Multi-scale Topology Optimisation with Overheating Control for Laser Powder Bed Fusion

In this study, a novel multi-scale approach for TO with overheating control based on the homogenisation of the body-centred cubic (BCC) lattice cell is presented. This allows the intermediate densities to be interpreted with lattice structures with varying relative densities. Homogenised modulus of elasticity and thermal conductivity are used as material interpolation in the density-based TO. Furthermore, the homogenised properties are complemented by the Heaviside function to include manufacturing limits in the form of minimum and maximum relative density. Both fabrication limits namely the minimum feature size and powder accessibility for cleaning are experimentally determined for Ti6Al4V alloy and the BCC lattice unit cell size of 5 mm.