Image Based Finite Element Modelling for the Mechanical Characterisation of Complex Material Systems
Thesis or dissertation
University of Exeter
Reason for embargo
To publish papers using material from the thesis
There is been increasing interest in understanding the physical properties of cellular solid for designing function specific architectures. A new approach has been adopted for modelling those complex micro-systems using image based techniques. The image based meshing is a novel method capable of generating the required volume discretisation (finite element and finite volume meshes) directly and robustly from the image data obtained from a range of imaging modalities such as magnetic resonance imaging and computed tomography. The purpose of the present work is combining image based meshing with finite element method (FEM) for mechanically characterise complex micro-structures. Cellular solid, previously investigated using conventional analytical and experimental approaches and their limitations, will be now explored with the accuracy and the precision of the image based finite element approach. Analytical models of the mechanics of open cell foams are reviewed and extended into a new parametric model which includes axial compression as deformation mechanism during compression. The parametric model, supported by the novel method, is used to predict the mechanical behaviour of two regular open cell micro-structures and a topology obtained from tomographic imaging of an open celled foam. The new approach is then extended to the dynamic analysis of a Polyurethane open cell foam under large strain deformation and different boundary conditions. Bone scaffolds, having the architecture of cellular solids, are mechanically characterised and parametrically investigated. Finally the novel method is applied on two phases composite systems on which a wide range of parametric and sensitivity analysis are carried out. The potentialities of combining image based techniques with FEM are then enlighten. keywords: cellular solid, image processing, Finite Element Method, image based meshing, large strain deformation, dynamic analysis, bone scaffold, synthetic structures, Alumina-Aluminium composite, parametric model, Polyurethane open cell foam, reverse engineering, material characterisation, lattice factory.
PhD in Engineering