Design and Assessment of Carbon Fibre Composite Joints PhD

Carbon fibre reinforced polymer (CFRP)has high specific strength and stiffness that originates from the continuous reinforcing carbon fibres.

Standard joining technologies include mechanical joints [bolts and rivets] which produce a reliable joint that can be disassembled. However, the mechanical interference requires the reinforcing fibres to be ‘cut’ and compromises the performance of the joint. Currently a design solution is to increase the thickness (and therefore the weight) of CFRP at joints.

The adhesive joint can be a better option when a good joint can be manufactured reliably. However adhesive joint strength can be variable due to surface preparation, contaminants, moisture, degree of cure and other variations during manufacture. This variability can be mitigated to some extent by strict controls to the manufacturing procedure and environment, joint design, inclusion of some surface modification and control of the adhesive cure cycle.

The primary aim of this project is to assess the performance of a variety of CFRP joints, which will include CFRP/Aluminium alloy and/or CFRP/Steel and/or CFRP/Titanium alloy joints in addition to CFRP/CFRP joints and identify design and/or manufacturing procedures that provide improved, damage tolerant joint behaviour. The project objectives will be discussed and formulated within the first 4 months and should include;

• Identify current alternatives to bolted CFRP joints.
• Investigate joint design options, surface preparation techniques and adhesives for CFRP/CFRP and CFRP/metal joints.
• Design test protocols for measuring the performance of candidate joints and determine failure mechanisms.
• Build and test candidate joints and measure performance.
• Recommend procedures for manufacture of adhesive joints.

There might also be opportunities to investigate demountable adhesive joints [Bibi et al (2023), Materials today communications, 106293]

There will be opportunities to engage with industries and focus groups that are engaged in adhesive joints e.g. TWI, NCC, BAE Systems. In addition you will be encouraged to attend conferences and workshops associated manufacturing of Composites Structures.