Date of Award
Master of Science in Engineering
Mechanical and Aerospace Engineering
Dr. Peter A. Gustafson
Dr. Pnina Ari-Gur
Dr. Jinseok Kim
Dr. Evan J. Pineda
Metal additive manufacturing, residual stress, thermomechanical simulation, inherent strain method
Masters Thesis-Open Access
Metal additive manufacturing is an enabling technology for the rapid prototyping and manufacturing of geometrically complex parts that would otherwise be difficult or impossible to manufacture. However, the manufacturing process can produce undesired residual stresses and distortions. The first part of the work describes the implementation of a multiscale, thermo-mechanical simulation modeling the metal powder bed fusion additive manufacturing process. NASA’s Micromechanics Analysis Code was is to incorporate the microscale effects of an evolving material porosity on the predicted macroscale residual fields. The simulation shows that modeling an evolving material porosity, as the material transitions from a metal powder to a solid, significantly affects the magnitude of the residual stresses and distortions, compared to a constant porosity model. The second part of this work uses the developed simulations to assess the effects of geometrical features. A linear regression shows that there is a correlation between the residual fields and the geometry. This suggests that it may be feasible to predictably influence the residual fields by modifying the geometry. This work is part of a larger work aimed at optimizing the geometry to minimize the residual stresses and distortions.
Silva Velasco, Luis Fernando, "A Multiscale Thermomechanical Metal Additive Manufacturing Simulation and the Impact of Geometry on Residual Stress and Distortion" (2020). Master's Theses. 5166.