Abstract

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.

Abstract

The present work aims to investigate the mechanical properties of the cellular structure based on the Isotruss unit cell by implementing the finite element method (FEM) introducing a representative elementary volume (REV). As an orthotropic cellular structure, the three principal Young's modulus along the longitudinal and transversal directions are evaluated. The influence of the geometrical parameters on the elastic properties is studied in detail. Results reveal that Young's modulus in two transverse directions are almost close, showing a 12% difference. Besides, the proposed unit cell presents the ability to tune the elasticity along with the main directions. It is seen that increasing the angle of helical pitch, increases the longitudinal Young's modulus while decreases the transverse ones that suggest a considerable possibility for optimal designs. As an example, mimicking Young's modulus of the human cortical bone as an orthotropic material is explored and it is seen that the presented cellular structure based on the Isotruss unit cell can successfully fit.