Full-time PhD Studentship: Measurement of Residual Stress in Composite Materials

Open University - School of Engineering and Innovation, Faculty of Science, Technology, Engineering and Mathematics (STEM)

The School of Engineering and Innovation invites applications for this three-year full-time PhD studentship starting in October 2017.

Project Description

Composite materials are increasingly being used across different industrial sectors including automotive, aircraft and space applications. However, the structural performance of composites can be influenced by the presence of internal stress. Residual stress is inevitably introduced in manufactured composite parts due to the mismatch of thermal expansion coefficients between matrix and fiber materials when cooling from fabrication to room temperature. These locked-in stresses can lead to plastic deformation, matrix cracking and fibre/matrix interface debonding.

Reliable characterisation of the residual stress state in manufactured composite parts is essential for two reasons. First the information could be used to reduce the uncertainty in failure prediction of safety critical structures and secondly, optimum fabrication routes could be designed which lead to the introduction of beneficial residual stress in high efficiency composite structures.

The aim of the proposed research is develop, apply and validate advanced techniques for quantifying residual stresses in composite materials. An initial focus will be to adapt the contour method, a research area for which the Open University is known internationally. The contour method involves sectioning a body, which contains residual stress, into two halves using a suitable cutting technique, measuring the deformation of the created cut surfaces and using this information to back-calculate the residual stresses that were present in the body prior to performing the cut using Finite Element (FE) stress analysis. However, application of the contour method to composite materials is not trivial for several reasons. For example most composite materials (including carbon fibre reinforced polymers which will be examined in this project) are not electrically conductive and hence cannot be sectioned using wire EDM that is conventionally used for metals. Other challenges will involve understanding and modelling the bulk mechanical behaviour and fibre-matrix interactions. Other stress measurement techniques such as slitting, synchrotron diffraction, neutron diffraction and raman as well as modern material imaging and microstructural characterisation techniques will be applied as required.

Funding Information

This project is supervised by Dr Sanjooram Paddea, Dr Foroogh Hosseinzadeh and Prof John Bouchard. The studentship is fully funded for 3 years, covering tuition fees and provides a stipend of c. £14,533 per year.

Candidates should have (or expect to achieve): a first or upper second class degree in Solid Mechanics or Mechanical Engineering, or in closely related areas, and enthusiasm for laboratory work and innovation. The student will join a well-established team researching residual stress in engineering structures and working within the world leading Contour Measurement Facility at the Open University.

How to Apply

Please visit the following web site for further information on applying to the Open University. Please note, this is a full-time 3-year studentship and you would be required to live in the UK close to the university campus in Milton Keynes. For more information on the application process see:


Enquiries about these studentships may be directed to any of the potential supervisors indicated above.

Please send an email with your CV, a completed application form and a personal statement (outlining your suitability for the studentship, what you hope to achieve from the PhD and your research experience to date) to STEM-EI-RESEARCH@open.ac.uk

Interviews: Week beginning 8 May 2017

Equal Opportunity is University Policy

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