基于刚度退化的振动传递路径系统的可靠性分析

Reliability sensitivity analysis of a vibration transfer path system based on stiffness degeneration

结构系统在振动过程中必定会伴随刚度退化,通过将刚度累积损伤理论引入振动微分方程,结合随机有限元法和可靠性基本理论,推导出在考虑刚度退化下具有随机参数的振动传递路径系统的传递可靠度和可靠性灵敏度数学模型。通过对某一动力伺服刀架进行分析,得到了该刀架系统在随机参数均值处的可靠度和其对各随机参数的灵敏度随激振频率和时间的变化规律。结果表明刚度退化会引起频域内的可靠度及其对各随机参数的灵敏度走势随时间发生偏移,可靠度对各随机参数的灵敏度峰值随时间发生波动,且零时刻频域内的灵敏度峰值不一定是时域内极大值。通过采用Monte Carlo法进行验证,进一步证明了该方法的准确性。通过对敏感参数优化,可以增强系统稳定性,也可以有效地预防因共振区域随时间改变而引发的共振失效问题。

A structural system must undergo stiffness degradation during the vibration process.By introducing the stiffness cumulative damage theory into the vibration differential equation,combined with the stochastic finite element method and the reliability theory,a mathematical model of the reliability and reliability sensitivity of the vibration transfer path system with random parameters considering stiffness degradation was obtained.The reliability and the reliability sensitivity to each random parameter of a tool holder system at the random parameter mean with the excitation frequency and time were obtained.The results show that the stiffness degradation caused the reliability and reliability sensitivity to random parameters to shift with time;the reliability sensitivity peak fluctuates with time;the peak value in the frequency domain at the initial time is not necessarily the maximum value in the time domain.The accuracy of the method was further proved by the Monte Carlo method.System stability can be enhanced by optimizing sensitive parameters;the resonance failure caused by the change of the resonance region with time can be effectively prevented.