In situ analysis of crack fields

Cracks cause the failure of structures that range from nuclear reactors to semi-conductor devices. They are three-dimensional and multi-scale, and propagate by mechanisms that are at the limits of materials performance. Structural engineers need to predict whether and how quickly a crack will propagate with confidence and without excessive conservatism. Materials engineers need to understand how the microstructure can be changed to improve fracture behaviour. As Materials scientists, we investigate the local conditions that exist at the crack tip, which allow it to propagate.

Our approach to this fundamental problem is to simultaneously map the strain and stress fields that surround the crack tip. This can be done at multiple length scales using advanced materials characterisation methods.  Some recent examples include nuclear graphite (http://dx.doi.org/10.1016/j.carbon.2020.09.072), fatigue cracks in metals (http://dx.doi.org/10.1016/j.ijfatigue.2023.107541, http://dx.doi.org/10.1016/j.prostr.2022.03.139) and cleavage cracks in ceramics (http://dx.doi.org/10.1016/j.jmps.2022.105173).

Several projects are available in this area, with the objective of developing novel methods to understand the interaction between processes at the crack tip and the surrounding deformation fields. Cracking mechanisms include  brittle fracture, stress corrosion, fatigue and creep in metals, ceramics, polymers and their composites. The research couples experimental techniques that include X-ray tomography, X-ray diffraction, electron and optical microscopy and Raman spectroscopy with numerical methods that include inverse modelling and finite element methods.  The projects are suitable for graduates with an engineering, mathematical or physical sciences background.