摘要
抗震断裂问题是混凝土重力坝的重要研究内容,数值模拟则是针对此类问题的主要研究方法,现有断裂算法存在计算效率较低,大多未考虑接触等问题。为此,构造了高效的平均值坐标插值多边形单元和接触薄层单元,并将二者耦合后用于结构裂缝扩展的数值模拟。该方法将具有奇异特性以及复杂几何区域网格自适应性强的多边形有限元方法与平均值坐标插值方法、局部多边形网格策略结合起来模拟裂缝扩展;通过等参子三角形方法进行数值积分,求解刚度矩阵;基于最大周向应力准则,采用混合断裂强度因子作为起裂判据;针对裂缝面间的接触问题,引入张剪状态下的黏聚力模型以及压剪状态下的光滑接触模型。基于上述方法,通过Matlab编程的方式开发出一套能模拟裂缝扩展的程序,并通过对含边裂缝的PMMA板试验和含预设裂缝的四点剪切梁试验的模拟,验证了程序的准确性与有效性。最后,以含有预设裂缝的柯伊纳混凝土重力坝为例,对其在是否考虑接触问题下裂纹扩展的情况进行了对比分析,结果表明该程序模拟裂缝真实准确,具有计算速度快、结果文件小等独特优势。
Seismic fracture research is an important research content of concrete gravity dams.The numerical modeling is the main research method.Current fracture algorithms are inefficient and do not account the contact problems.In this paper,high efficiency polygonal finite element of mean value coordinate interpolation and contact thin layer element are constructed.The polygonal finite element method which is singularity and adapts well to complex geometries,is combined with the mean value coordinate interpolation method and the local polygonal mesh strategy to simulate the crack propagation.The stiffness matrix is solved by numerical integration using isoparametric sub-triangle method.Based on the maximum circumferential stress criterion,the hybrid fracture strength factor is employed as the crack initiation criteria.To address fracture surface contact,the cohesive force model in tension-shear and the smooth contact model in compression-shear are used.Based on the above methods,we use the Matlab to compile a program for simulating crack propagation.The program is validated by simulating PMMA plate tests with edge fractures and four-point shear beam tests with preset cracks.We present a comparative analysis of crack expansion with and without considering the contact problem for the Koyna concrete gravity dam in India,which has preset cracks.The conclusion is that the program has distinctive benefits such as realistic and accurate crack simulation,rapid calculating speed and small result files.
作者
徐强
董金凯
陈健云
李静
XU Qiang;DONG Jinkai;CHEN Jianyun;LI Jing(State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China;Institute of Earthquake Engineering,Dalian University of Technology,Dalian 116024,China)
出处
《人民长江》
北大核心
2023年第8期211-220,共10页
Yangtze River
基金
国家自然科学基金重大项目子课题“混凝土坝枢纽潜在失效模式与灾变机理研究”(52192672)。
关键词
混凝土重力坝
平均值坐标插值多边形有限元
裂缝扩展
接触算法
concrete gravity dam
polygon finite element of mean value coordinate interpolation
crack propagation
contact algorithm
