Computational modelling of thermomechanical behaviour of cast irons: effect of boundary conditions

In this work, a microstructure-based modelling approach is employed to investigate the performance of cast irons under thermal loading. Cast irons have a complex microstructure with graphite particles of different shapes, sizes and orientations embedded in an iron matrix. As a result of the mismatch in coefficients of thermal expansion of constituents, even a purely thermal load can cause failure. To evaluate this behaviour, representative volume elements of cast-iron microstructures are studied using finite-element simulations. Specific inputs in the models are provided based on statistical analysis of SEM micrographs. Further, the influence of boundary conditions is discussed. The obtained results demonstrate that the failure in the examined unit cells is sensitive to the adopted modelling assumptions, as well as the boundary conditions.