为了对不均匀介质中物理场进行更有效的多尺度模拟,提出一种称为有限点集-网格元法的数值方法(finite point-grid element method,FPGEM).FPGEM是对传统有限元方法的改造,它把网格与节点分离成独立的两套覆盖,采用离散的有限点集对物理...为了对不均匀介质中物理场进行更有效的多尺度模拟,提出一种称为有限点集-网格元法的数值方法(finite point-grid element method,FPGEM).FPGEM是对传统有限元方法的改造,它把网格与节点分离成独立的两套覆盖,采用离散的有限点集对物理场进行多尺度逼近,同时采用网格剖分作为介质分布的几何载体;点集和网格各自扮演不同的角色,发挥不同的功能.FPGEM主要的优点是:由于其节点和网格分离,对场的非均匀性及介质非均匀分布具有双重的多尺度模拟的优势,为一些地球物理问题中的多尺度模拟提供了一种更加灵活、自然的计算框架.展开更多
A computational framework for parachute inflation is developed based on the immersed boundary/finite element approach within the open-source IBAMR library.The fluid motion is solved by Peskin's diffuse-interface i...A computational framework for parachute inflation is developed based on the immersed boundary/finite element approach within the open-source IBAMR library.The fluid motion is solved by Peskin's diffuse-interface immersed boundary(IB)method,which is attractive for simulating moving-boundary flows with large deformations.The adaptive mesh refinement technique is employed to reduce the computational cost while retain the desired resolution.The dynamic response of the parachute is solved with the finite element approach.The canopy and cables of the parachute system are modeled with the hyperelastic material.A tether force is introduced to impose rigidity constraints for the parachute system.The accuracy and reliability of the present framework is validated by simulating inflation of a constrained square plate.Application of the present framework on several canonical cases further demonstrates its versatility for simulation of parachute inflation.展开更多
A numerical method for coupled deformation between sheet metal and flexible-die was proposed. Based on the updated Lagrangian （UL） formulation, the elastoplastic deformation of sheet metal was analyzed with finite e...A numerical method for coupled deformation between sheet metal and flexible-die was proposed. Based on the updated Lagrangian （UL） formulation, the elastoplastic deformation of sheet metal was analyzed with finite element method （FEM） and the bulk deformation of flexible-die was analyzed with element-free Galerkin method （EFGM）. The frictional contact between sheet metal and flexible-die was treated by the penalty function method. The sheet elastic flexible-die bulging process was analyzed with the FEM-EFGM program for coupled deformation between sheet metal and bulk flexible-die, called CDSB-FEM-EFGM for short. Compared with finite element code DEFORM-2D and experiment results, the CDSB-FEM-EFGM program is feasible. This method provides a suitable numerical method to analyze sheet flexible-die forming.展开更多
This paper describes two modified methods for triangular and quadrilateral meshing for finite element analysis of 2D electric machines. One is coupling the classic Delaunay method and advancing front method to generat...This paper describes two modified methods for triangular and quadrilateral meshing for finite element analysis of 2D electric machines. One is coupling the classic Delaunay method and advancing front method to generate optimal triangulation; the other is coupling the classic paving and Delaunay triangulation for optimal quadrilateral meshing. Various electric machine models are meshed successfully to demonstrate the robustness and effectiveness of the methods.展开更多
A method for encoding and compressing finite element models is proposed. Themodel may be various non-simple topological structures and contain any combinations of beams,triangular elements and quadrilateral elements. ...A method for encoding and compressing finite element models is proposed. Themodel may be various non-simple topological structures and contain any combinations of beams,triangular elements and quadrilateral elements. First the model is subdivided into simple meshesthat are orientable and manifold. Based on the Edgebreaker algorithm, 13 labelled pairs areintroduced for quadrilateral meshes and five other labelled pairs are introduced for triangles. Thenthe connectivity information of mixed triangle/quadrilateral meshes is coded in a direct manner.Two other bits are used to record the wireframe information. For the pure wireframe model, Taubin'smethod is extended to compress it. The compression algorithm is implemented and evaluated.Experiments with several models show that the method achieves excellent compression ratios.展开更多
The conventional finite-element（FE） method often uses a structured mesh, which is designed according to the user’s experience, and it is not sufficiently accurate and flexible to accommodate complex structures such...The conventional finite-element（FE） method often uses a structured mesh, which is designed according to the user’s experience, and it is not sufficiently accurate and flexible to accommodate complex structures such as dipping interfaces and rough topography. We present an adaptive FE method for 2.5D forward modeling of induced polarization（IP）. In the presented method, an unstructured triangulation mesh that allows for local mesh refinement and flexible description of arbitrary model geometries is used. Furthermore, the mesh refinement process is guided by dual error estimate weighting to bias the refinement towards elements that affect the solution at the receiver locations. After the final mesh is generated, the Jacobian matrix is used to obtain the IP response on 2D structure models. We validate the adaptive FE algorithm using a vertical contact model. The validation shows that the elements near the receivers are highly refined and the average relative error of the potentials converges to 0.4 % and 1.2 % for the IP response. This suggests that the numerical solution of the adaptive FE algorithm converges to an accurate solution with the refined mesh. Finally, the accuracy and flexibility of the adaptive FE procedure are also validated using more complex models.展开更多
文摘为了对不均匀介质中物理场进行更有效的多尺度模拟,提出一种称为有限点集-网格元法的数值方法(finite point-grid element method,FPGEM).FPGEM是对传统有限元方法的改造,它把网格与节点分离成独立的两套覆盖,采用离散的有限点集对物理场进行多尺度逼近,同时采用网格剖分作为介质分布的几何载体;点集和网格各自扮演不同的角色,发挥不同的功能.FPGEM主要的优点是:由于其节点和网格分离,对场的非均匀性及介质非均匀分布具有双重的多尺度模拟的优势,为一些地球物理问题中的多尺度模拟提供了一种更加灵活、自然的计算框架.
