螺栓连接对结构模态及传递特性影响研究

针对螺栓刚度及预紧力对装配体模态、传递函数影响较大而在设备装配中因处理困难常被忽略问题，利用有限元计算、试验结合对比方法分析、研究。用ANSYS软件预应力模态分析及谐响应分析对装配体进行仿真计算；对三种刚度螺栓分别施加相同预紧力，对钢制螺栓施加六组不同预紧力进行试验；分析对比计算值与试验值误差。结果表明，忽略接触阻尼的计算值与试验值存在最大误差约15%；同一预紧力时，随螺栓刚度的提高固有频率呈增大趋势，各阶频率的最大变形量随之增大；随预紧力的增大，结构传递函数趋于明朗化。

Research on the effect of bolt to structural modal and transfer characteristics

Bolt stiffness and pre-tightening force have great impact on structural modal and transfer function, which are often ignored in the actual assembling because of the difficult processing. By comparing the finite element calculation data and test data of three kinds of bolts with different stiffness under different pre-tightening force, changes of structure modal and transfer function are analyzed. First simulation analysis and calculation are made by ANSYS software pre-stressed modal and harmonic response. Then the tests of three kinds of bolts with different stiffness bolts are done under the same pre-tightening force, and the steel bolt is tested under six groups of pre-tightening force. Finally, the differences between calculation data and test data are studied. The study results show that the calculation value differs about 15% from test data because the contact damping is ignored. Under the same pre-tightening force, the natural frequency is increasing with the increasing of the bolt stiffness, but the maximum distortion also increases. The structure transfer function will be easier to find as the pre-tightening force increasing.