基于灰色系统理论的7075铝合金板材疲劳寿命研究

Study on fatigue life of aluminum alloy 7075 sheet based on grey system theory

在航空用飞机蒙皮制造过程中,7075铝合金是十分理想的材料。为了更精确地研究并预测7075铝合金的疲劳寿命,对7075-T-651铝合金板材进行了疲劳试验,在应力比R=0.1条件下,测得120~320 MPa不同应力下7075-T-651铝合金板材的疲劳寿命。以试验数据为基础,将灰色系统理论运用到7075-T-651铝合金板材的疲劳寿命预测中,生成GM(1,1)模型,在与试验相同的条件下进行疲劳寿命预测,并将得到的疲劳寿命预测模型S-N曲线与试验数据S-N曲线进行对比。研究表明,所建立的灰色系统理论GM(1,1)模型S-N曲线与试验所得S-N曲线基本吻合,因此,可以通过GM(1,1)模型来预测7075铝合金板材的疲劳寿命。

In the manufacturing of aeroplane skin for aviation,aluminum alloy 7075 is a kind of ideal material.In order to predict the fatigue life of aluminum alloy 7075 precisely,several fatigue experiments were conducted.Under the condition of stress ratio R = 0.1,the fatigue lives of aluminum alloy 7075-T-651 sheet were measured with different stresses of 120-320 MPa.Then,based on the experiment results,the grey system theory was used in the fatigue life prediction of aluminum alloy 7075-T-651 sheet,and the GM（1,1）model was generated.At the same time,the fatigue life prediction was conducted at the same conditions as the experiment,and the S-N curves of the prediction model and the experimental data were compared.This research shows that the S-N curve of the prediction model is the same as that of experiment.Thus,the GM（1,1） model can predict the fatigue life of aluminum alloy 7075.