Automatic Finite Element Mesh Research Articles

Automatic Finite Element Mesh Generation on 3D Surfaces Based on STEP

Computer Aided Engineering (CAE) have a vital value in die and mould manufacturing. For the purpose of enhancing the modelling ability of the existing CAE analysis system and improving the mesh generation quality and working efficiency, a system for automatic finite element mesh generation on 3D surfaces is designed and implemented. Applying the neutral mechanism for product information sharing provided by STEP, product model import and reconstruction process is first implemented. And then product model information extraction module is developed aims at preparing geometrical and topological information for finite element mesh generation. An improved strategy for automatic triangular mesh generation over 3D surface is adopted to realize the mesh generation of the system. Implemented results indicate that the presented system helps to improve the mesh quality and at the same time increase the process efficiency and reduce the time cost.

Finite Element Modeling of Asphalt Mixture Based on Image Recognition

This study describes a method for establishing a mechanical model of heterogeneous finite element method. With the combination of digital image recognition technology and the theory of automatic mesh generation, it is possible to establish an inhomogeneous finite element model for mechanical calculation. Firstly, the micro-structure of the two-dimensional mixture is identified. Then all the boundary points are imported into ANSYS. Finally, the finite element mesh model of the micro-structure of the asphalt mixture is obtained by using the automatic finite element mesh generation technology. Taking Marshall specimen as an example, meshing the model proves that the method is feasible.

Safety Assessment of Damaged Multi-planar Square Hollow Section Welded Joints Using the New BS 910:2013+A1:2015

The safety assessment procedure in the new BS 7910:2013+A1:2015 guide is based on the failure assessment diagram (FAD) method. This paper aims to validate the above procedure for complex geometries such as damaged multi-planar square hollow section (SHS) welded joints and to recommend optimal solutions if necessary. FAD curves are constructed for cracked multi-planar SHS TT-, YT- and KT-joints for the first time and are compared with the Option 1 curve of the BS guide. A robust novel automatic finite element (FE) mesh generator, which is validated using the full-scale experimental test results, is used in this study. The new FE mesh generator addresses the issue of non-convergence by using a key-hole for the modelling the crack tip in elastic-plastic analyses. The new FE mesh generator is capable to model cracks and geometries of arbitrary dimensions and is able to achieve convergence of solutions even at a high plastic deformation. It is shown to be aiding in speedy generation of cracked FE mesh models which is otherwise time consuming to generate using commercial software packages. The results show that the Option 1 curve does not always guarantee safe solutions for multi-planar SHS welded joints. Hence, a penalty factor of 1.1 is recommended to be used to calculate the plastic collapse load. The use of proposed penalty factor gives optimal solutions for cracked multi-planar SHS TT-, YT- and KT-joints.

Automated Finite Element Analysis for Molding Behavior of PET Bottle

This paper describes an automated analysis methodology of 3D structures using optimal design system. An automatic finite element mesh generation technique, which is based on fuzzy knowledge processing and computational geometry techniques, is incorporated into the system, together with a commercial FE analysis code, and a commercial solid modeler. Also, with the aid of multilayer neural networks, the present system allows us to obtain automatically a design window in which a number of satisfactory design solutions exist in a multi-dimensional design parameter space. The developed automated FE analysis system is successfully applied to evaluate the molding behavior of PET bottles.

A New Approach to Automatic Generation of An All Pentagonal Finite Element Mesh For Numerical Computations Over Convex Polygonal Domains

A new method is presented for subdividing a large class of solid objects into topologically simple subregionssuitablefor automatic finite element meshing withpentagonalelements. It is known that one can improve the accuracy of the finite element solutionby uniformly refining a triangulation or uniformly refining a quadrangulation.Recently a refinement scheme of pentagonal partition was introduced in [31,32,33]. It is demonstrated that the numerical solutionbased on the pentagonal refinement scheme outperforms the solutions based on the traditional triangulation refinement scheme as well as quadrangulation refinement scheme. It is natural to ask if one can create a hexagonal refinement or general polygonal refinement schemes with a hope to offer even further improvement. It is shown in literature that one cannot refine a hexagon using hexagons of smaller size. In general, one can only refine an n-gon by n-gons of smaller size if n = 5. Furthermore, we introduce a refinement scheme of a generalpolygon based on the pentagon scheme. This paper first presents a pentagonalization (or pentagonal conversion) scheme that can create a pentagonal mesh from any arbitrary mesh structure. We also introduce a pentagonal preservation scheme that can create a pentagonal mesh from any pentagonal mesh.

An Automatic Method for Complete Triangular Mesh Conversion into Quadrilateral Mesh for Multiple Domain Geometry

This research developed an automatic two-dimensional finite element meshing system to resolve practical engineering problems in the fields of geology, hydrology, and water resources. This system first used the Delaunay triangulation method to create reasonable-density triangular mesh and then converted it into quadrilateral mesh by combining proper pairs of adjacent triangles. A series of combination patterns aiming at three cases were established. The effect of the number of boundary edges on the subsequent meshing procedures were studied and summarized. For the geometry with multiple domains an adjustment method is proposed to completely eliminate the residual triangles during quadrilateral meshing through adjusting the number of boundary edges in each loop to be even. A special boundary loop identification method is proposed for priority treatment. Corresponding treatment methods aimed at three different situations are established for common boundary loops. For a certain boundary loop with an odd number of boundary edges, the appropriate edge for new point insertion is determined by the position properties and relative density errors. Practical applications confirm that the method proposed in this paper could successfully implement the full conversion from the triangular mesh to the quadrilateral mesh.

