疲劳寿命估算的线性累积破坏率准则研究

Research on linear cumulative failure probability rule about fatigue life estimation

摘要:

介绍了一种新的疲劳寿命估算方法——线性累积破坏率准则,其物理意义明确,简单明了。在对恒幅载荷疲劳寿命统计分析的基础上,求出对应的疲劳寿命概率密度函数,从而利用线性累积破坏率准则可估算出变幅载荷下结构的疲劳寿命。线性累积破坏率准则没有限定试验条件和疲劳寿命分布形式,因此对一般环境下和腐蚀环境下的疲劳均具适用性。利用两组疲劳试验数据对该方法进行了验证,结果表明在中值寿命附近预测寿命与实测寿命非常接近,精度较高、有较好的工程应用价值。

Abstract:

A new estimating method of fatigue life—linear cumulative failure probability rule is put forward. This rule is specific and simple in physics meaning and calculating. On the basis of the statistic analysis about constant amplitude fatigue lives, the probability density functions of fatigue life are deduced accordingly and then the fatigue life under varying amplitude loading is predicted by the rule. Test conditions and distributions of the fatigue life are not limited, therefore it can be used properly to estimate fatigue lives under general and corrosive environments. The rule is verified through two sets of fatigue test results. It showed that the estimating median life is close to the measuring life, and the rule is more accurately. The method is useful in engineering application.