Embedded Carbon Fibre Transition Zones for Metal-Composite Hybrid Joints

Background

Driven by European Regulations (No. 443/2009) and the USA Corporate Average Fuel Economy (CAFE) standard, automotive and aerospace companies are increasingly looking to use carbon fibre composites to achieve up to 50% weight savings over metallic alternatives. However, it is unlikely that these industries will adopt a 100% composite solution, and the optimum design will inevitably comprise both composites and metals.

Currently, mechanical fastenings and adhesive bonding are the predominant methods used for joining composites to metals. These joining methods can suffer from several drawbacks. Consequently, there is a clear need for new, flexible, cost-effective and rapid methods for joining composites to metals. Therefore TWI is looking into developing the ideal joint between a composite and a metal which efficiently transfers loads from the composite to the metal through the fibres. The joint will have all the advantages of both composite and metal, without adding significant weight.



Project Outline

A fundamental problem with composite/metal joining is that thermal joining of metallic elements generally requires temperatures above the degradation temperature of the composite’s polymer constituents. This high temperature may last only for a very short period.

The PhD is focused on establishing the underpinning fundamental science of high temperature/short time thermal degradation of fibres and composites. The temperature the fibre/composite is reaching during the process is to be measured throughout the process and the material properties to be assessed after the process. This information will be used to develop a high temperature-low duration thermal degradation model.

The PhD research will also focus on fundamental science of the fibre/metal interface, especially after undergoing a severe thermal cycle where the fibre coating may have been damaged. The research will concentrate on characterising the interface and evaluating the effect of different processing conditions on the fibre/matrix adhesion strength.

The proposed research will focus on the following activities to create a smooth transition zone between dissimilar materials.



- Determine the thermal limits of fibres/composites in hybrid joining applications;

- Develop thermal degradation assessment methodology for high-temperature short duration processing;

- Develop a thermal degradation model for high-temperature short duration processing;

- Develop a metal-fibre interface assessment methodology;

- Develop a stress transition model for transition zone hybrid joints.

About NSIRC

NSIRC is a state-of-the-art postgraduate engineering facility established and managed by structural integrity specialist TWI, working closely with lead academic partner Brunel University, top UK and International Universities and a number of leading industrial partners. NSIRC aims to deliver cutting edge research and highly qualified personnel to its key industrial partners.

About Brunel

Brunel University’s Department of Mechanical, Aerospace and Civil Engineering (MACE) is one of the leading engineering departments in the UK, and with over 1250 students, as well as 150 academic staff, it is also one of the largest. Mechanical, Aerospace and Civil Engineering is the combination of Brunel University’s most established subjects, Mechanical Engineering, with both Aerospace and Civil Engineering. The Structural Fire Engineering Research Group comprises of four academic staff and about 10 postdoctoral researchers and PhD students. The group conducts pioneering research on the buildings’ behaviour under fire and explosion.

Candidate Requirements

Candidates should have a relevant degree at 2.1 minimum, or an equivalent overseas degree in ACADEMIC REQUIREMENTS Candidates with suitable work experience and strong capacity in numerical modelling and experimental skills are particularly welcome to apply. Overseas applicants should also submit IELTS results (minimum 6.5) if applicable.