| Résumé | Additive manufacturing (AM) technology cuts across a large number of industries and applications, and that is part of what makes its potential so compelling. Aerospace, automotive and medical products will drive AM into the future. Laser Powder Bed Fusion (LPBF) is a powder-bed fusion AM process that can be effectively utilized to manufacture structural components with complex geometries. In LPBF, a part is created directly from the three-dimensional model by selectively melting successive powder layers using a laser beam. Nevertheless, there are still some technical barriers and challenges for the production of metallic parts. Optimal production of metallic parts using LPBF requires a comprehensive understanding of the effect of main processing parameters such as laser energy input, powder bed properties and builds conditions. One of the main issues is the identification of ideal process parameters to build a component with minimal induced residual and thermal stresses which are the main cause of distortion. Development of a numerical model to accurately predict the induced residual stresses and distortion during the LPBF process would be of great interest as it would allow to effectively investigate the influence of processing parameters on the quality of the parts. Additionally, a reliable numerical model can drastically reduce the expensive experimental costs associated with the number of tests, cut-ups, as well as manufacturing iterations required for the development of additive manufactured parts. In this study, a high fidelity finite element (FE) model has been developed to numerically simulate the LPBF process in order to predict the induced residual stresses and distortions. A novel multiscale modelling approach has been developed for three dimensional (3D) layer-by-layer simulation of LPBF. First, a microscale FE model has been introduced to predict the melt pool size and temperature profiles. Subsequently, a 3D thermo-mechanical macroscale model has been developed to determine the induced residual stresses and distortions. An extensive experimental investigation has also been conducted to support and validate the developed FE models. |
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