吊钩断裂原因分析

某起重机吊钩使用1a(年)多突然断裂。采用宏、微观检验方法,对吊钩断裂失效原因进行了分析。结果表明,吊钩断裂的直接原因是由于低周疲劳所产生的裂纹,在外应力的作用下扩展所致;通过对吊钩材料化学成分分析和吊钩受力进行理论计算,认为材料选择不当,强度偏低是造成吊钩断裂的另一重要原因。

Evaluation of stress intensity factors of thin AZ31B magnesium alloy plate under biaxial tensile loading

Stress intensity factors of thin AZ31B magnesium alloy sheet under biaxial tension loading were analyzed by modified Dugdale model. K-values with crack angle of 90° obviously show that there is no influence of the loading condition in Mode-I. In the 45° case, K1 values are obtained within 10% errors when they are calculated by modified Dugdale model under biaxial loading. It is concluded that the modified Dugdale model is one of effective ways to evaluate stress intensity factor of AZ31 magnesium alloy sheet appropriately.