This paper aims to develop a high-efficient finite element (FE) model by combining the equivalent boundary condition method (EBCM) and dynamic mesh method (DMM) for accelerating the thermo-mechanical simulation of additive manufacturing by powder bed fusion (PBF). EBCM and DMM take advantage of the strong non-linear phenomenon in the thermo-mechanical affected zone (TMAZ) by simplifying the temperature boundary conditions and optimizing the local mesh density, respectively. In detail, EBCM can reduce the difficulty of convergence in computing, while DMM can reduce the scale of stiffness matrix. The experimentally calibrated lattice Boltzmann method (LBM) firstly is used to produce the equivalent temperature function in TMAZ as the thermal input conditions of the FE model. The thermo- mechanical responses of several PBF deposits under different process parameters are predicted by the developed model, presenting good agreement with experiment data in terms of in-situ temperature and residual stress. Compared with the normal model, the novel high-efficient model notoriously cuts the computation cost without compromising precision. This study provides an important simulation concept for high-efficient FE analyses with high fidelity of the AM technology.

本文旨在通过结合等效边界条件法 (EBCM) 和动态网格法 (DMM) 来开发一种高效的有限元 (FE) 模型，以加速粉末床融合 (PBF) 增材制造的热机械模拟。EBCM 和 DMM 分别通过简化温度边界条件和优化局部网格密度来利用热机械影响区 (TMAZ) 中的强非线性现象。具体来说，EBCM可以降低计算收敛的难度，而DMM可以降低刚度矩阵的规模。实验校准的晶格 Boltzmann 方法 (LBM) 首先用于在 TMAZ 中产生等效温度函数作为有限元模型的热输入条件。开发的模型预测了几种 PBF 沉积物在不同工艺参数下的热机械响应，在原位温度和残余应力方面与实验数据非常吻合。与普通模型相比，新的高效模型在不影响精度的情况下降低了计算成本。本研究为具有高保真 AM 技术的高效 FE 分析提供了重要的模拟概念。