摘要
为了研究TB5钛合金板试件从微观初始缺陷到宏观疲劳断裂全过程中的跨尺度数值模拟问题,以约束应力表征材料的疲劳损伤度,以约束应力区裂纹模型描述材料从微观到宏观的疲劳破坏过程,以应变能密度因子作为宏微观跨尺度疲劳裂纹扩张的控制参量,发展了一种宏微观跨尺度疲劳破坏过程的数值模拟方法。在该模型中,可通过疲劳源处材料初始缺陷大小和3个尺度效应函数来表征材料微观因素对疲劳破坏过程的影响。对TB5钛合金光滑板试件(应力集中系数Kt=1)和含切口板试件(Kt=3)进行了数值模拟计算,结果表明,计算S-N曲线与试验S-N曲线能够精准吻合。通过考虑微观效应,其疲劳寿命试验数据的离散性也可由模型计算结果得以体现。
The numerical simulation for the trans-scale fatigue failure process of TB5 titanium alloy plate specimens from the initial micro-defect to the macroscopic fatigue fracture is investigated.The fatigue damage degree can be represented by the restraining stresses.The micro/macro fatigue failure process can be described by the restraining stress zone crack model.Taking the micro/macro trans-scale strain energy density factor as a controlling parameter for the fatigue crack propagation,a micro/macro trans-scale numerical simulation approach for the fatigue process is developed.Adopting three scaling functions and the size of initial micro-defects at the fatigue source position,the influence of microscopic effects on the fatigue lives of specimens can be taken into account.The numerical simulation calculations are performed for the TB5 titanium alloy smooth plate specimens(stress concentration factor Kt=1)and the notched plate specimens(Kt=3).The results show that the calculated S-N curves can accurately fit the experimental S-N curves.With consideration of the microscopic effects,the scattered test data of fatigue lives of specimens can be re-produced by the proposed approach.
作者
唐雪松
刘唐
彭旭龙
TANG Xue-song;LIU Tang;PENG Xu-long(School of Civil Engineering,Changsha University of Science and Technology,Changsha 410114,China)
出处
《长沙理工大学学报（自然科学版）》
CAS
2019年第1期73-78,共6页
Journal of Changsha University of Science and Technology:Natural Science
基金
国家重点基础研究发展计划(973计划)项目(2015CB057705)
关键词
断裂力学
钛合金
S-N曲线
疲劳裂纹扩张
宏微观跨尺度分析
微观效应
fracture mechanics
titanium alloy
S-N curve
fatigue crack growth
micro/macro trans-scale analysis
microscopic effect
