异种不锈钢激光焊缝材料的动态本构关系

Constitutive equations for dissimilar stainless steels laser-welded materials

利用等应变测试法获取了304及316L激光焊接焊缝材料的准静态应力应变曲线,发现焊缝材料具有明显的细晶硬脆化趋势。利用SHTB技术对304、316L及焊接构件材料高温动态力学性能进行了研究。根据动态实验数据对不锈钢304及316L母材应变率及温度相关的Johnson-Cook本构方程参数进行了拟合。利用LS-DYNA建立了SHTB动态拉伸实验数值模型,发现了在应力波加载初始阶段由于结构效应及材料阻抗不匹配引起的应力不平衡现象。通过动态实验与数值模拟相结合的方法确定了焊缝材料的应变率相关本构参数。

The stress-strain curves of the 304 and 316L stainless steels laser-welded materials were obtained by using the equal strain test method.And obvious hardening behaviors due to the tiny crystal of the welded materials were noticed.The dynamic mechanical properties of the 304,316L and welded structure materials were experimentally investigated by SHTB at elevated temperature.Constitutive parameters for the 304 and 316L stainless steels were fitted according to dynamic experimental data.The numerical simulation for the welded structure materials in SHTB test was carried out by LS-DYNA and it was found that stress in the structure materials was non-equilibrium at the early loading stage due to material impedance difference.The strain rate-related parameters in Johnson-Cook constitutive equations for the welded materials were obtained by combining numerical calculation and experimental data.