Full process chain simulation of the (wire-based) laser metal deposition process towards fatigue life prediction

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Koenis, T.P.A.
Brink, W.M. van den
Bosman, M.
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Netherlands Aerospace Centre NLR
As virtual manufacturing in additive manufacturing (AM) becomes more mature, the benefits of using this technology increases. Virtual manufacturing simulations often capture only one step in the AM process chain decoupled from the subsequent steps. However, all steps in the process chain influence the final product in their own way. Therefore, this study focusses on the development of a virtual manufacturing framework to perform sequential process simulations of the complete process chain for AM parts. This framework can ultimately be used to obtain insights on the effect of additional processes or process variations on the final product. In this study, the framework is used to obtain insights on the effect of residual stress due to the laser metal deposition (LMD) process on the fatigue life of the final part. To this end, a calibration and validation of a part-scale LMD process simulation is performed to obtain deformations and residual stresses. This is followed by a heat treatment simulation to determine the effect of post heat treatment on the deformation and residual stresses of the final part. As the numerical simulations of the post-processes are purely based on literature and not validated experimentally, the simulations can only be used to qualitatively estimate the residual stresses after post-processing. By combining the residual stress field with externally applied loads, the effect of different process steps on the fatigue life is investigated. To demonstrate this framework, the full virtual process chain of a fictional use case for a simple aerospace bracket is analyzed to observe qualitatively the influence of individual process steps on the fatigue life of the final component.
This report is based on a presentation held at the ESIAM21, Online, 8-10/09/2021.