卡箍-管路系统固有特性计算与试验方法

以航空发动机中的卡箍-管路系统为研究对象,基于自主设计的卡箍刚度试验测试装置,对直径为8 mm的卡箍的线刚度和角刚度进行了试验测试。根据实测卡箍刚度,采用线性弹簧对其进行离散化等效处理,并基于自编有限元法建立了卡箍-管路系统的动力学模型。通过试验与仿真所获得的固有频率及频响函数的对比,从而验证了卡箍刚度测定及有限元模型的合理性,并进一步研究了拧紧力矩对卡箍-管路系统固有频率的影响。结果表明:拧紧力矩的增加会导致管路的固有频率增大,且针对所研究的卡箍,当拧紧力矩大于8 N·m时,管路固有频率逐渐趋于稳定。 

Calculation of natural characteristics and experimental methods of the clamp-pipe system

In view of the clamp-pipe system in aero-engine, the linear stiffness and angular stiffness of clamps with diameter of 8 mm was obtained based on self-designed experimental rig. The clamp was discretized into several springs according to the experimental results, and a dynamic model of the clamp-pipe system was proposed based on the finite element method. The measured stiffness of clamps and the finite element model was verified by comparing with the measured and simulated natural frequencies and corresponding frequency response functions. Furthermore, the effect of tightening torque on the natural frequencies of the clamp-pipe system was studied. The results show that the natural frequencies of the pipe increase with the tightening torque. For the clamps studied, the natural frequencies of the pipe gradually become stable value when the tightening torque is greater than 8 N·m.