基于DIC的拼焊板焊缝性能识别方法及验证
A novel method for measuring the weld property of tailor welded blanks based on DIC
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摘要: 提出一种新的拼焊板焊缝参数识别方法——分区法.根据垂直焊缝方向次应变不同,将焊缝区分为焊缝和热影响区.采用数字图像相干技术,获取焊缝失效时拼焊板表面的应变场.建立了焊缝性能参数计算模型,分别计算出焊缝的强度系数和应变硬化指数.为验证分区法的有效性,针对纵向激光拼焊板单向拉伸试验,将理论计算结果嵌入有限元分析中,获得拉伸载荷-位移曲线,与混合法及试验结果比较.结果表明,分区法比较接近试验结果,具有较高的精度.Abstract: A novel method,weld division method,was proposed to measure the mechanical properties of the weld zone in tailor welded blanks (TWBs). The weld zone was divided into the weld and heat affected zone according to the different minor strains in the direction perpendicular to the weld. The digital image correlation technology was employed to capture the strain filed in the TWBs surface when the weld failure occurred. A theoretical model was established to calculate the strength coefficient K and strain-hardening exponent n based on the previously achieved minor strain. To verify the proposed method,the curves of load vs. displacement were produced using finite element method by implementing the parameters from the division method, during uniaxial test of longitudinal weld in laser TWBs. Compared with the results from the rule of mixtures,those from the division method were closer to the experimental results, which indicates that the division method was more accurate.