Cradle-to-Grave Life Cycle Prediction of Automotive Materials and Systems in Service: Impact of Ageing on Performance

Lead Research Organisation: University of Manchester
Department Name: Materials

Abstract

Material ageing is commonly understood as changes of material properties with time. This physical or chemical alteration has a detrimental effect on the material properties and leads to gradual loss of the design function and unacceptable loss of efficiency or ultimate failure (in some cases ageing may be observed as an improvement, for instance, engine performance). Ageing of a material system under normal service conditions is a difficult case to treat. Many factors can significantly affect its durability, such as temperature, irradiation, moisture, chemicals, mechanical creep and fatigue loading. Synergism in the global ageing often occurs when the simultaneous action of several stresses results in an ageing effect that differs from that which would be observed if the individual stresses were applied sequentially. In an effort to understand the ageing process, the first task is to identify the age parameter that represents, on a macroscopic scale, the micro and sub microscopic features, underlying processes such as nucleation and growth of micro defects, and/or physico-chemical transformations. The second task consists of formulation of a constitutive equation that can mathematically represent ageing. The third task obviously is the experimental examination of the condition that leads to catastrophes such as small perturbation in controlling parameters leading to large variations of the age parameter. A material tensor "g" can be introduced as an age parameter similar to stresses and temperature. A variational principle approach can then be followed to formulate a constitutive equation for ageing. Interestingly, an evolution of "g" in four dimensional material space-time continuum would lead to an inelastic behaviour, which manifests as time dependent material properties recorded by an external observer. For one of the simplest linearized case this approach leads to a semi-empirical creep behaviour model. Currently, most of the studies are based on accelerated ageing test at coupon level and require extrapolation to normal service conditions of the part/component, resulting in many uncertainties, leading to frequent diagnostic tests in the field (visual inspection, chemical measurements, physical measurements), impacting dramatically on cost. The aim of the proposed work is to develop an 'age-aware' comprehensive simulation tool for the prediction and assessment of critically important automotive components and systems during manufacturing, in-service and the end of life.

Planned Impact

The emphasis of this research theme is to create, a prediction capability for in-service performance throughout the lifetime of the product. This will ensure that the downstream customer experience can maintain JLR's core brand values and customer experiences. Direct beneficiaries of the outcome from the proposed work are Jaguar Land Rover and their affiliates, where the computer simulation tools are used for improving the design and built of components and vehicles, as well as aerospace, marine and other related industries, where many of the concepts and tools developed will be transferable. The acquired knowledge will lead JLR to the improvement of their simulation innovation capability in relation to ageing that would boost robust design, reducing the dependence on physical prototypes during the product development process and leading to reduction in vehicle emissions through increased design optimisation and robustness of virtual design, verification and validation. The results can be used to establish more realistic and consistent quality assessment and performance criteria and increase cost-effectiveness and endurance (durability) in addition to improving the customer driving experience. More broadly, the concept of optimising product/system design for the duration of product/system life using accurate simulation validated by thorough life performance data offers the opportunity to enhance the performance of products and systems in a wide range of industries from aerospace to healthcare with potential for profound long term benefits. Such benefits could go beyond transportation and include improved long term performance of medical diagnostic instruments such as MRI scanners or life support systems such as ventilators and dialysis machines. The results of the project will be advertised to the widest possible scientific and industrial audience at technical workshops, exhibitions, conferences and meetings with industry and academia such as the annual EPSRC Manufacturing The Future Conference and the annual Advanced Engineering Show at NEC Birmingham (after consultation with our JLR sponsors). At the end of the project, developed predictive tools could be transferred fully to any UK company willing to use them in practical design, e.g. within finite element packages used in analysis of structural components. The proposed project will improve the general understanding of ageing behaviour of metallic and non-metallic materials. The acquired knowledge will help researchers in academia and industry who investigate the dynamic response of advanced materials and structures operating in demanding environments to solve further issues relating to improvement of design and reduction of fabrication and manufacturing costs. The main research results will be published in refereed international journals and presented at international conferences. Web documents will also be placed on the Universities web portal, giving descriptions of the work that can be understood by interested members of the public, including prospective students. The Web presentation format is an extremely efficient way to disseminate scientific information. JLR will be consulted to ensure that any intellectual property rights are properly safeguarded. Direct communication with researchers in the field and attendance at conferences will also be important for the dissemination of results. Terms of engagement will be based on a Collaboration Agreement to be established between JLR, UoM and UoS. This will include non-disclosure of information, intellectual property rights and protocols for exploiting the results of the project. In particular, conditions for publication of results can be delayed at the request of JLR, but not indefinitely. A maximum 12 month delay is suggested. PhD theses of linked PhD projects would also not be included in this type of embargo arrangement.

