具有不确定性的恒幅循环载荷疲劳可靠度异量纲干涉分析方法  

DISSIMILAR-DIMENSION INTERFERENCE MODEL OF FATIGUE RELIABILITY UNDER UNCERTAIN CYCLIC LOAD

作　　者：谢里阳[1] 王正[1] 

机构地区：[1]东北大学机械工程与自动化学院,沈阳110004

出　　处：《机械强度》2008年第5期763-767,共5页Journal of Mechanical Strength

基　　金：国家重大基础研究规划项目(973-2006CB605000);国家高技术项目(863探索导向课题-2006AA04Z408)资助~~

摘　　要：在概率统计平均的意义上重新解释传统的两个随机变量干涉分析的基本概念及模型,将干涉模型解释为载荷加权平均模型。具体地讲,是将应力—强度干涉模型解释、拓展为强度超越载荷概率的(载荷)统计加权平均模型,或作为应力水平函数的条件疲劳失效概率的载荷统计加权平均模型。这样,传统上只能应用于相同量纲随机变量(例如应力与强度,或载荷循环数与疲劳寿命)的干涉模型可以拓展应用于具有不同量纲随机变量(例如应力与寿命)的情形,即具有不确定性的循环载荷下的疲劳失效概率(寿命小于指定值的概率)或可靠度(寿命大于指定值的概率)计算。应用这样的模型,可以很方便地根据几个确定性恒幅循环载荷下的疲劳寿命分布预测具有不确定性的恒幅循环载荷作用下的疲劳失效概率或可靠度。文中还证明,先由寿命分布推导给定寿命下的疲劳强度分布,再根据应力—强度干涉模型计算可靠度的传统公式本质上与文中提出的统计平均模型是一致的。Traditional stress-strength interference model was reinterpreted as that to express the weighted statistical average of the probability that strength is greater than stress, or vice versa. Thus, the same model format, which traditionally can only be used for the situation of the parameters of the same unit （e.g., load and stress, both are measured by MPa; or load cycle and life, both are measured by number of load cycles）, can be applied to more general situation. In other words, the traditional model was extended to the situation of any two variables, as long as one of the variable can be expressed as a function of the other. By such a model, fatigue failure probability/reliability can be calculated with known load distribution and fatigue life distribution. Besides, it was verified that the conventional approach, in which fatigue strength under specific life cycles should be derived from fatigue life distribution, and then the stressstrength interference model is applied to calculate fatigue reliability, is essentially the same as the proposed statistical average model.

关 键 词：疲劳 可靠性 循环载荷 异量纲干涉模型 

分 类 号：O346.1[理学—固体力学] O346.2[理学—力学]