机械

针对40～68 mm厚板焊接过程中因高热输入引发的变形与残余应力问题，建立热-结构耦合数值模型，系统探究了焊接温度（1600～2400℃）、焊接速度（2～6 mm/s）及板厚参数对焊接质量的综合影响。研究采用Goldak双椭球热源模型描述电弧热源分布，结合非线性傅里叶热传导方程和温度相关弹塑性本构关系，构建了包含热传导、弹塑性力学和热源动力学的多物理场耦合理论框架。通过ANSYS平台实现移动热源的动态模拟，采用生死单元法处理熔池区域激活，并严格控制网格敏感性和时间步长设置以确保计算精度。仿真结果表明，焊接温度对变形和残余应力的影响呈现显著非线性特征；焊接速度的提升能有效抑制热积累；不同板厚表现出明显差异响应。根据研究结果，提出针对不同板厚的动态工艺优化策略：薄板宜采用高温高速组合，厚板需将温度控制在2000℃以下并配合分层焊接工艺。

This study investigates the deformation and residual stress induced by high heat input during the welding of thick plates(40-68 mm). A thermo-mechanical coupled numerical model was developed to systematically analyze the combined effects of welding temperature(1600-2400 ℃), welding speed(2-6 mm/s), and plate thickness on welding quality. The Goldak double-ellipsoid heat source model was employed to characterize the arc heat distribution. By integrating the nonlinear Fourier heat conduction equation with a temperature-dependent elastic-plastic constitutive relation, a multi-physics theoretical framework was established, encompassing heat conduction, elastic-plastic mechanics, and heat source dynamics. The dynamic simulation of the moving heat source was implemented on the ANSYS platform, where the birth and death element method was applied to model the molten pool activation. Mesh sensitivity and time-step controls were rigorously enforced to ensure computational accuracy. The simulation results reveal that the influence of welding temperature on deformation and residual stress exhibits significant nonlinearity. Higher welding speeds effectively mitigate heat accumulation. Plate thickness significantly influences the response. This study proposes dynamic optimization strategies tailored to different plate thicknesses. For thin plates, a combination of high temperature and high speed is recommended, whereas thick plates require temperature control below 2000 ℃ combined with multi-layer welding techniques.