Start date and planned duration: April 2018, 36 months
- Develop two novel processes, embedded fibres and laser riveting, to fabricate joints between metals and carbon fibre composites.
- Achieve consistent joint strength greater than 30MPa.
- Create a uniform transition zone between metal and composite, assessed using the strain distribution measured by DIC.
- Develop the business case for implementation.
Optimisation of high-performance engineering structures continues to place greater emphasis on multi-materials solutions – using the right material in the right place. Composites offer high specific strength and stiffness, corrosion and fatigue resistance, whereas metals provide solutions for temperature resistance, energy absorption, high bearing load resistance and (typically) lower cost. Automotive and aerospace companies are increasingly looking to use composites to achieve up to 50% weight savings over metals. Most applications will inevitably comprise both composites and metals. Currently, mechanical fastenings and adhesive bonding are the predominant methods used for joining composites to metals. These can suffer from several drawbacks: stress concentrations at holes, poor long-term environmental resistance, reduction in strength through cut fibres, limited availability of inspection techniques, non-uniform stress distribution and low production rates. These drawbacks limit the adoption of more advanced multi-material joining applications and reduce potential benefits of optimised designs.
There is therefore considerable interest in innovative joining methods to increase productivity, joint strength and flexibility, and in new approaches to creating structurally efficient transition joints allowing fibres to cross the composite/metal interface. This project will investigate two concepts for novel joints: embedded carbon fibre transition joints, and high productivity laser riveting. Each process will be developed with the aim of preparing consistent joints with strength relevant for industrial applications. The introduction of a transition zone will be demonstrated using DIC, and a techno-economic assessment will be carried out to estimate the cost of implementation.
Benefits to Industry
End users will benefit from improved performance and lightweighting driven by the design flexibility enabled by the new processes. Greater use of composite materials in multi-materials applications will benefit the composites supply chain.
Technical Literature Review: Hybrid Composite-to-Metal Joining, Worrall and Mortello
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