to meet pre-determined criteria as well as formulate and implement new procedures.
Non-destructive testing for additive manufacturing We undertake X-ray computed tomography (XCT), a powerful non-destructive testing technique highly suited to additive manufacturing (AM) part inspection, for clients in our own laboratories. It provides volumetric 3D density data on the entire internal structure of the scanned object and can output detailed, 2D crosssectional images. Alternatively, we can deploy ultrasonic techniques on large additive manufactured parts and during manufacture on site. Surface defects can be reliably detected using eddy current inspection and dye penetrant techniques.
Robotics and automation TWI’s 6-axis industrial robot system, for the automated inspection of complex geometries, deploys advanced ultrasonic testing sensors and can automatically inspect pre-programmed components in a fraction of the time it usually takes. As a result, we offer clients timely services in offline scan path planning using CAD input; pulse echo and through transmission; phased array and full matrix capture; and water squirts or full immersion. The system is scalable to suit component size and incorporates a full suite of acquisition and analysis tools with 3D data display. In exciting developments, we are now engineering wall-climbing and swimming prototype
NDT robots toward the final technology readiness levels and are on course to commercialise at least two robotic NDT systems. One mobile system will operate in oil and petrochemical storage tanks to detect corrosion and pitting on the floors and walls while submerged in liquids. The other will climb on wind towers to inspect blades using shearography.
Non-destructive testing product development We have a long history of new product development based on NDT research and collaboration with international industry partners. This combined knowledge and capability enables us to take NDT technologies to higher technology readiness levels (TRLs) and provide support for fast-track innovation, enabling pioneering new NDT products to reach commercial readiness and achieve market success. An example of this is TWI’s PolyTest™ – a portable system for the volumetric NDT of electrofusion and butt fusion joints in polyethylene pipe.
Clear ultrasonic imaging software Crystal™ by TWI is a real-time, versatile, ultrasonic, full matrix capture/total focusing method inspection software package. Built around a robust, scalable architecture, it can be deployed in a wide variety of industry scenarios from small-form-factor systems comprising a laptop and portable pulsar/receiver, through to factory solutions utilising rack-mounted hardware with support for up to three pulsar/receiver units. We provide services using TWI’s Crystal™ and it is also available to purchase separately.
Qualification and validation TWI’s qualified personnel provide help, advice and information on the complete testing qualification process, including selection of appropriate standards and codes, preparation of technical justifications and the manufacture of qualification trials specimens.
Third party inspection We undertake third party oversight in all NDT inspection techniques, overseeing levels of qualification up to EN 473 and ASNT NDT Level 3.
Condition and structural health monitoring TWI provides complete monitoring solutions for plant and components, helping companies and organisations to reduce inspection and maintenance costs, increase efficiency and improve safety and reliability. Structural health monitoring is concerned with the overall structure of assets, for example wind turbines, bridges, cranes and offshore platforms. Condition monitoring deals with machinery; mainly moving components such as gears and bearings as well as boilers and heat exchangers. The monitoring outputs provide owners and operators with objective and reliable data that shows any changes to the structure or component; an assessment can be made of its overall health and it provides a tool for safely extending useful life in the future. Unplanned shutdowns can therefore be avoided and the life expectancy of plant and machinery more accurately calculated.
Structural health monitoring Our structural health monitoring service involves observing a complete structure over time, periodically sampling response measurements from an array of sensors, extracting damage-sensitive features from the measurements and making a statistical analysis to determine current state of health. This process enables early intervention and may prevent catastrophic failure from corrosion, fatigue, or cracking. TWI’s Acoustic Emission Hydrogen Induced Cracking detection system (AEHIC) provides a means of identifying whether hydrogen induced cracking is going to occur, or is already in progress, including how it is evolving. The resulting information can then be applied to limit the potential for pipework damage or failure, giving greater control over a plant’s operation and performance. The Vibration Monitoring and Risk Analysis System for Process Piping (VARA) from TWI uses vibration analysis to detect structural damage. It gives operators vital data to inform their process piping maintenance strategy; providing a link between vibration analysis of pipework and the likelihood of the occurrence of fatigue crack initiation.
Condition monitoring Condition monitoring facilitates intervention in the early stages of machinery deterioration. We look at components on an individual basis, using a variety of different technologies such as acoustic emission or guided wave and vibration analysis, to gather data which can be analysed for signs of change. This is particularly beneficial for machines not suited to regular inspection access, such as offshore wind turbines or those in continuous service. We are currently developing digital twin technology for condition monitoring of wind turbines, building on our longstanding experience in the wind energy sector. A condition monitoring system encompasses the entire physical wind turbine, providing ongoing structural health analysis. Simultaneously, this is mirrored virtually using a 3D model of the wind turbine in the form of a digital twin, including input from different sensors positioned across the physical entity, to continually feedback monitoring data. The output is a fully comprehensive, real-time assessment of the structural condition of individual wind turbine assets. In the longer term, we will expand our application of digital twin technology into other industries.
