Numerical simulation study on the mechanical properties and failure of laser spot welding joint
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摘要: 测试了三种形状的激光焊点在拉伸、剪切、剥离工况下的静态和动态力学性能,分析了点焊焊缝的显微组织特性和硬度分布情况。结果表明,焊点形状与焊点力学性能密切相关,C型焊点整体性能更优;焊点强度随加载速率的增加而发生塑性强化,加载速率越大,塑性强化越明显;焊缝整体分布均匀,过度平滑,融合区和热影响区硬度高。基于LS-DYNA焊核合力失效准则,研究了激光点焊接头失效数值仿真方法,明确了等效焊核直径用于模拟激光点焊失效方法的有效性。Abstract: The static and dynamic mechanical properties of three kinds of laser welded joints under tensile, shearing and peeling conditions were tested, and the microstructure characteristics and hardness distribution of the spot welded joints were analyzed. The results show that the shape of solder joints is closely related to their mechanical properties, and the overall properties of C-type solder joints are better. The strength of solder joints is plastically strengthened by the increase in loading rate, and the greater the loading rate, the more obvious the plastic strengthening is. The overall distribution of welding seam is uniform and excessively smooth, while the hardness of fusion zone and heat affected zone is high. Based on the LS-DYNA failure criterion, the numerical simulation method of laser spot welding joint failure is studied, and the effectiveness of equivalent core diameter used to simulate laser spot welding failure is clarified.
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表 1 DC04材料参数
Table 1. Material parameters of DC04
密度/(t·mm−3) 弹性模量/MPa 泊松比 屈服强度/MPa 硬化指数 7.8×10−9 210000 0.3 130 228.09 -
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