螺栓法兰连接结构的拉压不同刚度动力学模型

Simplified Dynamic Model with Different Tensile and Compressive Stiffness for Bolted Flange Connections

由于螺栓法兰连接结构轴向拉压刚度不同,针对这一特性引入拉压刚度不同的双线性弹簧单元,提出两自由度拉压不同动力学机理模型,使用区域法进行了动力学响应的解析推导;同时开发了自适应递归过零检查算法对模型的冲击响应进行数值计算。理论分析与数值模拟结果均表明,拉压不同刚度动力学模型在横向冲击荷载作用下产生横纵耦合振动响应,且输出了比线性梁模型更大的变形以及内力响应,说明线性梁模型获得的荷载结果可能偏小,这一结论对于提高螺栓法兰连接结构的安全可靠性具有重要意义。

Static mechanical responses of the bolted flange joint are firstly discussed,which reveals the different tensile and compressive stiffness in the axial direction.Accordingly,to represent this important feature,bilinear springs are employed,and a schematic nonlinear dynamic model with 2 DOFs is developed,through which the impact behavior of the joint is analytically investigated.To decrease the energy dissipation,recursion and dichotomy algorithm are employed to construct relevant numerical solutions.A special type of dynamic behavior,coupling vibration in the transverse and longitudinal directions,is observed in both analytical derivation and numerical solution.Furthermore,the internal force response of the proposed model is bigger than that corresponding conventional linear model,which implies the risk of the conventional dynamic model.This conclusion is important for the safety and reliability evaluation for bolted flange joints.