数字图像相关法焊接热影响区应变原位测量及应力计算

提出了焊接热影响区全场高温应变在线测量及评价方法,设计了一种新型具有抗高温烧损、随机分布特征的散斑点阵。为解决焊接电弧强弧光干扰问题,采用脉冲激光辅助光源和近红外窄带滤光系统获取清晰焊缝热影响区散斑图像。针对焊接热影响区焊接变形复杂性,开发了基于二阶形函数与双三次插值的反向组合型Gauss-Newton算法,获得焊接热影响区全场高温应变场。建立多维应力、应变空间加载规律的弹塑性增量本构关系,定量求解焊接热影响区的残余应力分布。结果表明,所研制的焊接全场高温应变视觉测量系统,为焊接接头全场高温应变测量及可靠性评估提供了高效、准确的表征手段。     

In-situ strain measurement and error analysis of arc welding with 2D digital image correlation

The deformation and residual stress generated by the welding process can seriously affect the use of components. As a result, it is very important to understand the evolution of stress and strain during the welding process. The strain measurement method based on digital image correlation(DIC) is an excellent method to detect welding strain and residual stress. The out-of-plane translation and out-of-plane rotation introduce errors to the two-dimensional DIC. In this paper, the causes of errors a...