Multiphysics modeling and simulation of laser additive manufacturing process

摘要

Additive manufacturing (AM) process is associated with building up parts in layers using 3D printing technology. The term "3D printing" is fundamentally utilized in the literature as a synonym for Additive Manufacturing. Power Bed Fusion (PBF) and Direct Energy Deposition techniques are two popular AM techniques where parts are manufactured layer by layer using a source of energy to fuse successive layers together. Due to non-homogeneous heating and cooling that occur in such AM processes, residual stresses and anisotropic material properties are the most common issues that might affect the quality and reliability of the manufactured objects. Therefore, knowledge of the thermal history of the parts during manufacturing process is significant. In this investigation, a finite element model using commercial software (ANSYS) is developed to model transient heat transfer process in an object during laser additive manufacturing process. The laser is modeled as a moving heat source with a Gaussian energy distribution. The effects of varying the laser scan speed, direction of the laser speed as well as phase change (melting/solidification) on the temperature variations are analyzed in this study. Moreover, temperature dependent thermal properties (such as thermal conductivity, density, and enthalpy) are considered in the model. More complexity was added to the geometry by simulated the building of a half cylinder as compared to straight layers normally used in similar studies. Simulation results were validated against the experimental results found in the literature. A mesh sensitivity analysis was conducted. It is anticipated that the results of this study will help better understand the effect of additive manufacturing process parameters on the quality and properties of manufactured objects.