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利用有限元方法,对Fe-Mn-Si记忆合金平板激光对接焊的温度场和应力场进行三维数值模拟.根据激光焊接特点,建立表面高斯热源和锥形体热源结合的复合热源模型,并编制APDL子程序实现焊接热源的加载和移动.结合材料非线性、相变潜热、边界换热条件等因素,通过模拟计算得到焊接过程中瞬态温度场分布和熔池尺寸,并分析整体温度场分布、焊接热循环特性.焊缝熔合线和尺寸的模拟结果与实际结果吻合良好,验证了模型的正确性.在温度场计算结果基础上,利用间接耦合法,对Fe-Mn-Si记忆合金激光焊的动态应力场和残余应力进行模拟计算,得到焊后最大残余应力为247 MPa,接近其屈服强度.
The finite element method was used to simulate the temperature field and stress field of Fe-Mn-Si memory alloy flat-plate laser butt welding.According to the characteristics of laser welding, a composite heat source model combining surface Gaussian heat source and cone body heat source was established and APDL Subroutine to realize the loading and moving of welding heat source.According to the material non-linearity, phase transition latent heat and boundary heat transfer conditions, the transient temperature field distribution and the size of the weld pool during welding are obtained, and the overall temperature field distribution is analyzed, And the thermal cycling characteristics of the weld.The simulation results of weld line and size agree well with the actual results, which proves the correctness of the model.On the basis of the calculation results of temperature field, the laser welding of Fe-Mn-Si memory alloy The dynamic stress field and the residual stress are simulated and the maximum residual stress after welding is found to be 247 MPa, which is close to its yield strength.