基于实测数据的随机振动疲劳寿命预测方法

Method for predicting the random vibration fatigue life based on measured data

为研究随机振动载荷下构件的疲劳特性,采用振动台对试件开展随机振动疲劳试验。通过对试件应变计改装,完成试验过程中试件应变响应载荷测量,并实现试件疲劳过程的实时监测,准确获取了试件疲劳时刻。基于实测时域数据,结合雨流计数法和线性累积损伤理论,预估3种量级下试件的随机振动疲劳寿命。预估值与试验值对比均在3倍分散带内,验证了上述随机振动疲劳寿命预测方法的可行性及有效性。后续可通过载荷数据的实测开展危险结构件的疲劳失效监测及寿命预测。

In order to study the fatigue characteristics of the components under random vibration loads, the random vibration fatigue tests for the metal structure parts are carried out by using a shaking table. The stress response load of the specimen during the test are measured with the retrofitted strain gauge, and the fatigue process of the specimen is monitored in a real-time way to obtain the fatigue life accurately. Based on the measured time-domain data, and by combining the rain flow counting method with the linear cumulative damage theory, the random vibration fatigue life of the specimens under three levels is predicted. The estimated values are well within the three-fold dispersion band compared with the experimental values, which verifies the feasibility and the effectiveness of the random vibration fatigue life prediction method based on the measured time-domain data. With the method, the fatigue failure monitoring and the life prediction for structural parts in the dangerous state can be carried out through the measurement of load data.