Development of a Novel Finite Element Based Residual Stress Analysis Scheme for Selective Laser Melting Process

• Main Authors: Shih-ChunChen, 陳世春
• Other Authors: Kuo-Shen Chen
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/3d8qf9

碩士 === 國立成功大學 === 機械工程學系 === 107 === Selective laser melting (SLM) has been identified as a promising manufacturing technology for modern additive fabrication. However, the main composition of this process is powder melting during fabrication. Due to enormous thermo-mechanical mismatch, consequently, significant structural distortion and thermal stress would be expected. Current finite element analysis usually needs to pre-assign the material properties and lacks the ability for performing effective material change during simulation. Moreover, the accuracy of the current equivalent SLM FE model still have a lot of room for the improvement. Without correcting these problems, the achieved stress analysis results could be questionable due to uncorrected equivalent process results and the material melting/solidifying effect could not perform well. In this work, the integration of the precise model and the equivalent model would be built to solve these problems. First, for the precise mdoel, the Matlab code would be the main structure with the subroutine FEA, Fortran and Python to create the material melting/solidifying analyzable model, called Model A. Second, for the equivalent model, by simplifying the laser scanning as the thermal strain and using the Model A results to correct the equivalent model results, the efficiently and accurately equivalent model would be built and called Model B. In this approach, it is possible to adequately describe the residual stress and distortion more accurate and efficient in SLM model and it could be applied to other high coupling problems.