力学性能非对称焊接接头疲劳裂纹扩展规律

研究了硬对软（ＣＳ）、软对硬（ＣＨ）和软硬中（ＳＨＭ）三种典型的力学性能非对称焊接接头疲劳裂纹扩展规律．结果表明：力学性能非对称性对焊接接头的疲劳裂纹扩展规律有很大影响．起始裂纹在软区的硬对软力学性能非对称焊接接头，起始裂纹越靠近硬区，疲劳裂纹扩展速率越快；起始裂纹在硬区的软对硬力学性能非对称焊接接头，起始裂纹越靠近软区，疲劳裂纹扩展速率越慢；起始裂纹在硬区的软硬中力学性能非对称焊接接头，硬夹层宽度越窄，疲劳裂纹扩展速率越慢．

A Study on Fatigue Crack Growth in Welded Joints with Non Symmetrical Mechanical Properties

The fatigue crack growth in three typical welded joints, hard soft (CS), soft hard (CH) and soft hard medium (SHM) ones, with non symmetrical mechanical properties has been studied. It is shown that the effect of the non symmetrical mechanical properties on the crack growth is significant. For CS joint, it is found that when the initial crack is located in soft zone, the closer the initial crack is to the soft hard interface, the quicker the fatigue crack growth rate is. For CH joint, when the initial crack is located in hard zone, the closer the initial crack is to the hard soft interface, the slower the fatigue crack growth rate is. For CHM joint, when the initial crack is located at the center of the hard layer, the narrower the hard layer width is, the slower fatigue crack growth rate is.