Instrumentation and monitoring TWI has a substantial track record in the design and installation of instrumentation and data logging systems for the measurement of service-loading or stress histories. Client services include the design and application of monitoring systems; data recording such as during trial, hydro-tests and other services operations; and the analysis and interpretation of data. We have assessed a wide range of structures and components including pressure vessels, process plants and earth moving equipment.
Life-cycle assessment We help companies take a through-life-cycle approach to their assets and support run-inspect-repair-replace decision making. Our life-cycle assessment process addresses each asset as a system, taking into account environmental factors and long-time horizons, thereby helping clients to calculate component life-cycle costs.
The CrackFirstTM fatigue sensor system is an alternative method of monitoring steel welded structures for longterm fatigue usage. It enables the estimation of remaining fatigue life and the setting of usage-based inspection intervals. When attached adjacent to a fatigue-critical detail, the sensor responds to the cyclic loading, changing its output in proportion to the cumulative fatigue damage for a typical fillet welded joint. We can advise on the use of CrackFirst sensor systems for new structures or those already in service.
Risk based inspection TWI works with clients to develop inspection plans based on knowledge of the risk of failure of structures and equipment. We assess the likelihood of failure due to damage, deterioration or degradation and the consequences of such failure. The outcome is a costeffective inspection process, centred on the API 580/581 standards and safety compliance, which can be used with confidence for making risk-based decisions. Using an established methodology and TWI’s RiskWISE® software, we also develop tailored maintenance and replacement solutions and provide guidance on assess management, from individual component studies through to turnkey, plant-wide projects. TWI’s RiskWISE plant inspection and maintenance software is integral to our risk based inspection services and is also available to purchase separately.
Fitness-for-serviceassessment Our experts carry out fitness-for-service assessments, in accordance with API 579-1/ASME FFS-1, to determine the structural integrity of plant and equipment and judge its suitability for continued service. These incorporate fracture and fatigue management approaches such as designing to minimise failure; assessment of flaws; joint and structural performance assessment using TWI’s IntegriWISE® fitness-for-service software; and experimental and computational stress analysis. TWI’s IntegriWISE software is also available to purchase separately.
Engineering critical assessment Engineering critical assessment (ECA) uses fracture mechanics principles to determine the defect tolerance of structures or components due to brittle fracture, fatigue, creep or plastic collapse. Our engineers have in-depth knowledge of ECA codes (BS 7910 and R6) and provide a prompt and accurate response to fracture related problems. We use TWI’s fracture and fatigue assessment software CrackWISE®, developed in accordance with BS 7910, which is also available to purchase separately.
Corrosive environment testing TWI has specialist equipment for testing materials in corrosive environments such as the mooring chain test rig, with a 6000kN load capacity and a dedicated facility for fatigue endurance and fatigue crack growth tests in high-pressure gas. Many of our large and small-scale mechanical, fracture and non-destructive tests can be adapted to provide simulated service situations including sour (H2S) and sweet (CO2); brine; seawater; high pressure; and high or low temperature. Data from the tests we conduct provides designers and engineers with additional assurance of fatigue integrity before materials or components are exposed to cyclic loading.
Full-scale pressure testing We operate a purpose-built pressure pit test facility, designed, built and commissioned in-house, that can be used to test components up to 10m in length and weighing up to 10 tonnes. Applications include full-scale burst, wide plate, biaxial and pipe bend testing. The facility has inbuilt CCTV for recording and monitoring tests remotely via video and clients receive a copy of their test footage.
Standard testing
Specialist mechanical testing
Standard tests we undertake include Pellini, Charpy, hardness, tensile and bend testing. Our express testing service for standard types of fracture mechanics specimen can provide results as test certificates with a fast turnaround. We also offer training in fracture toughness testing.
Fracture toughness testing is a key input for fitness-forservice assessments, encompassing routine tests that require fast turnaround times through to bespoke, nonstandard fracture mechanics tests. TWI’s knowledge of fracture toughness tests is based on extensive involvement in standards committees, fracture research and the design and build of customised test facilities for ambient and aggressive environments. We interpret complex results, such as fitting tearing resistance curves, and explain low results or tests that do not fully meet qualification criteria including whether the data can safely be used. Our services cover standard and custom fracture and fatigue testing, including high and low-cycle fatigue tests; resonance testing for pipelines; high speed fracture tests; fracture toughness tests at high or low temperatures; and fatigue crack growth tests. Bespoke test rigs can be designed and built at TWI, tailored to clients’ specific mechanical testing needs. We also provide environmental testing of polymers and non-metallic materials, which are increasingly being selected for deployment in harsh locations. This includes developing custom tests, interpreting results and evaluating products.
Fatigue integrity management Fatigue is relevant to all industries because it is the most common mode of failure in structural and mechanical components. If unchecked, it can lead to major breakdown with potentially severe consequences to plant, equipment, the environment and human lives.
