起重机金属结构裂纹修复后再生裂纹的探讨

通过一台门座起重机金属结构裂纹的修复， 分析了修复后又产生裂纹的原因， 从而提出在裂纹修复中应该注意的问题。

疲劳裂纹钻孔止裂技术研究

结构在循环荷载作用下可能产生疲劳裂纹,裂纹通常源于应力集中部位,在往复荷载作用下会不断扩展直至结构破坏。对于带有贯穿型裂纹的钢板,钻孔止裂是一种很好的临时修复措施。钻孔止裂是在裂纹尖端钻孔,以消除局部的应力集中,阻止裂纹的继续扩展。对特定的疲劳裂纹,止裂孔的直径会影响钻孔止裂的效果。通过弹塑性有限元分析,确定不同直径止裂孔的孔边最不利应变幅值,利用局部应力应变——寿命法,分析和比较了不同止裂孔直径对疲劳裂纹再生寿命和止裂效果的影响。

冷扩孔并置入栓钉技术止裂效果研究

采用有限单元法对冷扩孔并置入栓钉处理措施进行数值模拟,并对循环荷载下止裂孔孔边应力、应变状态的分析表明,冷扩孔并置入栓钉降低了应力集中部位的应变幅,从而延长疲劳裂纹在止裂孔边的再生寿命,栓钉直径均会影响钻孔止裂相关技术的止裂效果。

The mechanism and criterion of tectonic zone around karstic collapse column reactivation-induced water-conducting

In order to study the mechanism of tectonic zone around karstic collapse col-umn reacts to leak water and prevent water invasion in mine. According to the character of the surrounding cracks- penetrated water KCC, The fracture mechanics theory can be used to study the propagation and perforation process of cracks and hitches around the KCC. The criterion of crack start rupture and the length of secondary crack and criterion of crack propagation have been attained. The influencing factors of KCC reacts to water con-duction were analyzed.