A Statistical Method for Predicting the Compressive Strength of Geometrically-Imperfect Metal Microlattices Produced by Selective Laser Melting

Selective laser melting (SLM) enables the use of metal microlattices in structural parts to reduce weight, improve damage tolerance and allow for increased energy dissipation under impact. However, the extreme processing conditions experienced during production, coupled with machine-to-machine and powder quality variations, mean that analytical predictions and numerical simulations of strength and stiffness based on the theoretical geometry can be unreliable. In this work, a statistical approach is used within a finite element framework to analyse the effect of random variations to the strut geometry, stiffness changes due to porosity, and global imperfections. Monte-Carlo methods are used to produce distributions of the anticipated compression test curves, and the results of these numerical analyses are compared with a series of experimental tests. The comparison shows that the proposed approach enables an improved estimate of the strength distribution of metal microlattices.