【摘要】 引入应力集中因子修正疲劳极限,提出一种实用有效的损伤演化方程。根据损伤力学守恒积分原理,得到缺口试件应力和应变集中与损伤度的耦合关系。利用分离变量方法对损伤演化方程积分,得到构件的应力与寿命关系的积分表达式。损伤演化方程中的材质参数由KT=1与KT=3的标准板试件试验疲劳曲线确定。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,为采用损伤力学方法预估构件的疲劳寿命提供一种可行的方法。最后,应用此方法提供KT=4与KT=2时的理论疲劳曲线。更多还原

【Abstract】 The stress concentration factor is introduced to modify the fatigue limit and a practical damage evolution equation is established.According to the theory of conservative integral in damage mechanics,the damage coupling effect of stress and strain concentration in notched specimen can be expressed in closed form solution.Then,integrating the damage evolution equation by means of variable separation method,an integral expression of stresslife relation can be established.The material parameters of damage evolution equation are obtained by fatigue curves of standard plane specimens with KT=1 and KT=3.The correctness of damage evolution equation and the fatigue life prediction method are verified through the results of fatigue experiment with KT= 5.Hence a practical method to predict the fatigue life of structures can be provided by using damage mechanics.Finally,this method is applied to provide the theoretical fatigue curves for KT = 4 and KT=2.更多还原