Evaluation of Welding Eigenstrain Characteristics and Its Application to the Bead Flush Method

焊接残余应力的测量是评定焊接结构完整性的重要内容之一。到目前为止，研究者已经提出了一种新的无损评估方法焊接残余应力称为焊道齐平法，并确认其实用性简单的焊接板的数值模拟和实验。在该方法中，本征应变是通过反分析确定的释放应变过程中删除焊缝的钢筋。然后，残余应力计算简单的有限元分析使用上述确定的本征应变。为使该方法具有更广泛的适用性和更高的精度，在反分析中应事先准确确定本征应变场。因此，在本研究中，一个概念，如何确定的解集的特征应变的反分析。在此基础上，通过热弹塑性分析，研究了焊接特征应变的影响因素，明确了焊接特征应变与残余应力之间的关系。

Measurement of welding residual stresses is one of important tasks to assess the structural integrity of welded structures. By now, the investigator has proposed a new nondestructive evaluation method of welding residual stresses called the bead flush method, and confirmed its utility for simple welded plates by numerical simulations and experiments. In this method, eigenstrains are determined by the inverse analysis using released strains measured during removing reinforcement of weld. And then residual stresses are calculated by simple FEM analyzes using eigenstrains determined above. For wider applicability and higher accuracy of this method, eigenstrain field should be determined accurately beforehand in the inverse analysis. Therefore, in this research, a concept how solution sets of eigenstrains are determined in the inverse analysis is proposed. Based on this concept, influencing factors of welding eigenstrains are investigated and relations between welding eigenstrains and residual stresses are made clear by the thermo-elasto-plastic analysis.