Automated FE Analysis for Heat Sink of LED Modules

This paper describes an automatic finite element (FE) mesh generation for FE analysis of LED modules. It is consisting of element generation, bubble packing and solid geometry modeler. This automated FE analysis system including bubble packing method consists of three sub-processes: (a) definition of geometric model, i.e. analysis model, (b) generation of bubbles, and (c) generation of elements. One of commercial solid modelers is employed for three-dimensional solid structures. Bubble is generated if its distance from existing bubble points is similar to the bubble spacing function at the point. The Delaunay method is introduced as a basic tool for element generation. The developed system allows designers to evaluate detailed physical behaviors of structures through some simple interactive operations to their geometry models. To demonstrate practical performances of the present system, the system was used to an analysis of heat sink. Practical performances of the present system are demonstrated through several examples for heat sink of LED modules.

An algorithm for automatic 2D finite element mesh generation with line constraints

In this study, an algorithm is designed specifically for automatic finite element (FE) mesh generation on the transverse structure of hulls reinforced by stiffeners. Stiffeners attached to the transverse structure are considered as line constraints in the geometry boundary. For the FE mesh generation used in this study, the line constraints are treated as boundaries and by that means the geometry domain attached to the line constraints is decomposed into sub-domains, constrained only by the closed boundaries. Then, the mesh can be generated directly on those sub-domains by the traditional approach. The performance of the proposed algorithm is evaluated and the quality of the generated mesh meets expectations.

An automated CAE system for multidisciplinary structural design: its application to micro accelerometer

This paper describes a new computer-aided engineering system for multidisciplinary structural design. An automatic finite element mesh generation technique, based on fuzzy knowledge processing and computational geometry, is incorporated into the system, together with one of the commercial finite element analysis codes. A bubble is generated if its distance from existing bubble points is similar to the bubble-spacing function at the point. The bubble-spacing function is well controlled by fuzzy knowledge processing. The Delaunay method is employed as a basic tool for element generation. Automatic finite element generation for three-dimensional MEMS holds great benefits for analyses. An optimum design solution or satisfactory solutions will be automatically searched using the genetic algorithms modified for real search space, together with the automated finite element analysis system. A novel CAE system was developed, and successfully applied to the shape design of a micro accelerometer based on a tunneling current concept.

Fatigue study of partially overlapped circular hollow section K-joints. Part 1: Geometrical models and mesh generation

In this study, a set of consistent geometrical models is developed for fatigue assessment of partially overlapped circular hollow section K-joint. To accomplish the fatigue assessment, an accompanying set of automatic finite element mesh generation procedures is developed. These mesh generation procedures are able to discretize the geometrical models into different types of meshes for fatigue assessments of uncracked and cracked joints. The presentation of the work is divided into two parts. In Part 1, descriptions of the geometrical models and the mesh generation procedures are given. In Part 2, attention is focused on the validation of the numerical results.

피지이론과 버블기법을 이용한 3차원 구조물의 유한요소해석을 위한 요소생성기법

본 논문은 3차원구조물의 유한요소해석을 위한 자동 유한요소 생성에 관한 것으로 퍼지이론과 버블요소 생성기법, 상용 솔리드모델러로 구성되어진다. 새로운 요소생성과정은 (a) 해석모델인 형상모델링 정의, (b) 버블생성, 그리고 (c) 요소생성으로 이루어진다. 형상모델링에는 상용 솔리드모델러를 이용하였으며 버블은 각 지점에서의 버블간격함수에 의해 생성되어진다. 버블간격 함수는 지식처리수법에 의해 조절되어 진다. 요소생성을 위해서는 기본적으로 데로우니방법을 도입하였다. 이러한 3차원 구조물에 대한 유한요소의 자동생성은 해석을 위해 큰 잇점이 있다. 실제적인 현 시스템의 효용성을 검증하기위해 3차원 형상에 대한 예를 제시하였다. This paper describes an automatic finite element mesh generation for finite element analysis of three-dimensional structures. It is consisting of fuzzy knowledge processing, bubble meshing and solid geometry modeler. This novel mesh generation process consists of three subprocesses: (a) definition of geometric model, i.e. analysis model, (b) generation of bubbles, and (c) generation of elements. One of commercial solid modelers is employed for three-dimensional solid structures. Bubble is generated if its distance from existing bubble points is similar to the bubble spacing function at the point. The bubble spacing function is well controlled by the fuzzy knowledge processing. The Delaunay method is introduced as a basic tool for element generation. Automatic generation of finite element for three-dimensional solid structures holds great benefits for analyses. Practical performances of the present system are demonstrated through several mesh generations for 3D geometry.

