爆炸复合321/Q370qD双金属板对接接头的疲劳性能

采用轴向脉动拉伸疲劳试验,研究了爆炸复合321/Q370qD双金属板对接接头的疲劳性能。通过数理统计计算,获得了50%及97.7%两个置信度下试验材料的S—N曲线方程及据此确定的疲劳强度(2×10~6次),两个置信度下的疲劳强度均高于设计指标。对疲劳试样断口进行了观察,结果显示:疲劳裂纹大都起始于复合板对接接头的基层,个别起始于复层;裂纹稳定扩展区具有明显的疲劳辉纹,瞬断区具有典型的韧窝特征。断裂力学分析表明:疲劳裂纹起始于复合板不同组分的驱动力与复合板对接接头不同组分的循环屈服强度和弹性模量的乘积有关。

Fatigue Properties of Explosive Bonded 321/Q370qD Double-layer Metal Laminate Butting Weld Joints

Through axial pulse-tension fatigue test, fatigue properties of explosive bonded 321/Q370qD double-layer metal laminate butting weld joints were studied. The fatigue S- N curves and fatigue strength （2 ×10^6 cycles）under the confidence degree of 50 G and 97.7 G were attained by mathematical statistics calculation, and fatigue strength under two different confidence degrees was both higher than designing value. Specimen fracture surface were observed and the results manifested that most of fatigue cracks initiated from base-layer of the bonded plate butting weld joints and individual from clad. Some obvious fatigue striations and typical dimples could be seen at stable crack growth district and final fracture zone respectively. Fracture mechanics analysis indicated that the driving force of which component fatigue crack started from was relevant to products of cyclic yield strength and elastic modulus of different components of the bonded plate butting weld joints.