插值型无单元Galerkin比例边界法是一种只需在边界上采用插值型无单元Galerkin法离散且无需基本解的半解析方法,能有效求解压电材料的断裂问题.为进一歩提高这种方法的适用性,该文提出了一种用于压电材料断裂分析的插值型无单元Galerki...插值型无单元Galerkin比例边界法是一种只需在边界上采用插值型无单元Galerkin法离散且无需基本解的半解析方法,能有效求解压电材料的断裂问题.为进一歩提高这种方法的适用性,该文提出了一种用于压电材料断裂分析的插值型无单元Galerkin比例边界法耦合有限元法(finite element method,FEM)的分析方法.裂纹周边一定范围的计算域采用插值型无单元Galerkin比例边界法离散,其余区域采用FEM离散.插值型无单元Galerkin比例边界法方程和FEM方程的耦合可利用界面两侧广义位移的连续条件方便地实现.最后,给出了两个数值算例验证了该文所提方法的有效性.展开更多
高阶双渐近时域透射边界能够同时模拟行波和快衰波的传播,并且能够在全频范围内迅速逼近准确解,具有优良的收敛性能和计算效率.本文将动水压力波高阶双渐近透射边界直接嵌入到近场有限元方程中,建立了大坝-库水动力相互作用的直接耦合...高阶双渐近时域透射边界能够同时模拟行波和快衰波的传播,并且能够在全频范围内迅速逼近准确解,具有优良的收敛性能和计算效率.本文将动水压力波高阶双渐近透射边界直接嵌入到近场有限元方程中,建立了大坝-库水动力相互作用的直接耦合分析模型.该模型的整体控制方程保留了近场有限元方程系数矩阵对称稀疏的优势,可以方便地利用现有的通用有限元求解器求解.基于有限元开源软件框架体系OpenSees(Open System for Earthquake Engineering Simulation),编程实现了直接耦合分析模型,并将其应用于二维重力坝、三维拱坝与库水动力相互作用分析.数值算例表明,该直接耦合分析模型具有很高的精度和计算效率.展开更多
The prediction of dynamic crack propagation in brittle materials is still an important issue in many engineering fields. The remeshing technique based on scaled boundary finite element method(SBFEM) is extended to pre...The prediction of dynamic crack propagation in brittle materials is still an important issue in many engineering fields. The remeshing technique based on scaled boundary finite element method(SBFEM) is extended to predict the dynamic crack propagation in brittle materials. The structure is firstly divided into a number of superelements, only the boundaries of which need to be discretized with line elements. In the SBFEM formulation, the stiffness and mass matrices of the super-elements can be coupled seamlessly with standard finite elements, thus the advantages of versatility and flexibility of the FEM are well maintained. The transient response of the structure can be calculated directly in the time domain using a standard time-integration scheme. Then the dynamic stress intensity factor(DSIF) during crack propagation can be solved analytically due to the semi-analytical nature of SBFEM. Only the fine mesh discretization for the crack-tip super-element is needed to ensure the required accuracy for the determination of stress intensity factor(SIF). According to the predicted crack-tip position, a simple remeshing algorithm with the minimum mesh changes is suggested to simulate the dynamic crack propagation. Numerical examples indicate that the proposed method can be effectively used to deal with the dynamic crack propagation in a finite sized rectangular plate including a central crack. Comparison is made with the results available in the literature, which shows good agreement between each other.展开更多
文摘插值型无单元Galerkin比例边界法是一种只需在边界上采用插值型无单元Galerkin法离散且无需基本解的半解析方法,能有效求解压电材料的断裂问题.为进一歩提高这种方法的适用性,该文提出了一种用于压电材料断裂分析的插值型无单元Galerkin比例边界法耦合有限元法(finite element method,FEM)的分析方法.裂纹周边一定范围的计算域采用插值型无单元Galerkin比例边界法离散,其余区域采用FEM离散.插值型无单元Galerkin比例边界法方程和FEM方程的耦合可利用界面两侧广义位移的连续条件方便地实现.最后,给出了两个数值算例验证了该文所提方法的有效性.
文摘高阶双渐近时域透射边界能够同时模拟行波和快衰波的传播,并且能够在全频范围内迅速逼近准确解,具有优良的收敛性能和计算效率.本文将动水压力波高阶双渐近透射边界直接嵌入到近场有限元方程中,建立了大坝-库水动力相互作用的直接耦合分析模型.该模型的整体控制方程保留了近场有限元方程系数矩阵对称稀疏的优势,可以方便地利用现有的通用有限元求解器求解.基于有限元开源软件框架体系OpenSees(Open System for Earthquake Engineering Simulation),编程实现了直接耦合分析模型,并将其应用于二维重力坝、三维拱坝与库水动力相互作用分析.数值算例表明,该直接耦合分析模型具有很高的精度和计算效率.
基金Supported by the Key Program of National Natural Science Foundation of China(No.51138001)the Science Fund for Creative Research Groups of National Natural Science Foundation of China(No.51121005)+2 种基金the Fundamental Research Funds for the Central Universities(DUT13LK16)the Young Scientists Fund of National Natural Science Foundation of China(No.51109134)China Postdoctoral Science Foundation(No.2011M500814)
文摘The prediction of dynamic crack propagation in brittle materials is still an important issue in many engineering fields. The remeshing technique based on scaled boundary finite element method(SBFEM) is extended to predict the dynamic crack propagation in brittle materials. The structure is firstly divided into a number of superelements, only the boundaries of which need to be discretized with line elements. In the SBFEM formulation, the stiffness and mass matrices of the super-elements can be coupled seamlessly with standard finite elements, thus the advantages of versatility and flexibility of the FEM are well maintained. The transient response of the structure can be calculated directly in the time domain using a standard time-integration scheme. Then the dynamic stress intensity factor(DSIF) during crack propagation can be solved analytically due to the semi-analytical nature of SBFEM. Only the fine mesh discretization for the crack-tip super-element is needed to ensure the required accuracy for the determination of stress intensity factor(SIF). According to the predicted crack-tip position, a simple remeshing algorithm with the minimum mesh changes is suggested to simulate the dynamic crack propagation. Numerical examples indicate that the proposed method can be effectively used to deal with the dynamic crack propagation in a finite sized rectangular plate including a central crack. Comparison is made with the results available in the literature, which shows good agreement between each other.