Numerical modelling to examine stresses in mooring chain links
TWI’s fatigue specialists draw on more than 50 years’ worth of research and expertise in fatigue analysis, design, assessment and testing. They regularly work with clients in the oil and gas, power, construction and other industries on the monitoring and life extension of components such as girth welds in pipelines and risers, joints in offshore and bridge structures and road and rail vehicle parts.
Numerical modelling and optimisation Numerical modelling, optimisation and, in particular, Finite Element Analysis (FEA) enable innovation, provide cost savings and guarantee reliability via simulation of the behaviour of structures under static, dynamic, thermal and cyclic loads.
Fatigue consultancy Whether you are developing a small component or building a major structure, fatigue assessment at the concept or early design stage can provide you with significant savings. It helps to minimise the risk of design errors, avoids the need for design changes and re-working and can subsequently prevent costly fatigue failures. Our fatigue engineers carry out in-depth analysis and testing of structures. They identify the areas in which fatigue is likely to occur, provide information on the fatigue life improvement of existing structures and advise on current international standards for fatigue design and assessment.
TWI’s Numerical Modelling and Optimisation team provides modelling as an integrated engineering solution for consultancy, long-term R&D and failure investigation, adding great value across the oil and gas, power, construction, transport, electronics and other industries. Comprising engineers, mathematicians, physicists and NAFEMS-certified Professional Simulation Engineers, it offers expertise in a number of areas.
TWI is represented on many standards committees and plays a lead role in the development of industry standards, some of which are BS 7608, BS 7910, Eurocode 3 and IIW guidance documents. We also provide expert witness for litigation cases and arbitration for disputes concerning liability.
Fatigue lifespan prediction In many fatigue assessments, the most difficult and critical step is characterising the in-service loads. Once these are known, further analysis can be carried out to assess the expected fatigue life. Measured strains can be used directly for fatigue lifespan prediction. Alternatively, instrumentation to measure applied forces and displacements in relevant locations on a structure allows for a realistic input into finite element analysis (FEA) models or other methods of analysis, resulting in more accurate predictions of fatigue life.
Fracture and fatigue integrity For structures ranging from fire-damaged pressure vessels to petroleum road fuel tankers, TWI can analyse complex 3D cracks under multi-axial loading conditions to identify the safe operating life and defect tolerance of safetycritical components. The outputs of these simulations support advanced fitness-for-service and engineering critical assessment by providing code-compliant fracture mechanics simulations.
Weld modelling and distortion prediction TWI has an extensive track record in developing and analysing weld models to predict residual stresses, distortion and metallurgical evolutions. These models range from multi-pass girth welds to ship panels comprising hundreds of single pass welds. In conjunction with stateof-the-art optimisation routines, TWI can identify optimal process parameters and weld sequences to minimise distortion and residual stresses, ultimately enhancing the performance and flaw tolerance of fabricated structures.
Material performance in aggressive environments Leveraging multi-scale and multi-physics simulations, TWI simulates damage accumulation and propagation across multiple length-scales, enabling accurate predictions of fatigue crack growth; wear mechanisms; environmental degradation; and progressive failure in composite aerospace parts, subsea equipment in the presence of corrosive fluids and nanostructured coatings.
Modelling support for additive manufacturing Through collaborative R&D programmes, TWI provides modelling support for the development and adoption of additive manufacturing (AM) technology across multiple industry sectors. Projects include topology optimisation; light-weighting and design-for-AM; process simulations for selective laser melting; direct energy deposition and wirefed AM; and the integration of metallic micro-lattices to support the development of novel medical devices.
Simulation of inspection and testing procedures Combining analytical and numerical models with experimental validation, TWI models non-destructive testing procedures such as guided waves and ultrasonic inspection methods to optimise the location of sensors and inspection intervals, leading to improved input for engineering critical assessments.
Ultrasonic inspection of complex geometries in immersion tank
About TWI TWI is one of the world’s foremost independent research and technology organisations, with expertise in solving problems in all aspects of manufacturing, fabrication and whole-life integrity management technologies. Established at Great Abington, Cambridge, UK in 1946 and with facilities across the globe, the company has a first-class reputation for service through its teams of internationally respected consultants, scientists, engineers and support staff. The company employs more than 900 staff, serving 700 Member companies across 4500 sites in 80 countries. TWI also houses a professional institution, The Welding Institute, with a separate membership of over 6000 individuals. TWI offers a single, impartial source of service for joining engineering materials. Technical services range from initial design, materials selection, production and quality assurance, through to service performance and repair.
TWI Ltd, Granta Park, Great Abington, Cambridge CB21 6AL, United Kingdom Tel: +44 (0)1223 899000 Fax: +44 (0)1223 892588 E-mail: twi@twi-global.com Web: www.twi-global.com
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TWI Ltd, Cambridge, UK