基金supported by the Open Project of Key Laboratory of Aerospace EDLA,CASC(No.EDL19092208)。
文摘A computational framework for parachute inflation is developed based on the immersed boundary/finite element approach within the open-source IBAMR library.The fluid motion is solved by Peskin's diffuse-interface immersed boundary(IB)method,which is attractive for simulating moving-boundary flows with large deformations.The adaptive mesh refinement technique is employed to reduce the computational cost while retain the desired resolution.The dynamic response of the parachute is solved with the finite element approach.The canopy and cables of the parachute system are modeled with the hyperelastic material.A tether force is introduced to impose rigidity constraints for the parachute system.The accuracy and reliability of the present framework is validated by simulating inflation of a constrained square plate.Application of the present framework on several canonical cases further demonstrates its versatility for simulation of parachute inflation.
基金Project(51275130)supported by the National Natural Science Foundation of China
文摘A numerical method for coupled deformation between sheet metal and flexible-die was proposed. Based on the updated Lagrangian （UL） formulation, the elastoplastic deformation of sheet metal was analyzed with finite element method （FEM） and the bulk deformation of flexible-die was analyzed with element-free Galerkin method （EFGM）. The frictional contact between sheet metal and flexible-die was treated by the penalty function method. The sheet elastic flexible-die bulging process was analyzed with the FEM-EFGM program for coupled deformation between sheet metal and bulk flexible-die, called CDSB-FEM-EFGM for short. Compared with finite element code DEFORM-2D and experiment results, the CDSB-FEM-EFGM program is feasible. This method provides a suitable numerical method to analyze sheet flexible-die forming.
文摘This paper describes two modified methods for triangular and quadrilateral meshing for finite element analysis of 2D electric machines. One is coupling the classic Delaunay method and advancing front method to generate optimal triangulation; the other is coupling the classic paving and Delaunay triangulation for optimal quadrilateral meshing. Various electric machine models are meshed successfully to demonstrate the robustness and effectiveness of the methods.
文摘A method for encoding and compressing finite element models is proposed. Themodel may be various non-simple topological structures and contain any combinations of beams,triangular elements and quadrilateral elements. First the model is subdivided into simple meshesthat are orientable and manifold. Based on the Edgebreaker algorithm, 13 labelled pairs areintroduced for quadrilateral meshes and five other labelled pairs are introduced for triangles. Thenthe connectivity information of mixed triangle/quadrilateral meshes is coded in a direct manner.Two other bits are used to record the wireframe information. For the pure wireframe model, Taubin'smethod is extended to compress it. The compression algorithm is implemented and evaluated.Experiments with several models show that the method achieves excellent compression ratios.
基金financially supported by the National Natural Science Foundation of China(No.41204055,41164003,and 41104074)Opening Project(No.SMIL-2014-06) of Hubei Subsurface Multi-scale Imaging Lab(SMIL),China University of Geosciences(Wuhan)
文摘The conventional finite-element（FE） method often uses a structured mesh, which is designed according to the user’s experience, and it is not sufficiently accurate and flexible to accommodate complex structures such as dipping interfaces and rough topography. We present an adaptive FE method for 2.5D forward modeling of induced polarization（IP）. In the presented method, an unstructured triangulation mesh that allows for local mesh refinement and flexible description of arbitrary model geometries is used. Furthermore, the mesh refinement process is guided by dual error estimate weighting to bias the refinement towards elements that affect the solution at the receiver locations. After the final mesh is generated, the Jacobian matrix is used to obtain the IP response on 2D structure models. We validate the adaptive FE algorithm using a vertical contact model. The validation shows that the elements near the receivers are highly refined and the average relative error of the potentials converges to 0.4 % and 1.2 % for the IP response. This suggests that the numerical solution of the adaptive FE algorithm converges to an accurate solution with the refined mesh. Finally, the accuracy and flexibility of the adaptive FE procedure are also validated using more complex models.
