静/动加载下单搭螺栓连接复合材料板的刚度变化规律

Stiffness Change Law of Single-Lap Bolted Joint Composite Plates under Static/Dynamic Loading

关键词:  螺栓连接  复合材料  失效行为  刚度  预紧力

Key words:  Bolted joints  Structural composite  Failure behavior  Stiffness  Preload

摘要:

为研究单搭接螺栓连接复合材料板在准静态拉伸和动态加载下的刚度变化规律，以单搭接螺栓连接T300碳纤维增强复合材料（CFRP）板为对象，测试了准静态拉伸和动态加载条件下螺栓连接复合材料板的位移载荷响应，分析了结构失效情况及刚度变化规律。基于通用有限元软件建立了螺栓连接复合材料板的刚度退化有限元模型，并通过编写子程序定义材料的损伤准则和材料性能退化模型，探究结构刚度退化影响因素。结果表明：有限元刚度退化模型预测的位移载荷响应与试验测试结果基本一致；当螺栓接头施加的预紧力矩从0.5N·m增加到10N·m时，高准线性阶段的极限载荷和平均刚度将大大增加；当动态载荷比为0.8时，螺栓连接复合板的动态刚度瞬态值提升30%左右，动态刚度平均值可提高20%左右；当动态载荷比为0.5时，动态刚度瞬态值提升30%左右，动态刚度平均值提高8%左右。

Abstract:

In order to study the stiffness change law of single lap bolted composite plates under quasi-static tension and dynamic loading， taking T300 carbon fiber reinforced composite （CFRP） plate connected with single lap bolt as the object， the displacement load response of bolted composite plate under quasi-static tension and dynamic loading was tested， and the structural failure and stiffness change law were analyzed. Based on the general finite element software， the stiffness degradation finite element model of bolted composite plate was established and the damage criterion and material performance degradation model were defined by writing subroutines， which were explored to the influencing factors of structural stiffness change law. The results show that the displacement load response predicted by the finite element stiffness degradation model is basically consistent with the experimental results. When the pre tightening torque applied by the bolted joint increases from 0.5N·m to 10N·m， the limit load and average stiffness in the high quasi linear stage will increase greatly. When the dynamic load ratio is 0.8， the transient value of dynamic stiffness of bolted composite plates can be increased by about 30%， and the average value of dynamic stiffness can be increased by about 20%. When the dynamic load ratio is 0.5， the transient value of dynamic stiffness can increase by about 30%， and the average value of dynamic stiffness increases by about 8%.