提出了一个考虑应力集中和疲劳极限影响的缺口件频域随机振动疲劳寿命估算方法。首先进行随机振动分析,得到应力响应功率谱密度,用疲劳缺口系数考虑孔边应力集中的影响;然后采用三参数S-N曲线近似公式在频域内进行疲劳寿命估算,考虑疲劳极限的影响。算例结果表明:考虑应力集中和疲劳极限影响的带孔板频域随机振动疲劳寿命估算结果与实验值非常接近。
A frequency domain method for predicting the fatigue life of notched specimens under random vibration loading is presented. The effects of stress concentration and fatigue limit on life prediction are considered in this approach. Firstly, the stress response power spectral density is obtained by random vibration analysis and the influence of stress concentration is calculated by fatigue notch factor. Then, the fatigue life is calculated with a three parameters S-N curve in the frequency domain, considering the effect of the fatigue limit on the fatigue life. Examples demonstrate that, considering the influences of stress concentration and the fatigue limit, the predicted results of the fatigue life of the notched plate are in agreement with the experimental data.