Extension of the eigenerosion approach to ductile crack propagation at large strains and its application on hard metal microstructures

Abstract

AbstractThe efficient operation of mechanized tunnel drilling machines is strongly determined by the wear resistance of the applied mining tools. Especially in chisels, but also partly in cutting disks, hard metals are used. Their wear mechanism is dominated by surface spalling, i.e. subcritical crack propagation through the material's microstructure mainly consisting of a ductile metal matrix and carbide inclusions. Since this process is mainly governed by the morphology of the microstructure and the mechanical behavior of the individual phases, simulations at the microscale enable the design of improved materials. In this contribution a method for the modeling of this process is presented. The approach is based on the eigenerosion framework introduced in [1] and an algorithmic scheme for large strains is given, which extends the small strain implementation in [2]. For the phases at the microscale the finite strain plasticity formulation [3] is applied. Furthermore, simulations are carried out on the microscale by applying the Finite Cell Method [4] on hard metal microstructures. Here, a specific cell arrangement is constructed which minimizes the required number of cells for a given microstructure morphology. By evaluating the results of these simulations, failure of the material can be investigated on a microscopic level and improvements of the material morphology regarding wear can be realized.