Open AccessAn efficient numerical model for predicting residual stress and strain in parts manufactured by laser powder bed fusion
Author(s) -
Hui Huang,
Yiyu Wang,
Jian Chen,
Feng Zhao
Publication year - 2021
Publication title -
jphys materials
Language(s) - English
Resource type - Journals
ISSN - 2515-7639
DOI - 10.1088/2515-7639/ac09d5
Subject(s) - residual stress , materials science , finite element method , distortion (music) , inconel 625 , selective laser melting , fusion , inconel , stress (linguistics) , residual , conical surface , thermal conduction , mechanical engineering , mechanics , structural engineering , computer science , composite material , alloy , algorithm , engineering , amplifier , linguistics , microstructure , philosophy , physics , optoelectronics , cmos
Computational modeling of additively manufactured structures plays an increasingly important role in product design and optimization. For laser powder bed fusion processes, the accurate modeling of stress and distortion requires large amount of computational cost due to very localized heat input and evolving complex geometries. The current study takes advantage of a graphics processing unit accelerated explicit finite element analysis code and approximated heat conduction analysis to predict the macroscopic thermo-mechanical behavior in laser selective melting. Adjacent layers and tracks were lumped to reduce the number of time steps and elements in the finite element model. The effects of track and layer grouping on prediction accuracy and solution efficiency are investigated to provide a guidance for a cost-effective simulation. Thin-wall builds from Inconel alloy 625 (IN625) powders were simulated by applying the developed modeling approach to get the detailed residual stress and distortion at a computational speed 50 times higher than conventional approach. Under repeated heating and cooling cycles, a high tensile stress was produced near surfaces of a build due to a larger shrinkage on surface than that in central area. It is also shown that horizontal stresses concentrate near the root and top layers of the IN625 build. The predicted residual elastic strain distribution was validated by the experimental measurement using x-ray synchrotron diffraction.