Using the complex variable method and conformal mapping,scat- tering of flexural waves and dynamic stress concentrations in Mindlin's thick plates with a cutout have been studied.The general solution of the stress...Using the complex variable method and conformal mapping,scat- tering of flexural waves and dynamic stress concentrations in Mindlin's thick plates with a cutout have been studied.The general solution of the stress problem of the thick plate satisfying the boundary conditions on the contour of cutouts is obtained. Applying the orthogonal function expansion technique,the dynamic stress problem can be reduced into the solution of a set of infinite algebraic equations.As examples, numerical results for the dynamic stress concentration factor in Mindlin's plates with a circular,elliptic cutout are graphically presented in sequence.展开更多
The numerical investigation of regular waves interacting with a submerged horizontal twin-plate breakwater is pre- sented in this paper. A numerical model with an absorbing wave-maker is established based on the VOF m...The numerical investigation of regular waves interacting with a submerged horizontal twin-plate breakwater is pre- sented in this paper. A numerical model with an absorbing wave-maker is established based on the VOF method. The validity of the model is verified by experimental results. Comparisons between the numerical and experimental results show that beth the water surface profiles and the wave-induced pressures can be modeled accurately. Wave deformation over the breakwater, water particle velocities around the breakwater, and the wave-induced pressures on the structure are nu- merically investigated. Tile pressure amplitudes of the fundamental and second harmonies on the model surface are exanl- ined in various water depths. The computed and experimental results have revealed that the higher frequency components are generated at the onshore side of the breakwater. Furthermore, the computed results demonstrate a circulating flow formed at the onshore side of the breakwater.展开更多
The bending of rectangular plate is divided into the generalized statically determinate bending and the generalized statically indeterminate bending based on the analysis of the completeness of calculating condition a...The bending of rectangular plate is divided into the generalized statically determinate bending and the generalized statically indeterminate bending based on the analysis of the completeness of calculating condition at the corner point. The former can be solved directly by the equilibrium differential equation and the boundary conditions of four edges of the plate. The latter can be solved by using the superposition principle. Making use of the recommended method, the bending of the plate with all kinds of...展开更多
The purpose of the present work is to study the buckling problem with plate/shell topology optimization of orthotropic material. A model of buckling topology optimization is established based on the independent, conti...The purpose of the present work is to study the buckling problem with plate/shell topology optimization of orthotropic material. A model of buckling topology optimization is established based on the independent, continuous, and mapping method, which considers structural mass as objective and buckling critical loads as constraints. Firstly, composite exponential function (CEF) and power function (PF) as filter functions are introduced to recognize the element mass, the element stiffness matrix, and the element geometric stiffness matrix. The filter functions of the orthotropic material stiffness are deduced. Then these filter functions are put into buckling topology optimization of a differential equation to analyze the design sensitivity. Furthermore, the buckling constraints are approximately expressed as explicit functions with respect to the design variables based on the first-order Taylor expansion. The objective function is standardized based on the second-order Taylor expansion. Therefore, the optimization model is translated into a quadratic program. Finally, the dual sequence quadratic programming (DSQP) algorithm and the global convergence method of moving asymptotes algorithm with two different filter functions (CEF and PF) are applied to solve the optimal model. Three numerical results show that DSQP&CEF has the best performance in the view of structural mass and discretion.展开更多
