可调拘束实验测量的焊接凝固裂纹阻力曲线的有限元法修正

FEM MODIFYING THE RESISTANCE CURVE OF WELD METAL SOLIDIFICATION CRACK MEASURED BY TRANS-VARESTRAINT TEST

利用有限元法对横向可调拘束实验进行了数值模拟,得到了不同弯曲应变条件下熔池尾部的局部应变,结果表明:在进行可调拘束实验过程中,焊接熔池尾部确实存在应变集中,从而对实验测得的平均应变即材料凝固裂纹阻力进行了修正.此外, 将横向可调拘束实验模拟得到的局部应变与采用高速摄影和可调拘束相结合测量得到的局部应变进行了对比,能够较好的吻合.同时,计算了不锈钢SUS310焊接凝固裂纹驱动力,并与修正后的阻力曲线进行比较,预测了凝固裂纹敏感性,预测结果与实验结果相符.说明利用横向可调拘束实验结合数值模拟方法,能够定量预测焊接凝固裂纹.

The Trans-Varestraint test was modeled with finite element method (FEM) and the local strains in the trail of weld molten pool were obtained with different bending strains. The results show that there is a strain concentration in the train of weld molten pool during Trans-Varestraint testing and the calculated local strains thus modify the tested average strains, that is the material resistance to weld solidification cracks. Moreover, the calculated local strains agree well with the measured local strains got with the combination of high speed CCD camera and the Trans-Varestraint test. Furthermore, the driving force to the solidification crack of the stainless steel SUS310 was calculated and compared with the modified resistance so that the weld solidification crack was predicted, which agrees well with the experimental results. The results indicate that the weld solidification crack can be predicted with combination of Trans-Varestraint test and FEM.