复材-金属混合结构螺栓连接柔度预测方法研究

Research on method for flexibility prediction of composite-metal bolted joints

复材-金属混合结构的螺栓连接柔度分析是混合结构内力分布求解和连接强度设计的基础。首先梳理了常用的机械连接柔度预测公式;然后利用这些公式对3种单钉单剪连接构型的柔度进行预测,并与试验结果进行对比。结果显示,Huth公式和Grumman公式的预测精度比Boeing公式和Liu-Mao公式高,更适合复材-金属混合连接柔度快速预测。预测结果同时也表明,上述两个公式对金属板厚度小于3 mm的复材-金属板混合连接的预测误差均不超过20%。为了进一步减小混合连接的预测误差,建立了精细有限元模型,模型考虑了金属材料的塑性,选取合理的螺栓预紧力和摩擦系数,获得了与试验结果非常接近的载荷-变形曲线,使该类薄、厚材料混合连接的柔度预测误差减小至0.61%。

The flexibility prediction of bolted joints of composite-metal is the basis for the internal force distribution analysis and connection strength design of hybrid structures.The commonly used mechanical joint flexibility prediction formulas are sorted out,and then these formulas are used to predict the flexibility of three single-nail single-shear connection configurations,and the accuracy of the prediction is evaluated by comparing with test data.The results show that the prediction results of Huth formula and Grumman formula are more accurate,and they are more suitable rapid analysis methods for the flexibility prediction of composite-metal hybrid connections.The prediction results of the flexibility formula also show that the above two formulas have a prediction error of no more than 20%for thin thickness hybrid joints with 3 mm metal plate.In order to further reduce the flexibility prediction error of the thin-thickness hybrid joints,a fine finite element model is established considering the plasticity of the metal material,and using a reasonable bolt preload and friction coefficient.A forecast result which is pretty compliance with testing Load-deformation curve is obtained.The flexibility prediction error of the thin thickness hybrid joints is reduced to 0.61%.