基于非线性累积损伤的随机振动疲劳寿命分析

预测承受随机载荷结构件的疲劳寿命是一个复杂的问题,应用Miner线性损伤准则经常会得出偏于冒险的寿命预测。非线性累积损伤理论考虑了加载顺序对疲劳寿命的影响,精度更高,但计算繁琐,且未能用于频域寿命计算。文中给出了一种基于非线性累积损伤的随机振动疲劳寿命分析方法,该方法将频域疲劳寿命的预估结果平分为若干段,考虑顺序效应对每一段结果进行修正并叠加,得到修正的振动疲劳寿命结果,通过简单试验件试验验证了该方法的准确性,对于某加筋板结构在动力学准确建模、多轴应力等效的基础上进行寿命估算,结果证明了方法的有效性和工程可用性。

Random Vibration Fatigue Life Analysis Based on Nonlinear Cumulative Damage

problem to predict the fatigue life of structures subjected to random loads. The simplest and most widely used damage model is the Miner''s linear damage criterion. However, the application of this criterion often leads to the risky life prediction. Nonlinear cumulative damage theory takes into account the effect of loading sequence on fatigue life, with higher accuracy, but it is cumbersome and can not be used for frequency domain life calculation. In this paper, a modified algorithm of frequency domain fatigue life prediction based on nonlinear cumulative damage is presented. The accuracy of the algorithm is verified by simple test. For a stiffened plate structure with accurate dynamics modeling, the validity of the method and the engineering usability are proved.