异厚度铝合金薄板激光拼焊应力应变场数值模拟

Numerical simulation on stress-strain field of laser welding aluminum alloy joints with different thickness

利用ANSYS软件对异厚度铝合金激光拼焊的应力应变场进行三维瞬态有限元分析。为了提高计算精度和效率,采用过渡网格划分形式以保证焊缝处网格足够细小。定义弹性模量E,线膨胀系数lα,泊松比μ等随温度变化的材料力学参数值。指定塑性分析选项为经典的双线性随动强化(BKIN),边界条件约束焊件的自由度以模拟夹具的作用。结果表明,由于厚度不同,薄厚两板应力应变场存在差异,薄板焊缝附近的应力场范围较大,变形比厚板复杂且比厚板大。利用小孔释放法检测异厚度铝合金激光拼焊板的残余应力,将模拟值与实测值进行对比分析,结果显示模拟值与实测值吻合良好。

By finite element code ANSYS,the 3D stress-strain fields of aluminum alloy joints in different thickness made by laser welding were simulated.In order to improve the accuracy and efficiency,transition mesh was used.The effects of temperature-dependent material parameters were considered in the model.The bilinear kinematical hardening(BKIN) was established.Proper restrictions of displacement were applied for simulating effect of clamps.The result of simulation indicates that,the stress-strain field in the thin plate is larger than the thick one.Using hole-drilling technique,the residual stress was measured.It is shown that the simulation results are in accordance with the experimental results.