Design and optimisation methodologies for Additive Layer Manufacturing (ALM) considering uncertainties

Additive Layer Manufacturing (ALM) is a class of production methods where objects are produced by adding material to the work piece to make 3D objects, on a layer-wise manner. This work is focused on Selective Laser Melting (SLM), an ALM process that is used to manufacture metallic components. This process possesses a significant amount of advantages over conventional manufacturing methods, with the almost unlimited geometrical freedom being one the most important, at the same time this process is affected by some technical challenges, which represent opportunities for research and development. In this work, a design and optimisation methodology that considers several types of uncertainties is outlined, explained and validated. The design and optimisation cycle consists on the use of topology optimisation in order to obtain an optimised baseline geometry and subsequent robust and reliable shape and size optimisation analysis that minimise sensitivity of the component to actual real world operation uncertainties. This methodology considers various types of uncertainties, namely in the loading and boundary conditions, mechanical properties and component's geometry. In order to reduce the gap between the current state of SLM as a manufacturing process and the application of this technology to industrial manufacturing, some of this technology's technical challenges have been addressed. During this work, a detailed mechanical characterisation was performed, considering the inherent sources of variability and also the effect of the surface finish on fatigue properties. As a case study, the developed methodologies are applied to the design and analysis of an aircraft bracket where the ALM method is compared with conventional manufacturing solutions.