TWI Industrial Member Collaborates on Automotive Project

TWI Industrial Member company Gestamp, in the UK is the Lead consortium member on the BRACE project: Breakthrough Reinforcement for Added Chassis Efficiency for Lighter, Safer Vehicles, which won public funding from Innovate UK in 2021 for a two-year duration.

Gestamp designs and develops chassis products for most of the global OEMs. Design follows the mantra of “right material at the right place” and is supported with inhouse developed, leading edge software tools for lightweight chassis parts. Besides the development, the global manufacturing of the chassis parts is key for Gestamp, and underpinned with prototype manufacturing, tool development and testing. As a result, the company has a reputation for being a highly experienced and innovative supplier to the automotive industry. Today, Gestamp continues to innovate in product/process and materials development, and sees hybrid material structures as an important milestone in developing advanced technological parts for application on future OEM platforms.

TWI operates a number of research programmes, one of which focuses on competitively applying to public funding streams from the UK, Europe and wider, to enable the delivery of collaborative projects in the range of Technology Readiness Levels (TRLs) 1-7. Such projects are the responsibility of dedicated consortia, and TWI Industrial Members have the opportunity to participate in these where there is synergy between their own technologies and aspirations, and those of TWI and its Innovation Centres, and the parameters of particular public funding calls.

In support of the collaborative project development and bidding process, TWI, within its Innovation Network (TWIIN), has a dedicated team called Technology Innovation Management (TIM). TIM identifies and brings together SMEs, larger companies and research and technology organisations (RTOs) with TWI’s Technical sections, Innovation Centres and Member companies, into specific consortia, and supports them through the concept development, proposal writing and submission stages.

When a consortium has created and submitted its proposal, also known as a bid document, and goes on to be successful in winning public funding, the collaborative project is then able to go ahead.

TIM has a demonstrable track record in this area and, since 2008, has assisted more than 1,100 partners in the UK and internationally to secure over 400 projects, backed by circa £579m of public funding (figures correct as of April 2022).

Objective

To add value to TWI Member companies’ research and development (R&D) activities, thereby contributing to their market positioning, by selecting, and including them in, suitable project proposals to bid for public funding.

Approach

The BRACE project journey began when the Brunel Composites Centre (BCC), an Innovation Centre established as a joint venture between TWI and Brunel University London in 2016, first identified the need for deploying a novel joining method for dissimilar materials that combines practicality, performance and the opportunity to disassemble at a product’s end-of-life. With the support of TWI’s Advanced Composites and Adhesives (ACA) section, the joining method selected was the Polymer Coating Material (PCM) technique.

PCM involves the use of thermoplastics as structural adhesives where the final assembly operation is a polymer weld. In the manufacture of a joint between a thermoplastic component and a dissimilar material component, for example metal), the non-thermoplastic component is first coated with the same thermoplastic before both components are welded together.

Next BCC proposed the Innovate UK funding route to the TIM team, who assisted with inviting potential project partners, including Gestamp, to join the consortium. The project was named “BRACE” and is the responsibility of partners Gestamp UK, FAR-UK Ltd, Gestamp Spain, TWI and Brunel Composites Centre. TIM also contributed their expertise to help shape the project idea and turn it into a proposal for public funding, working closely with the consortium members.

The BRACE proposal was successful in securing the desired funding from Innovate UK, following which the the consortium members were able to commence the project.

Solutions

Each consortium partner is contributing to the project as follows:

Gestamp UK’s Advanced Technology Team are the technical lead for BRACE, and is responsible for the technology feasibility study, and the design and development of the parts it requires
Gestamp Spain are developing the feasibility lab-prototypes, and testing, evaluating and validating the proposed dissimilar materials joining system
TWI invented the PCM technique and is responsible for conceiving the overall system for BRACE
FAR-UK Ltd is contributing through preparing and characterising the test coupons
Brunel Composites Centre is carrying out the finite element modelling and optimisation of the proposed system.

The target application for the technology is automotive chassis and body-in-white parts assembly. A schematic illustration for the PCM joint and carbon/PEEK stiffener to aluminium joint demonstrations can be seen in Figures 1 and 2 respectively (below right).

Three standard components manufactured by Gestamp Chassis, in the form of painted and unpainted, aluminium and steel lower control arms, were selected for the feasibility study (see Figure 3 - below right). The aim is to apply thermoplastic composite patches, using the PCM joining method, to these parts to increase their stiffness, improve noise, vibration and harshness levels for higher-end models, and explore the possibility of downgauging standard parts where economically viable weight reduction is possible.

A preliminary component scale analysis was created by Gestamp to assess the buckling behaviour of the chosen demonstration parts, with and without the thermoplastic patches. Based on assumed joint parameters, the buckling force needed for both the steel and aluminium was increased by 13.5% and 13.9% after using the thermoplastic patch, respectively (see Figure 4 - below right).

Benefits and Conclusion

By achieving the project’s objectives, BRACE will contribute a number of improvements beyond existing, state-of-the-art solutions for the joining of dissimilar materials. Compared to using mechanical fastening as a means of joining, when using the new method, no stress concentrations are introduced to joint parts and materials do not need to be drilled. These negate the risk of water damage, up gauging thickness, and strength reduction due to fibre damage and delamination. In addition, in comparison to using adhesives, epoxy and intensive surface preparation are not required, hence the solution is not subject to curing times or restricted in its shelf life, meaning it offers a clean disassembly opportunity.

The technology conceived within BRACE also has the potential to be developed further for deployment in a range of other sectors including wind energy, marine, sports and leisure.

On completion, BRACE will deliver an innovative new process and delivery system for the joining of advanced thermoplastic composites to metals assembly, initially for use in the automotive sector but with the potential to be developed further, for application in a range of other sectors such as wind energy, marine, and sports and leisure.

TWI was delighted to assist Gestamp Chassis UK in joining the BRACE project consortium and contributing to the winning bid, and is looking forward to working with them on more new technology concepts in the future.

BRACE has secured funding from Innovate UK under EUREKA collaborative R&D programme 107471.

Figure 1. Schematic cross-section through a PCM joint.

Figure 2. TWI Ltd PCM joining demonstration of dissimilar materials: a) carbon/PEEK stiffener joined to the PCM aluminium alloy panel, b) PCM aluminium alloy stiffener joined to carbon/PEEK panel (copyright TWI).

Figure 3. The proposed metallic chassis components by Gestamp that will be strengthened with thermoplastic composite patches using the PCM joining method.

Figure 4. Preliminary simulations by Gestamp show an increase in buckling strength of the LCA after using a thermoplastic patch.

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