The influence of the bolt pretension force on the dynamic characteristics of bolted joints was studied using a double bolt joint with an equivalent single DOF model based on the lumped parameter method near the first mode. Then, the equivalent dynamic parameters were obtained for various bolt preloadings using modal and excitation tests. The equivalent nonlinear dynamic parameters for the joint were then identified using the force-state mapping method for various pretension forces. The results show that the joint nonlinearity increases with decreasing pretension force. Therefore, the nonlinear joint dynamics must be considered for low pretension forces.
摘要 为研究预紧力对螺栓结合部动力学特性的影响, 该文选择一种双螺栓结合部试件作为研究对象, 通过理论推导利用集中参数法在试件一阶模态处建立了单自由度简化模型; 通过模态实验获得了不同螺栓预紧力下结构一阶动力学特性的变化情况; 在激振实验的基础上, 利用力状态映射法对结合部在不同预紧力下非线性等效动力学参数进行了辨识。结果表明：结合部非线性会随预紧力降低而增强。在预紧力较低时, 对结合部进行准确动力学建模需要考虑非线性因素的影响。