Ajit Achuthan, Associate Professor, Clarkson University
This presentation will discuss the development of a new multi-scale Finite Element (FE) framework to determine the residual stress evolution during the Selective Laser Melting (SLM) process. The framework consists of a macro-scale FE model which calculates the residual stress field for a given residual plastic strain field and thermal shrinking in the printed part. Residual plastic strain field and thermal shrinking is determined by simulating the printing of representative volume elements (RVE) using a micro-scale model. The RVEs correspond to various regions of printed part in terms of equivalent thermal and mechanical boundary conditions. The micro-scale model, which determines the residual plastic strain field, consists of two separate models; a heat transfer analysis model and a structural analysis model. Heat transfer analysis model determines the thermal history by simulating the SLM of the RVE. The structural analysis model then determines the average residual plastic strain for the determined thermal history. Various strategies implemented to enhance computational speed, such as element birth and death hybrid approach, and multiple-model mapping to control the mesh density real time, will be discussed. The application of the framework will be demonstrated by simulating the SLM of a real size part.