The fatigue and fracture properties of engineering materials are measured using standard test specimens; real cracks and engineering components are three-dimensional and more complex, and predicting crack propagation with confidence and without excessive conservatism remains difficult as we typically only know the applied boundary conditions of loads and crack geometry. In this project, we aim for a unified approach to crack propagation by investigating how the applied loading is mediated by the processes that occur around the crack, to determine the actual conditions at the crack tip that allow it to propagate.
One way to address this is to simultaneously examine both the strain and stress fields that cause crack propagation. This can be done by 2D and 3D digital correlation image analysis to obtain precise, in-situ, measurements of the material displacements at the surface and inside solid samples, and also scattering measurements of the deformations of the crystal lattice. (see, for example, https://www.icfweb.org/Procf/ICF14/Vol2/128/, https://dx.doi.org/10.1016/j.carbon.2017.08.075, https://dx.doi.org/10.1007/s11340-017-0275-1 and https://doi.org/10.1016/j.ijfatigue.2020.105474)
The aim of this project is thus to investigate, by experimental techniques that include SEM, XRD (synchrotron), Raman, optical and X-ray tomography and finite element modelling, the propagation of cracks (brittle fracture, stress corrosion and fatigue) with the objective of developing novel methods to better characterise and understand the interaction between events at the crack tip and the surrounding deformation fields. The project is suitable for graduates with an engineering, mathematical or physics background.
The project is suitable for graduates with an engineering, mathematical or physics background.