为了获取并分析多元连杆的冲击力以及各传力路径上的应变响应特征,采用气炮、悬臂落锤、液压等3种冲击加载方法对发动机多元连杆进行冲击加载.对冲击力和冲击应变响应曲线进行了时间域和频率域的特征分析,获取了冲击力和应变响应的波形特征和频谱特征.通过与静载应变响应的对比获得动静响应系数,以及动静响应系数随波形宽度的变化规律.结果表明:在气炮、悬臂落锤、液压等3种冲击力的波形特征近似的情况下,在频谱上反映出各自不同的频率成分.在各传力路径上的冲击应变响应,除了响应幅值不同外,其余波形特征如峰值特征和频谱特性均较为一致.各应变之和作为连杆冲击力测试方法的表征参数,随波形中高频成分的增多,动静响应系数逐步增大.在进行多元连杆冲击载荷标定时,需要充分考虑所测试冲击力的载荷特征,选取合适的冲击载荷标定或者静载荷标定方法.
To obtain and analyze impact force and the strain response characteristics of each force transmission path of the multi-element connecting rod,three shock loading methods,including air gun,cantilever drop hammer,and hydraulic,were used to apply impact load on the multi-element connecting rod of an aeroengine.The time and frequency domain characteristics of the impact force and strain response curves were analyzed,and the waveform and spectrum characteristics of the impact force and strain response were obtained.By comparing the dynamic strain with the static strain,the dynamic-static response coefficients and their variation laws with the waveform width were obtained.The results show that the impact force waveform characteristics of the three methods are similar,different frequency components are reflected in the respective frequency spectrum.Except for the difference in response amplitudes,other waveform characteristics of the impact strain response on each force transmission path,such as peak and spectrum characteristics,are relatively consistent.The sum of all strains is used as the characteristic parameter of the connecting rod impact force test method;with the increase of high-frequency components in the waveform,the dynamic-static response coefficients gradually increase.When calibrating the impact load of a multi-element connecting rod,it is necessary to fully consider the load characteristics of the impact force and select the appropri-ate impact load calibration or static load calibration method.