力学性能不均匀性对焊接接头三点弯曲试样塑性区发展规律的影响

EFFECTS OF MECHANICAL HETEROGENEITY ON PLASTIC ZONES OF WELDED JOINT THREE POINT BEND SPECIMENS

利用弹塑性有限元方法对焊接接头试样在三点弯曲试验中塑性区的发展情况进行了计算。分析了不同的裂纹深度、强度组配、焊缝宽度以及不同位置裂纹的焊接接头试样对塑性区形状发展的影响规律。分析结果显示，不同强度组配和几何特征的焊接接头试样对裂纹尖端塑性区的发展规律有较大的影响。由于裂纹尖端拘束程度的不同会造成塑性区的形状和尺寸的改变，因此在做焊接接头试样三点弯曲试验时，可能会得出与均质材料试样不同的驱动力曲线和材料韧度。

In this paper, an elastic plastic finite element method has been utilized to compute the evolution of the plastic zones in welded joint three point bend specimens. It is analyzed that the effects of the crack depth, strength mis matching, weld width and the crack location on the plastic zones evolution at crack tip. The main results indicate that the strength mis matching and geometry of the welded joint specimens have evident effect on the evolution of the plastic zones. Because the constraint which comes from the above various factors will give an influence on the shape and size of the plastic zone at crack tip, the welded joint specimens may have the different crack growth driving force curve and the material fracture toughness during the three point bend test.