基于FE-EFG耦合算法的疲劳裂纹扩展数值模拟方法  

NUMERICAL SIMULATION METHOD FOR FATIGUE CRACK GROWTH BASED ON FE-FFG

作　　者：柳军[1,2] 张小洪[1] 刘清友[1] 何星[1] 黄陈[1] 

机构地区：[1]西南石油大学土木工程与建筑学院,成都610500 [2]西南石油大学机械工程博士后科研流动站,成都610500

出　　处：《机械强度》2013年第6期859-863,共5页Journal of Mechanical Strength

基　　金：国家自然科学基金项目(51105319);核反应堆系统设计技术国家级重点实验室基金;在役防喷器综合评价及专家系统开发项目资助~~

摘　　要：为了提高计算效率,提出采用一种新的数值模拟方法,耦合的有限元—无网格伽辽金方法(finite elementmeshfree Galerkin method,FE-EFG),计算含裂纹构件的位移场。在靠近裂纹尖端的区域采用EFG节点离散,在其他区域用有限元离散,充分利用两者的优势,避免各自的不足。根据获得的位移场,提出一种基于EFG方法的虚拟裂纹闭合法,用以计算应力强度因子。给出一种新的节点更新法用以模拟裂纹的扩展,用Paris法则确定裂纹扩展的速率。最终得到一种新的疲劳裂纹扩展数值模拟方法。数值算例表明,所提方法的计算结果与实验结果基本一致。In order to improve the computational efficiency, a new numerical method, coupled finite element-meshfree Galerkin method （FE-EFG） is proposed to calculate the displacement field of the cracked component. Noting the fact that element free Galerkin method （EFG） has remarkable advantage in simulating the fatigue crack growth, high computational precise and no grid renew request and has a obvious deficiency of low computational speed, EFG nodes is used to discrete the domain closed to the crack front and FE （ finite element） elements is used to model the remain part, in order to make use of the two method＇s merits and avoid their shortages. Based on the displacement field, a virtual crack closure technique based on EFG method is introduced to determine the stress intensity factor on the crack front. A new dynamic node renew method is proposed to discrete the numerical model in the simulation of crack growth, and Paris＇ law is used to determine the speed of the fatigue crack growth. A numerical example shows that the result of the numerical prediction method is reasonable agreement with experiments.

关 键 词：疲劳裂纹扩展 数值模拟方法 应力强度因子 耦合的FE-EFG方法 

分 类 号：TH123.3[机械工程—机械设计及理论]