Publications

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Soltani P (2016) Nonlinear Dynamics of Structures with Material Degradation in Journal of Physics: Conference Series

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Wang Y (2019) Modelling corrosion effect on stiffness of automotive suspension springs in Material Design & Processing Communications

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Yar M (2018) Corrosion behaviour of an industrial shot-peened and coated automotive spring steel AISI 9254 in Corrosion Engineering, Science and Technology

 
Description Theme 9 of the SimuLife project was designed to develop an 'age-aware' comprehensive simulation tool for prediction and assessment of critically important automotive components and systems during manufacturing, in-service/end of life.
Key findings: simulation capabilities in the areas of:
- the corrosion evolution of suspension springs over time that can affect vehicle ride comfort, noise, vibration and harshness (NVH) in addition to handling;
- the extent and mechanisms of change in properties of sulphur cured rubber in engine mounts and resultant change in ride comfort and NVH;
- the mechanisms of change in properties of the areas surrounding heating, ventilation and air conditioning (HVAC) vents in an instrument pack, and the resulting change in NVH.
- Life Cycle Assessment (LCA) that involves a cost/performance and environmental impact assessment integrating the manufacturing, operational, and the end-of life stages using specialised software packages (SCEnAT+ and GaBi), capable of inventory data modification and analysis.

The work provides methodologies (numerical techniques) which can be applied to other material systems while the physics in each model is material dependent. Coupon data and observations inform/validate material models which are then implemented in ABAQUS, a commercially available finite element software for prediction of aged component behaviour over service life taking into account the dynamic loading on the specific component. A survey was also designed and conducted to improve our understanding on how automotive customers perceive ride and handling problems with their cars ageing (perception on the vibration, noise, and harshness), and also to see what motivates them and influences their decision to purchase (e.g. cost of ownership, fuel efficiency)
The research findings and methodologies were presented in detailed technical reports, workshops, national and international conferences and published in peer reviewed journals.
Exploitation Route The work provides methodologies (numerical techniques) which can be applied to other material systems while the physics in each model is material dependent. Coupon data and observations inform/validate material models which can then be implemented in ABAQUS, or any other commercially available finite element software for prediction of aged component behaviour over service life taking into account the dynamic loading on the specific component. SCEnAT suites (cloud based software) can be used to assess the life cycle environmental impact of components and compare life cycle environmental impact of a new design (with new light-weight materials) against existing materials
Sectors Aerospace, Defence and Marine,Manufacturing, including Industrial Biotechology,Transport

 
Title Life Cycle Environmental Impact Software: SCEnAT suites 
Description SCEnAT suites (cloud based software developed by co-investigator Prof Lenny Koh in partnership with Microsoft) have been used by JLR in assessing the life cycle environmental impact of several components for two specific vehicles models. SCEnAT suites have also been used by JLR in comparing life cycle environmental impact of new design (with new light-weight materials) against existing materials. The impact of these research have also been captured in a video and a letter. 
Type Of Technology Software 
Year Produced 2018 
Impact Used by JLR in assessing the life cycle environmental impact of several components for two specific vehicle models 
URL https://www.sheffield.ac.uk/are