C/SiC陶瓷基复合材料螺栓连接件的振动响应特性及防松性能

通过对C/SiC陶瓷基复合材料螺栓连接件的模态进行计算和试验分析，确定了其模态参数和振动响应特性；然后通过对C/SiC陶瓷基复合材料螺栓连接件进行正弦扫频振动试验，研究了拧紧力矩对螺栓连接件振动性能的影响规律；最后研究了液态聚硼硅氮烷（L-PBSZ）对C/SiC陶瓷基复合材料螺栓连接件防松性能的影响。研究结果表明：一阶和三阶固有计算模态频率与试验模态频率一致，因此可以采用有限元分析方法对C/SiC陶瓷基复合材料螺栓连接件进行振动响应特性分析；采用正弦扫频振动频谱信号差值曲线分析方法可以检测螺栓连接件是否松动；SEM观察表明，L-PBSZ改性的C/SiC陶瓷基复合材料螺栓连接件的螺纹副间形成陶瓷填充体，使得螺纹与螺母间有效摩擦系数和有效摩擦面积增加，因此螺母松脱退出的力矩增大，提高了C/SiC陶瓷基复合材料螺栓连接件的防松可靠性能。

Vibration response characteristics and looseness-proof performances of C/SiC ceramic matrix composite bolted fastenings

Through the computational and experimental analysis on the modal of C/SiC ceramic matrix composite bolted fastenings, the modal parameters and vibration response characteristics were determined. The influence of tightening torque on the vibration performance of bolted fastenings was researched by sine-sweep vibration of the C/SiC ceramic matrix composite bolted fastenings. The influence of liquid polyborosilazanes (L-PBSZ) on the looseness-proof performances of C/SiC ceramic matrix composite bolted fastenings was measured. The results indicate that the first and the third natural frequency of the calculating modal are consistent with that of the experimental modal, so the finite element analysis method can be used for the vibration response characteristics analysis of C/SiC ceramic matrix composite bolted fastenings. The spectrum signal difference curves of sine-sweep vibration can be used to determine whether fasteners come loose or not. The ceramic fillers is observed between the screw pairs of L-PBSZ modified C/SiC ceramic matrix composite bolted fastenings by SEM, and the effective friction coefficient and the effective friction area increase with the nut and the screw, so the loose exit resistance of nut increases, and the looseness-proof performances of C/SiC ceramic matrix composite bolted fastenings are improved.