含埋藏裂纹结构的拘束效应和蠕变裂纹孕育期研究  

ANALYSIS OF THE CONSTRAINT EFFECT AND CREEP CRACK INITIATION TIME FOR STRUCTURE WITH EMBEDDED CRACKS

作　　者：李宇鹏 李文彭 李顶河 邬栋权 王宇峰 郑宇翔 LI YuPeng;LI WenPeng;LI DingHe;WU DongQuan;WANG YuFeng;ZHENG YuXiang(Sino-European Institute of Aviation Engineering,Civil Aviation University of China,Tianjin 300300,China)

机构地区：[1]中国民航大学中欧航空工程师学院,天津300300

出　　处：《机械强度》2024年第2期461-467,共7页Journal of Mechanical Strength

基　　金：天津市教委科研计划项目(2021KJ053);中央高校基本科研业务费项目(3122021083);大学生创新训练计划项目(202110059135)资助。

摘　　要：以含埋藏椭圆形裂纹的高温试样结构为研究对象,基于延性耗散模型,用三维(3D)有限元方法对其拘束效应和蠕变裂纹孕育期进行了研究。结果表明,对于裂尖前沿拘束水平,拘束参量Q的最大值总是分布在椭圆形裂纹的长轴端点处,且随着裂纹横向长度c和纵向长度a的增加,拘束参量Q越大,意味着应力集中越严重,该处位置更为危险;对于蠕变裂纹孕育期,椭圆形裂纹深度比a/t越大或长度比a/c越小,或者载荷越大,则蠕变裂纹损伤率越高,结构发生蠕变裂纹萌生的孕育期越短,结构越危险。此外,建立了拘束参量和蠕变裂纹孕育期的预测公式和工程计算方法,并验证了蠕变裂纹孕育期工程计算模型的有效性。The specimen structure with embedded cracks served at elevated temperature was studied.The constraint effect and creep crack initiation time were analysed using the ductility exhaustion approach by 3D finite element method.The results revealed that the max value of constraint parameter was located at the end of major axis of elliptical crack,and the constraint levels enlarge with increasing the crack length or the crack depth,which meant that embedded cracks with a larger a/t or a/c would suffer from worse condition of stress concentration and there would be more dangerous.Besides,for the creep crack initiation times,the structure with a larger a/t or a/c or loadings would accompany high crack driving force under creep condition,which could cause a shorter period to creep cracking initiation,as well as a smaller creep crack initiation time.Additionally,a prediction equation and engineering method of the constraint parameters and creep crack initiation time for embedded cracks was proposed,and the prediction method of creep crack initiation time was validated.

关 键 词：埋藏裂纹 蠕变孕育期 延性耗散模型 蠕变损伤 拘束效应 

分 类 号：TK225[动力工程及工程热物理—动力机械及工程]