钉头型式对复合材料层合板机械连接强度的影响

Bearing Strength of Composite Bolted Joints with Different Bolt Heads

通过3种不同铺层比例的复合材料层合板机械连接接头的挤压强度测试,研究了钉头型式对复合材料层合板机械连接挤压力学性能的影响,获得了沉头螺栓挤压强度修正系数。试验数据表明：采用沉头螺栓的复合材料机械接头的挤压强度,可达到采用凸头螺栓的复合材料机械连接挤压强度的90%左右,但接头刚度仅为采用凸头螺栓的复合材料接头刚度的40%~50%。研究采用Hashin失效准则和Tan-Camanho损伤扩展方法,对两种钉头型式的复合材料层合板机械连接接头的挤压失效过程进行了有限元分析,预测了复合材料层合板机械连接接头的偏移挤压强度和极限挤压强度,模型预测值与试验值的误差不超过15%。

The bearing strength of composite-steel bolted joints using protruding and countersunk bolts is tested for three different layups to study the effects of bolt head types on the bearing strength.The bearing strength coefficient of countersunk bolted joint is obtained.Test results show that the bearing strength of countersunk bolted joints is roughly 90%of that of protruding bolted joints,while the corresponding joint stiffness is only 40%—50% of that of protruding bolted joints.Finite element models are generated to numerically analyze the mechanical behavior of composite-steel bolted joints using protruding and countersunk fasteners respectively under in-plane tensile load.The Hashin failure criteria and the Tan-Camanho damage propagation method are adopted.The predicted offset and ultimate bearing strength shows a good correlation to the test results with error less than 15%.