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Advances in Aircraft and Spacecraft Science
  Volume 8, Number 1, January 2021, pages 31-51
DOI: https://doi.org/10.12989/aas.2021.8.1.031
 
open access

Temperature thread multiscale finite element simulation of selective laser melting for the evaluation of process
Kang-Hyun Lee and Gun Jin Yun

 
Abstract
    Selective laser melting (SLM), one of the most widely used powder bed fusion (PBF) additive manufacturing (AM) technology, enables the fabrication of customized metallic parts with complex geometry by layer-by-layer fashion. However, SLM inherently poses several problems such as the discontinuities in the molten track and the steep temperature gradient resulting in a high degree of residual stress. To avoid such defects, this study proposes a temperature thread multiscale model of SLM for the evaluation of the process at different scales. In microscale melt pool analysis, the laser beam parameters were evaluated based on the predicted melt pool morphology to check for lack-of-fusion or keyhole defects. The analysis results at microscale were then used to build an equivalent body heat flux model to obtain the residual stress distribution and the part distortions at the macroscale (part level). To identify the source of uneven heat dissipation, a liquid lifetime contour at macroscale was investigated. The predicted distortion was also experimentally validated showing a good agreement with the experimental measurement.
 
Key Words
    selective laser melting; melt pool morphology; distortion; residual stress; finite element analysis; Ti-6Al-4V
 
Address
Kang-Hyun Lee: Department of Mechanical & Aerospace Engineering, Seoul National University, Gwanak-gu Gwanak-ro 1 Seoul 08826, Republic of Korea

Gun Jin Yun: Institute of Advanced Aerospace Technology, Seoul National University, Gwanak-gu Gwanak-ro 1, Seoul 08826, Republic of Korea
 

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