基于振动信号的机械密封金属波纹管疲劳分析

Fatigue Analysis of Mechanical Seal Metal Bellows Based on Vibration Signal

针对"S"型金属焊接波纹管振动疲劳失效问题,采集相关工况下的振动信号,使用短时傅里叶变换编辑信号的方法识别损伤区间,并在区间端点等距插值拼接信号,得到用于零件疲劳分析的编辑信号。对原始信号和编辑后的信号用雨流计数法统计损伤循环次数,并求出信号的平均能量;将编辑信号加载至波纹管,通过仿真计算进一步验证,得到了编辑信号与原始信号影响下波纹管的疲劳损伤分布云图;并分析不同转速下,振动信号不同应力范围的能量循环次数。结果表明:通过信号缩减得到的编辑信号有效地保留了损伤片段并且缩减了信号的长度,表明基于短时傅里叶变换的缩减信号方法可以有效地缩短疲劳实验的时间,加速研发周期;低转速时波纹管径向应力较大、循环次数较高,更容易发生振动疲劳。

Aimed at the problem of vibration fatigue failure of S-type metal welded bellows,the vibration signals under relevant working conditions were collected,and the short-time Fourier transform was used to edit the signals to identify the damage region,and the signals were interpolated and spliced at the end of the region equidistant to obtain the edited signal for fatigue analysis of parts.For the original signal and edited signal,the number of damage cycles was counted by the rain flow counting method,and the average energy of the signal was calculated.The edited signal was loaded into the bellows,which is further verified by the simulation calculation,and the damage distribution nephogram of the bellows under the influence of the edited signal and the original signal was obtained.The energy cycle of the vibration signal in different stress ranges under different rotational speeds was analyzed.The results show that the edited signal obtained by signal reduction effectively retains the damage segment and reduces the length of the signal,which indicates that the signal reduction method based on short-time Fourier transform can effectively shorten the time of fatigue experiment and accelerate the research and development cycle.At low speed,the radial stress of bellows is larger and the number of radial large stress cycles is higher,and the bellows are more prone to vibration fatigue.