横向振动试验螺栓预紧力衰减机理及验证

The Attenuation Mechanism and Verification of Bolt Pre-Tightening Force in Transverse Vibration Test

为初步探索固体发动机振动试验过程中螺栓连接松动预紧力与横向振动载荷大小的定量关系,本文采用斜面滑块模型,结合PyCharm编程平台分析螺栓松动预紧力与横向振动载荷的关系,计算得到了不同预紧力下螺栓的临界松动横向载荷,然后搭建横向振动试验装置进行试验,验证计算分析结果的有效性。研究结果认为:1)在短时间的横向振动载荷下要保证螺栓连接不发生松动,预紧力需要高于横向振动载荷幅值的12倍。2)加入毛毡垫引起的螺栓松动为非旋转型松动,螺栓预紧力大小经过一段时间衰减到初始值的百分之八十多;而横向振动载荷引起的螺栓连接松动为旋转型松动,通常使得螺栓预紧力完全消失。分析结果为后续固体发动机振动试验工艺提供参考。

In order to preliminarily explore the quantitative relationship between the pre-tightening force of bolt connection and the transverse vibration load during the vibration test of solid rocket motor,this paper uses the inclined slider model and combines the PyCharm programming platform to analyze the relationship between the bolt pre-tightening force and the transverse vibration load.The critical loose transverse load of bolts under different pre-tightening forces is calculated,and then a transverse vibration test device is built to test and verify the validity of the calculation and analysis results.The analysis results show that:1)The bolt connection under a certain pretightening force has a critical transverse vibration load that makes the threaded connection loose.In order to ensure that the bolt connection does not loose under a short-term transverse vibration load,the pre-tightening force needs to be 12 times higher than the amplitude of the transverse vibration load.2)The bolt looseness caused by adding felt pad in the test is non-rotating looseness,and the bolt preload is attenuated to 80%of the initial value after a period of time,and then tends to be stable;the bolt connection loosening caused by transverse vibration load is rotating loosening,which usually makes the bolt preload completely disappear.The analysis results provide a reference for the subsequent solid engine vibration test process.