For many years finite element method(FEM)was the chosen numerical method for the analysis of composite structures.However,in the last 20 years,the scientific community has witnessed the birth and development of severa...For many years finite element method(FEM)was the chosen numerical method for the analysis of composite structures.However,in the last 20 years,the scientific community has witnessed the birth and development of several meshless methods,which are more flexible and equally accurate numerical methods.The meshless method used in this work is the natural neighbour radial point interpolation method(NNRPIM).In order to discretize the problem domain,the NNRPIM only requires an unstructured nodal distribution.Then,using the Voronoi mathematical concept,it enforces the nodal connectivity and constructs the background integration mesh.The NNRPIM shape functions are constructed using the radial point interpolation technique.In this work,the displacement field of composite laminated plates is defined by high-order shear deformation theories.In the end,several antisymmetric cross-ply laminates were analysed and the NNRPIM solutions were compared with the literature.The obtained results show the efficiency and accuracy of the NNRPIM formulation.展开更多
This paper presents an efficient and automated Overset Grid Assembly(OGA)method for the structured grid,and investigates high-order interpolation methods for inter-grid boundaries with the cell-centered finite differe...This paper presents an efficient and automated Overset Grid Assembly(OGA)method for the structured grid,and investigates high-order interpolation methods for inter-grid boundaries with the cell-centered finite difference method.Four enhancements are introduced:a hybrid holecutting approach integrates the efficiency of approximate hole-cutting and the accuracy and robustness of direct-cutting,effectively addressing challenges such as small gaps and thin cuts;an improved implicit hole boundary optimization method,incorporating quality comparison,can significantly reduce donor search workloads;an improved implicit interpolation cell cancellation algorithm minimizes overlap regions,particularly beneficial for high-order interpolation with large stencils;an algorithm for identifying and eliminating islands without using wall distances,effectively removes islands.The OGA results of a multi-element airfoil,a circular array of cylinders,multiple spheres,and a wing-pylon-store configuration indicate that the proposed method would be a suitable selection for multi-body problems,even in the presence of small gaps and thin geometries.Additionally,for high-order interpolation at inter-grid boundaries,this study presents an optimized interpolation method designed to minimize spectral property errors.Numerical results indicate that for periodic problems frequently crossing inter-grid boundaries,the optimized interpolation is more accurate than classical Lagrange interpolation and would be a suitable selection.展开更多
Advancing electron beam applications require pushing toward the quantum degeneracy limit.Nanoscale structured cathodes are a promising electron source for this regime,but the numerical tools for studying these designs...Advancing electron beam applications require pushing toward the quantum degeneracy limit.Nanoscale structured cathodes are a promising electron source for this regime,but the numerical tools for studying these designs remain limited.A previous paper detailed the implemented of a flat-panel fast-multipole-accelerated boundary element method,which solves the relevant Poisson problem.However,flat panels are inadequate and inefficient for representing curved surfaces at the high precision necessary for many applications.Additionally,the boundary element method has an established numerical instability when evaluated near the domain boundary.To resolve this,a general high-order curvilinear element interpolation and modified quadrature method is developed utilizing a differential algebraic mapping for greater accuracy in the boundary surface representation.The boundary instability effect is mitigated by devising local corrections to the quadrature scheme in the form of Cartesian Taylor expansions.This approach is suitably general,requiring only small modifications for application to other kernels,and can easily be incorporated into a fast multipole accelerated framework.The refined algorithm is evaluated with respect to both accuracy and efficiency using several analytic structures and the performance capacity is highlighted by the capability of accurately determining the field enhancement factor for a single nanotip electron cathode.展开更多
文摘For many years finite element method(FEM)was the chosen numerical method for the analysis of composite structures.However,in the last 20 years,the scientific community has witnessed the birth and development of several meshless methods,which are more flexible and equally accurate numerical methods.The meshless method used in this work is the natural neighbour radial point interpolation method(NNRPIM).In order to discretize the problem domain,the NNRPIM only requires an unstructured nodal distribution.Then,using the Voronoi mathematical concept,it enforces the nodal connectivity and constructs the background integration mesh.The NNRPIM shape functions are constructed using the radial point interpolation technique.In this work,the displacement field of composite laminated plates is defined by high-order shear deformation theories.In the end,several antisymmetric cross-ply laminates were analysed and the NNRPIM solutions were compared with the literature.The obtained results show the efficiency and accuracy of the NNRPIM formulation.
基金supported by the Foundation of State Key Laboratory of Aerodynamics of China(No.SKLA-2024-KFKT-1-008)the National Natural Science Foundation of China(No.91952203)。
文摘This paper presents an efficient and automated Overset Grid Assembly(OGA)method for the structured grid,and investigates high-order interpolation methods for inter-grid boundaries with the cell-centered finite difference method.Four enhancements are introduced:a hybrid holecutting approach integrates the efficiency of approximate hole-cutting and the accuracy and robustness of direct-cutting,effectively addressing challenges such as small gaps and thin cuts;an improved implicit hole boundary optimization method,incorporating quality comparison,can significantly reduce donor search workloads;an improved implicit interpolation cell cancellation algorithm minimizes overlap regions,particularly beneficial for high-order interpolation with large stencils;an algorithm for identifying and eliminating islands without using wall distances,effectively removes islands.The OGA results of a multi-element airfoil,a circular array of cylinders,multiple spheres,and a wing-pylon-store configuration indicate that the proposed method would be a suitable selection for multi-body problems,even in the presence of small gaps and thin geometries.Additionally,for high-order interpolation at inter-grid boundaries,this study presents an optimized interpolation method designed to minimize spectral property errors.Numerical results indicate that for periodic problems frequently crossing inter-grid boundaries,the optimized interpolation is more accurate than classical Lagrange interpolation and would be a suitable selection.
基金supported in part by the U.S.Department of Energy,Office of High Energy Physics,under Contract No.DE-SC0011831 and DE-SC002024by the National Science Foundation(NSF)under Grant PHY-1535401 with Northern Illinois Universitythe Center for Research Computing and Data at Northern Illinois University.
文摘Advancing electron beam applications require pushing toward the quantum degeneracy limit.Nanoscale structured cathodes are a promising electron source for this regime,but the numerical tools for studying these designs remain limited.A previous paper detailed the implemented of a flat-panel fast-multipole-accelerated boundary element method,which solves the relevant Poisson problem.However,flat panels are inadequate and inefficient for representing curved surfaces at the high precision necessary for many applications.Additionally,the boundary element method has an established numerical instability when evaluated near the domain boundary.To resolve this,a general high-order curvilinear element interpolation and modified quadrature method is developed utilizing a differential algebraic mapping for greater accuracy in the boundary surface representation.The boundary instability effect is mitigated by devising local corrections to the quadrature scheme in the form of Cartesian Taylor expansions.This approach is suitably general,requiring only small modifications for application to other kernels,and can easily be incorporated into a fast multipole accelerated framework.The refined algorithm is evaluated with respect to both accuracy and efficiency using several analytic structures and the performance capacity is highlighted by the capability of accurately determining the field enhancement factor for a single nanotip electron cathode.
