双轴动载作用下脆性裂纹扩展问题的近场动力学建模与分析  

PERIDYNAMIC MODELLING AND ANALYSIS FOR CRACK PROPAGATION IN BRITTLE MATERIALS SUBJECTED TO BIAXIAL DYNAMIC LOAD

作　　者：牛彦泽 徐业鹏 黄丹[1] NIU Yan-ze;XU Ye-peng;HUANG Dan(College of Mechanics and Materials,Hohai University,Nanjing,Jiangsu,211100,China)

机构地区：[1]河海大学力学与材料学院,江苏南京211100

出　　处：《工程力学》2018年第10期249-256,共8页Engineering Mechanics

基　　金：国家自然科学基金项目(51679077;11132003);中央高校基本科研业务费项目(2015B18314;2017B13014);江苏省自然科学基金项目(BK20130822);NSFC-广东联合基金(第二期)超级计算科学应用研究专项项目(U1501501)

摘　　要：在双参数微极近场动力学弹脆性模型基础上,引入反映长程力尺寸效应的核函数修正项以提高定量计算精度和收敛稳定性。通过定量变形计算和双轴动载作用下含中心裂纹准脆性板的裂纹扩展过程模拟,验证了本文模型与算法。应用本文模型能准确反映动载作用下的裂纹起裂、扩展、分叉与二次分叉等现象。进一步分析了双轴动载作用下含不同倾角、不同间距平行双裂纹脆性板的破坏模式、起裂时间与承载能力,以及含不同倾角多裂纹脆性板的破坏机制。结果表明:初始裂纹倾角与间距对脆性板承载能力有显著影响,在平行双裂纹倾角一定时,间距越大脆性板承载能力越强;双轴动载作用下多裂纹扩展时,裂纹之间首先相互连接且无分叉,在初始裂纹连接贯通后向边界扩展时出现分叉及二次分叉。A kernel function reflecting the internal length effect of long-range forces has been introduced into a regular micropolar prototype elastic brittle peridynamic model,in order to improve the calculation accuracy and numerical stability of convergence.The proposed model and algorithms were validated through deformation calculation and simulation of crack propagation in a center-notched quasi-brittle plate subjected to a biaxial dynamic load.The crack initiation,propagation and branching can be described naturally by using the proposed approach.The failure mechanism as well as the influence of the direction and distance between two parallel cracks on the failure mode,cracking time,and the extreme failure load of a brittle plate subjected to biaxial dynamic loads have been analyzed further.Numerical results show that the directions of pre-existed cracks as well as the distance between cracks take an important effect on the failure mechanism of the plate.With given crack orientation,the plate shows higher loading capacity when the distance between two parallel pre-existed cracks increases.In the multiple-crack propagation process under biaxial dynamic loads,the pre-existed cracks connect to each other firstly without bifurcation,and then the converged cracks will bifurcate and re-branch when propagate to the boundary.

关 键 词：断裂力学 动力破坏 近场动力学 裂纹扩展 核函数 

分 类 号：O346.11[理学—固体力学]