Computer modelling of damage in high strength steel




The construction industry these days, adopt novel materials such as high strength steel, which are products of new manufacturing techniques and processes. These processes alter the steel’s microstructure such as its grain size and grain distribution; and chemical composition. The different phases in the microstructure, as a result of these manufacturing techniques, play a huge role in determining the final material characteristics of steel such as the yield and ultimate strength and energy absorption. To optimise the design of steel, numerical modelling is usually employed to simulate the material response, which is generally nonlinear due to the nucleation of micro-cracks, coalescence and propagation of macro-cracks within the material. There is a knowledge gap in modelling such types of processes using current numerical methods due to the difficulty in handling the nonlinear response and the changes in the mesh as the fractures evolve. A robust technique for modelling ductile fracture in steel will be established within the polytope-framework of the scaled boundary finite element method originally developed by Ooi et al (2012). A concise mathematical formulation will be developed to enable the SBFEM to model large strain-large displacement material responses associated with metals experiencing large plastic deformation. Parametric studies will then be undertaken to investigate numerically, the influence of the steel’s microstructure on the fracture characteristics of metals. It is expected that the developed technique will tackle the difficulties in the numerical modelling of ductile fracture (e.g. evolving mesh topology and excessive element distortion) experienced by mainstream numerical methods e.g. the finite element method, boundary element method and meshless methods. It will also provide future engineers with a virtual tool to investigate the influence of metal microstructure on its fracture characteristics. The outcomes of the project will enhance the capability of analysing ductile fracture in novel materials.


Ooi ET, Song C, Tin-Loi F, Yang Z (2012) Polygon scaled boundary finite elements for crack propagation modelling. Int. J. Numer. Meth. Engng, 91, 319-342


Principal Supervisor: Ooi Ean Tat

Fatemeh Javidan

Hossein Fallahi