Simulation of Crack Propagation for Additive Manufactured Components

Abstract

Additive manufacturing processes are anticipated to greatly contribute toward an industry revelation. Nevertheless, some of these processes have some limitations that prevent them from leading the industrial world, such as the high residual stress in the wire arc additive manufacturing (WAAM) process. One of the main drawbacks of residual stress is its impact on fatigue crack propagation. This impact has been investigated experimentally by several researchers, but only few have investigated it numerically, especially for WAAM. This research connects different software to present a tool that can investigate the residual stress impact on fatigue crack propagation numerically for a WAAM process. The main software are SYSWELD for residual stress prediction, SimModeler for the re-meshing process of the propagation process, and in-house software Frac3D for stress intensity factor (SIF) calculation. The connection process requires several modifications to the software input and output, especially for Frac3D. The modifications focus on data handling between the software and a different Finite element analysis (FEA) approach for the software. This study takes two materials, Austenitic Stainless Steel 316L and titanium alloy Ti-6AL-4V, as examples for the case testing of the standard fatigue crack propagation models E647 and E1820. This research shows computed residual stresses fields for a WAAM printed plate. It presents the impact of the residual stresses in the computation process for fatigue crack propagation using the Paris law for the experimental data from various publications. In addition, limited results are presented using modified crack growth rate laws that take into account the R-ratio