裂纹深度和强度组配对焊接接头断裂性能的影响

利用弹塑性有限元计算和三点弯曲试验对不同裂纹深度，不同强度组配焊接接头试样的断裂性能进行了研究，着重讨论了裂纹深度和组配的不同对焊接接头试样加载过程中塑性区形状及大小，深浅裂纹分界点，抗断性能，裂纹尖端张开位移ＣＴＯＤ，Ｊ积分的影响。结果表明，裂纹越浅。加载时塑性区域大，断裂韧性值越高，高组配焊接接头试样加载时由于塑性区扩展到母材而具有较大的塑性区，低组配焊接接头试样加载时塑性区被抑制在焊缝中，尺

Influence of strength matehing ^nd crad^ depth on fracture properties for welded joints

By using elasto-plastic finite element calculation and three point bending test,the in-fluence of strength matching and crack depth on fracture properties are investigated. The mainpoints of this paper are the influence of strength matching and crack depth on the plasticzone, boundary value of depth and shallow crack behaviour,fracture resistance propertical,cracktip opening displacement CTOD,and J-integral in loading processes for welded joint speci-mens,The results show that the plastic zone becomes large when the crack depth turns short,and the fracture toughness turns high, the plastic zone of overmatch joint specimens are largerthan that of undermatched joint specimens in loading processed at the same CTOD value,be-cause the plastic zone of overmatched joint spedens are extend to the base metal but that ofundermatched joint specimens are restricted in the welded seam, Overmatched joint specimensmay more easily show the fracture behaviour of shallow crack than undermatched joint speci-mens, while the two sorts of joint specimens have the same crack length. Therefore, the frac-ture-resistent capability of overmatched weld is better than that of undermatched weld.