【摘要】 引入描述双变量损伤条件下的本构关系,进而以热力学原理为基础,引入损伤驱动力,建立损伤演化准则。构建一般情况下的时间型损伤演化方程和循环型损伤演化方程。利用分离变量方法再对损伤演化方程积分,得到光滑试件在恒幅应变交变载荷作用下寿命预估方法。根据损伤力学守恒积分原理,得到有缺口试件在恒幅应变交变载荷作用下寿命预估方法。利用上述寿命预估方法,由KT=1与KT=3的标准试件中值疲劳试验数据确定损伤演化方程中的材质参数。在此基础上给出不同KT下的理论中值疲劳曲线,为采用损伤力学方法来描述构件的疲劳寿命提供一种可行的方法。更多还原

【Abstract】 Constitutive relation of bi-variable damage was introduced.Based on irreversible thermodynamics,damage driving force was introduced and damage evolution criterion was constructed.Furthermore,damage evolution equation of time form and cycle form was constructed.The fatigue life prediction method for smooth specimen under the repeated loading with constant strain amplitude was obtained by the method of variables separation.By the theory of conservative integral in damage mechanics,the fatigue life prediction method for notched specimen under the repeated loading with constant amplitude was obtained by numerical method.Using these methods,the material parameters in the damage evolution equation are obtained by the mean value experimental fatigue lives of standard specimens with KT = 1 and KT = 3.On the basis of above methods,theoritical mean fatigue curves for different values of KT are drawn.This research provides the possibility for predicting the fatigue lives of structure members through the methodology of damage mechanics.更多还原