An Integrated Approach for Virtual Microstructure Generation and Micro-Mechanics Modelling for Micro-Forming Simulation

To aid FE simulation for forming micro-components, an integrated approach is proposed to generate virtual microstructure for micro-mechanics modelling. Based on Voronoi tessellation and the probability theory, a VGRAIN system is created for the generation of grains and grain boundaries for micro-materials. The input data of the system are physical parameters of a material, including average, minimum and maximum grain sizes. Numerical procedures have been established to link the physical parameters of a material to the control variable in a gamma distribution equation and a method has been developed to solve the probability equation. These are the basis for the development of the VGRAIN system, which can be used to generate different grain structures and shapes that follow a certain pattern according to the probability theory. Statistical analyses have been carried out to investigate the distribution of generated virtual grains. The generated virtual microstructure is then implemented in the commercial FE code, ABAQUS, for mesh generation and micro-mechanics analysis using crystal plasticity equations for FCC materials. The crystal plasticity model is implemented in the commercial FE code, ABAQUS, through the used-defined subroutine, UMAT. FE analyses have been carried out to investigate size effects and localised necking encountered in micro-forming processes.