复合材料螺接性能的影响因素研究

Study on Factors Influencing the Performance of Composite Bolted Connections

利用有限元软件ANSYS建立了单钉双剪复合材料单拉接头的1/2模型,研究了钉孔配合、螺栓预紧力和接触面间摩擦对接头的强度等性能的影响。设计了若干实验,证明有限元模型是有效的,其计算误差控制在10%以内。有限元计算结果表明:小干涉量的过盈配合能极大地提高接头的强度,与3%间隙量相比,最优干涉量下接头强度可提高36.5%;适当的螺栓拧紧力矩也可提高接头的强度;接头中被连接板间的摩擦对接头强度也是有利的,但在一定接头尺寸条件下,摩擦力的增大有可能会改变接头的破坏模式。以上研究成果为复合材料多钉连接钉载分配均匀化的参数化分析提供了一个突破口,这也是本文后续研究的一个内容。

A doublelap singlebolt composite joint is designed as a model using the ANSYS finite element （FE） package. The joint is subjected to longitudinal tensile loads and half of the model is numerically analyzed. Three key factors influencing the performance of the connection are studied, including the bolthole fit, bolt pretightening force and the friction between the contacting plates. The model is then validated by several experiments, with computational errors of less than 10 %. Analytical results show that a small magnitude of interference substantially improves the strength of the joints. With optimum inter- ference, there is an increase of joint strength up to 36.5% as compared with the 3% clearance fit scenario. An adequate tightening torque also enhances the joint strength. The friction between the connecting laminates is also beneficial to increasing the strength. The failure mode varies with the friction coefficients between the plates for specific connection sizes. These findings signifies a beginning for the parametric analysis on load distribution uniformization in multibolted composite joints, which will be explored in subsequent studies.