轴对称构件疲劳损伤演化方程与寿命预估方法的改进  

Improvement of Damage Evolution Equation and Method for Fatigue Life Prediction of Axial-Symmetrical Specimens

作　　者：张淼[1] 袁锋[1] 孟庆春[1] 张行[1] 

机构地区：[1]北京航空航天大学,北京100191

出　　处：《应用力学学报》2008年第3期489-493,共5页Chinese Journal of Applied Mechanics

摘　　要：以热力学为基础,引入损伤驱动力构建分式形式的损伤演化方程。进一步针对轴对称问题,引入等效应变和等效应力。根据损伤力学守恒积分原理,得到有损伤情况下和无损伤情况下应力应变与伤度的关系。利用分离变量方法再对损伤演化方程积分,得到棒试件在恒幅应变交变载荷作用下的应力与寿命关系的级数表达式。损伤演化方程中的材质参数由KT=1与KT=3的标准轴对称试件中值疲劳试验数据确定。损伤演化方程与寿命预估方法的正确性由KT=5的疲劳试验结果验证。利用级数解法对扩口管路连接件进行了寿命预估,提供了一种用损伤力学方法来描述构件的疲劳寿命可行的方法。Based on irreversible thermodynamics, damage evolution equation of fractional form is constructed by introducing damage driving force. The effective strain and effective stress are introduced under the condition of axial symmetry. By the theory of conservative integral, the strain with damage is expressed by the strain without damage and the damage extent for the case of small-scale damage. The integral of the damage evolution equation is obtained via variable separation, series of power function is derived to express the relation between the stress and the mean values of fatigue life under the repeated loading with constant amplitude. The material parameters in the damage evolution equation can be obtained by the mean values of experimental fatigue lives of axially symmetric specimens with KT=1 and KT=3. The correctness of the damage evolution equation and the method of fatigue life prediction can be checked by the mean values of experimental fatigue lives of axially symmetric specimens with KT=5. Fatigue life prediction of the flared type pipeline connection components is conducted.

关 键 词：损伤演化方程 寿命预估 轴对称 等效应力 守恒积分 

分 类 号：V215.5[航空宇航科学与技术—航空宇航推进理论与工程] V215.6