3σ准则应用对结构疲劳损伤评价的影响分析

摘要

The 3σclipping rule is used in a random vibration process in the time-domain and the frequency-domain. In this paper, the frequency-domain methods for the fatigue damage accumulation analysis are used to evaluate the effects of the 3σclipping rule on the results of fatigue damage accumulation analyses. A narrow-band model described by the Rayleigh distribution and four typical modified approaches is employed to analyze the fatigue influence factors. Numerical simulations show that the fatigue damage accumulation corresponding to the 3σclipped is only about 70%of the total fatigue damages(with material fatigue parameter m=6). The influence factor analysis based on the narrow-band model can be applied approximately for wide-band random processes.%工程研究中经常要应用3σ准则来实现随机振动过程的时域、频域转换。文章应用疲劳损伤分析的频域方法，讨论了3σ准则的应用对于振动疲劳损伤累积评价结果的影响。应用满足Rayleigh分布的窄带模型及其4种典型的修正方法分析疲劳影响因子，数值模拟结果表明，3σ截断后的疲劳损伤累积仅占全部疲劳损伤累积的约70%（取m=6），与材料疲劳参数m有关，且基于窄带模型的疲劳影响因子分析方法具有一定程度的通用性。