In this work, the finite element analysis of the elasto-plastic plate bending problems is carried out using transition rectangular plate elements. The shape functions of the transition plate elements are derived based...In this work, the finite element analysis of the elasto-plastic plate bending problems is carried out using transition rectangular plate elements. The shape functions of the transition plate elements are derived based on a practical rule. The transition plate elements are all quadrilateral and can be used to obtain efficient finite element models using minimum number of elements. The mesh convergence rates of the models including the transition elements are compared with the regular element models. To verify the developed elements, simple tests are demonstrated and various elasto-plastic problems are solved. Their results are compared with ANSYS results.展开更多
板结构与其他构件的装配关系可用不同的边界条件进行模拟,然而针对不同边界条件的板结构进行动力学特性分析,目前缺乏统一的数学建模方法。以混合弹性边界条件下加筋、开孔的板类结构的横向振动为例,利用Rayleigh-Ritz法和模态叠加法求...板结构与其他构件的装配关系可用不同的边界条件进行模拟,然而针对不同边界条件的板结构进行动力学特性分析,目前缺乏统一的数学建模方法。以混合弹性边界条件下加筋、开孔的板类结构的横向振动为例,利用Rayleigh-Ritz法和模态叠加法求解矩形加筋多孔板在简谐激励下的动力学响应问题。采用将开孔板与加强筋沿交界面进行分离,结合改进的傅里叶级数设定开孔板的横向振动位移函数,利用不同刚度弹簧模拟混合弹性边界,推导加筋矩形开多孔板和边界弹簧系统的动能与势能,求解其在简谐激励下的动力学响应。经对比,理论计算结果与有限元(Finite Element Method,FEM)结果吻合良好。此外,用同样的方法分析不同孔尺寸对结构固有频率和响应的影响。研究发现,可通过改变加筋板的开孔形状、尺寸对结构的振动特性进行调整。研究成果可为混合弹性边界板结构动力分析提供一种新的技术途径,可以简化加筋开孔板结构动力分析的步骤。展开更多
The convergence of interpolated-iterative method, which is applied to solve von Karman ’sequations of circular plates, has been strictly proved for unilateral arbitrary loads. On thebasis of programme of selecting in...The convergence of interpolated-iterative method, which is applied to solve von Karman ’sequations of circular plates, has been strictly proved for unilateral arbitrary loads. On thebasis of programme of selecting interpolated-iterative parameters, the strong nonlinearbending solutions of thin plates can be obtained exactly.展开更多
When a body consists completely or even partly of viscoelastic materials, its response under static loading will be time-dependent. The adhesives used to glue together single plies in laminates usually exhibit a certa...When a body consists completely or even partly of viscoelastic materials, its response under static loading will be time-dependent. The adhesives used to glue together single plies in laminates usually exhibit a certain viscoelastic characteristic in a high temperature environment. In this paper, a laminated orthotropic rectangular plate with viscoelastic interfaces, described by the Kelvin-Voigt model, is considered. A power series expansion technique is adopted to approximate the time-variation of various field quantities. Results indicate that the response of the laminated plate with viscoelastic interfaces changes remarkably with time, and is much different from that of a plate with spring-like or viscous interfaces.展开更多
基金The project supported by the National Natural Science Foundation of China
文摘Using the complex variable method and conformal mapping,scat- tering of flexural waves and dynamic stress concentrations in Mindlin's thick plates with a cutout have been studied.The general solution of the stress problem of the thick plate satisfying the boundary conditions on the contour of cutouts is obtained. Applying the orthogonal function expansion technique,the dynamic stress problem can be reduced into the solution of a set of infinite algebraic equations.As examples, numerical results for the dynamic stress concentration factor in Mindlin's plates with a circular,elliptic cutout are graphically presented in sequence.
基金supported by the National Natural Science Foundation of China ( Grant Nos .50921001 and 51079025)
文摘The numerical investigation of regular waves interacting with a submerged horizontal twin-plate breakwater is pre- sented in this paper. A numerical model with an absorbing wave-maker is established based on the VOF method. The validity of the model is verified by experimental results. Comparisons between the numerical and experimental results show that beth the water surface profiles and the wave-induced pressures can be modeled accurately. Wave deformation over the breakwater, water particle velocities around the breakwater, and the wave-induced pressures on the structure are nu- merically investigated. Tile pressure amplitudes of the fundamental and second harmonies on the model surface are exanl- ined in various water depths. The computed and experimental results have revealed that the higher frequency components are generated at the onshore side of the breakwater. Furthermore, the computed results demonstrate a circulating flow formed at the onshore side of the breakwater.
