Thermoelastic Modelling of Additive Manufacturing by Selective Laser Melting

• Autor(a) principal: Ribeiro, Mariana dos Santos
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.6/13033
• topic: Comsol Multiphysics; Fabrico Aditivo de Metais; Livelink for Matlab; Parâmetros de Processamento; Tensões Residuais; Transformações de Fase; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica

Additive manufacturing represents a powerful tool for the production of lightweight and optimised aerospace components capable of enabling an overall mass reduction of the system they are embedded in and, consequently, minimising fuel consumption and pollutant emissions. In particular, combining additive methods with titanium alloys is an attractive solution for saving weight while ensuring structural integrity due to their outstanding specific mechanical properties. The problems associated with the manufacturing of titanium by traditional processes, namely the waste of raw material in relation to the material actually utilised, can be solved by the adoption of additive methods, in particular Selective Laser Melting. Active Space Technologies has been investigating additive­titanium solutions in the scope of the ADVANSS project whose aim was the research, development and manufacturing of a support structure, the Large Lens Mounting. However, the considerable heat exchanges between the substrate, the powder bed, the melt pool and the surrounding environment involved in the process are responsible for inducing large stress concentrations that may cause part failure. The main objective of this work is the development of a thermoelastic model capable of replicating the phenomena occurring during Selective Laser Melting, including material melting and subsequent cooling, with good flexibility in parameter variation. By predicting thermal stresses induced during manufacturing, it is possible to establish a set of process parameters capable of mitigating part imperfections. A series of complementary goals have been proposed as well: carrying out parametric studies to predict stresses induced by a specific set of parameters for a single layer, and later of a whole component, with n layers; building a hierarchy of parameters according to their ability to minimise stresses; and enriching Active Space Technologies expertise in additive manufacturing technologies. The prospect is that the knowledge acquired with this project contributes to the development of a similar model that would optimise the fabrication process of the Large Lens Mounting.