疲劳损伤问题中有效应力的一种定义

有效应力是损伤力学中的一个重要概念,这个概念的提出为用无损状态下的本构方程描述有损伤材料的行为提供了有效手段.本文探讨损伤力学中有效应力的定义,通过对损伤演化规律的分析,指出有效应力的一般定义不适用于疲劳损伤问题.本文认为,疲劳问题中的有效应力应该以等效寿命为基础,并根据剩余寿命的概念引入了疲劳损伤问题中有效应力的一种定义.

Discussion on Effective Stress in Fatigue Damage Problem

Presently, damage mechanics has be used successfully in plastic failure and creep damage process , and some damage mechanics models have also been introduced into fatigue study. Effective stress is one of the most important concept in damage mechanics, application of the concept of effective stress lays a foundation for discribing the mechanical behavior of damaged material by the constitutive equation of non-damaged material. The present paper disscussed the definition of effective stress in damage mechanics and its physical meaning, and through analysis from the physical pattern of damage and its evolution law, proposed such a definition is not suitable for fatigue damage problem. The authors think that the effective stress should be based on equivalent life in fatigue problem, thereby defined the concept of effective stress in fatigue damage according to the concept of remainder life.