基于热弹塑性本构模型的LPBF全尺寸热-力耦合数值模拟研究

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Abstract： Laser powder bed fusion （LPBF） is an important branch of metal additive manufacturing technology， offering advantages such as personalization and automation.However，residual stress accumulates continuously during the layer-by-layer manufacturing processwhich can easily lead to deformation，fracture，fatigue and other problems，limiting its further application.To predict the displacementand residual stress in metal aditive manufacturing parts，this paper uses the open-source finite element solver code JAX-FEMto conduct Numerical simulation of ful-scale thermal-mechanical coupling for LPBF based on thermal elastic-plastic constitutive model. Equivalent laser power，equivalent laser radius，and scanning speed are determined based on the energy conservation principle，simplifying the computational model and reducing calculation time.By modifying the stresstate of the botom surface of the part，the processofcuttingand separating the part from the substrate was simulated，and the impact of stress release was predicted. Analysing the impact of scanning strategies and scaning speeds on LPBF thermal-mechanicalcoupling behaviour，it was found that the horizontal Z-type scanning strategy resulted ina 24.0% reduction in maximum displacement and a 13.6% reduction in maximum residual stress compared to the vertical scanning strategy.When the scanning speed was increased from 0.8m/s to 1.6m/s ，the maximum displacement decreased by 6.4% and the maximum residual stress decreased by 5.2% . This paper provides scientific guidance for controlling LPBF residual stress and deformation.

Keywords：full-scale thermal-mechanical coupling;LPBF;residual stress;deformation;stress release;numerical simulation

1 序言

金属增材制造技术可以实现三维复杂结构件的快速制造，是引领第三次工业技术革命的核心技术之一，具有个性化、自动化等优势[1。（剩余12902字）