文摘The bending of rectangular plate is divided into the generalized statically determinate bending and the generalized statically indeterminate bending based on the analysis of the completeness of calculating condition at the corner point. The former can be solved directly by the equilibrium differential equation and the boundary conditions of four edges of the plate. The latter can be solved by using the superposition principle. Making use of the recommended method, the bending of the plate with all kinds of...
基金supported by the National Natural Science Foundation of China (Grants 11072009, 11172013)the Beijing Education Committee Development Project (Grant SQKM2016100 05001)the Beijing University of Technology Basic Research Fund (Grant 001000514313003)
文摘The purpose of the present work is to study the buckling problem with plate/shell topology optimization of orthotropic material. A model of buckling topology optimization is established based on the independent, continuous, and mapping method, which considers structural mass as objective and buckling critical loads as constraints. Firstly, composite exponential function (CEF) and power function (PF) as filter functions are introduced to recognize the element mass, the element stiffness matrix, and the element geometric stiffness matrix. The filter functions of the orthotropic material stiffness are deduced. Then these filter functions are put into buckling topology optimization of a differential equation to analyze the design sensitivity. Furthermore, the buckling constraints are approximately expressed as explicit functions with respect to the design variables based on the first-order Taylor expansion. The objective function is standardized based on the second-order Taylor expansion. Therefore, the optimization model is translated into a quadratic program. Finally, the dual sequence quadratic programming (DSQP) algorithm and the global convergence method of moving asymptotes algorithm with two different filter functions (CEF and PF) are applied to solve the optimal model. Three numerical results show that DSQP&CEF has the best performance in the view of structural mass and discretion.
文摘In this work, the finite element analysis of the elasto-plastic plate bending problems is carried out using transition rectangular plate elements. The shape functions of the transition plate elements are derived based on a practical rule. The transition plate elements are all quadrilateral and can be used to obtain efficient finite element models using minimum number of elements. The mesh convergence rates of the models including the transition elements are compared with the regular element models. To verify the developed elements, simple tests are demonstrated and various elasto-plastic problems are solved. Their results are compared with ANSYS results.
文摘板结构与其他构件的装配关系可用不同的边界条件进行模拟,然而针对不同边界条件的板结构进行动力学特性分析,目前缺乏统一的数学建模方法。以混合弹性边界条件下加筋、开孔的板类结构的横向振动为例,利用Rayleigh-Ritz法和模态叠加法求解矩形加筋多孔板在简谐激励下的动力学响应问题。采用将开孔板与加强筋沿交界面进行分离,结合改进的傅里叶级数设定开孔板的横向振动位移函数,利用不同刚度弹簧模拟混合弹性边界,推导加筋矩形开多孔板和边界弹簧系统的动能与势能,求解其在简谐激励下的动力学响应。经对比,理论计算结果与有限元(Finite Element Method,FEM)结果吻合良好。此外,用同样的方法分析不同孔尺寸对结构固有频率和响应的影响。研究发现,可通过改变加筋板的开孔形状、尺寸对结构的振动特性进行调整。研究成果可为混合弹性边界板结构动力分析提供一种新的技术途径,可以简化加筋开孔板结构动力分析的步骤。
基金Project supported by the National Natural Science Foundation of China.
文摘The convergence of interpolated-iterative method, which is applied to solve von Karman ’sequations of circular plates, has been strictly proved for unilateral arbitrary loads. On thebasis of programme of selecting interpolated-iterative parameters, the strong nonlinearbending solutions of thin plates can be obtained exactly.
基金Project supported by the National Natural Science Foundation of China (No. 10432030) and NCET.
文摘When a body consists completely or even partly of viscoelastic materials, its response under static loading will be time-dependent. The adhesives used to glue together single plies in laminates usually exhibit a certain viscoelastic characteristic in a high temperature environment. In this paper, a laminated orthotropic rectangular plate with viscoelastic interfaces, described by the Kelvin-Voigt model, is considered. A power series expansion technique is adopted to approximate the time-variation of various field quantities. Results indicate that the response of the laminated plate with viscoelastic interfaces changes remarkably with time, and is much different from that of a plate with spring-like or viscous interfaces.