Parametric Design on Bellows of Piping System Using Fuzzy Knowledge Processing

This paper describes a novel automated analysis system for bellows of piping system. An automatic finite element (FE) mesh generation technique, which is based on the fuzzy theory and computational geometry technique, is incorporated into the system, together with one of commercial FE analysis codes and one of commercial solid modelers. In this system, a geometric model, i.e. an analysis model, is first defined using a commercial solid modelers for 3-D shell structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay triangulation technique is introduced as a basic tool for element generation. The triangular elements are converted to quadrilateral elements. Practical performances of the present system are demonstrated through several analysis for bellows of piping system.

Parametric Study on Bellows of Piping System Using Fuzzy Theory

This paper describes a novel automated analysis system for bellows of piping system. An automatic finite element (FE) mesh generation technique, which is based on the fuzzy theory and computational geometry technique, is incorporated into the system, together with one of commercial FE analysis codes and one of commercial solid modelers. In this system, a geometric model, i.e. an analysis model, is first defined using a commercial solid modelers for 3-D shell structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay triangulation technique is introduced as a basic tool for element generation. The triangular elements are converted to quadrilateral elements. Practical performances of the present system are demonstrated through several analysis for bellows of piping system.

퍼지이론을 이용한 FEM 모델링을 위한 자동 요소분할 시스템

This paper describes an automatic finite element (FE) mesh generation for three-dimensional structures consisting of free-form surfaces. This mesh generation process consists of three subprocesses: (a) definition of geometric model, i.e. analysis model, (b) generation of nodes, and (c) generation of elements. One of commercial solid modelers is employed for three-dimensional solid structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay method is introduced as a basic tool for element generation. Automatic generation of FE meshes for three-dimensional solid structures holds great benefits for analyses. Practical performances of the present system are demonstrated through several mesh generations for three-dimensional complex geometry.

An ANN-based element extraction method for automatic mesh generation

This paper proposes an artificial neural network based element extraction method for automatic finite element mesh generation. A finite element mesh is a discretized representation of a geometric domain. A domain is discretized into elements, which may be triangles, quadrilaterals, tetrahedron, or hexahedron. The element extraction method repeatedly generates element (s) within the domain using some predefined ‘if-then’ rules until the whole domain is filled with required elements. This method has an advantage of creating meshes for domains with complex boundaries. However, the ‘if-then’ rules for element extraction are usually difficult to acquire, because these rules not only generate elements but also change the problem they are designed to solve. In this paper, a Back-Propagation (BP) neural network is used to represent the ‘if-then’ element extraction rules and to train the relationship behind these rules. The input for this network includes the coordinates of some boundary points while the output defines the parameters for extracting an element. In order to generate good quality element while keeping the updated problem still solvable, the design and definition of the neural network is more complex than those in the traditional classification problems. This paper discusses issues related to the design of the neural network for element extraction. Numerical experiments on quadrilateral mesh generation have shown that this method is effective.

Optimisation algorithm for the design of bushing for indoor SF6 switchgear applications

An algorithm is presented for the development and optimisation of medium-voltage bushing built-in SF6 switchgear using numerical calculations on the basis of the finite-element method. The algorithm also enables a universal approach to the design of other medium-voltage switchgear elements. It includes the use of numerical analysis with a newly developed automatic finite-element mesh generator, parametrisation of the input data algorithm, and the use of an automated optimisation algorithm. The main emphasis is on an approach to modelling on the basis of evolution strategy optimisation.

Development of High-Performance FEM Modeling System Based on Fuzzy Knowledge Processing

This paper describes an automatic finite element (FE) mesh generation for three-dimensional structures consisting of tree-form surfaces. This mesh generation process consists of three subprocesses: (a) definition of geometric model, (b) generation of nodes, and (c) generation of elements. One of commercial solid modelers is employed for three-dimensional solid structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Voronoi diagram method is introduced as a basic tool for element generation. Automatic generation of FE meshes for three-dimensional solid structures holds great benefits for analyses. Practical performances of the present system are demonstrated through several mesh generations for three-dimensional complex geometry.

인공지능을 이용한 3차원 구조물의 최적화 설계 : 마이크로 가속도계에 적용

본 논문은 실질적인 최적화 구조물의 설계를 위한 시스템에 대한 것으로 퍼지이론에 바탕을 둔 자동 유한요소 생성 망 기술과 계산 기하학적 기술, 해석코드 및 솔리드모델러를 시스템에 통합시켰다. 최적해 또는 만족해는 자동해석 시스템과 함께 탐색공간을 위한 유전자 알고리즘을 이용하여 자동적으로 탐색되어 진다. 또한, 유전자 알고리즘을 이용함으로써 본 설계 시스템은 다차원 해를 얻을 수 있다. 개발된 시스템은 터널전류에 바탕을 둔 마이크로 가속도계의 형상설계에 적용하였다. This paper describes an optimal design system for multi-disciplinary structural design. An automatic finite element (FE) mesh generation technique, which is based on the fuzzy knowledge processing and computational geometry technique, is incorporated into the system, together with a commercial FE analysis code and a commercial solid modelers. An optimum design solution or satisfactory solutions are then automatically searched using the genetic algorithms modified for real search space, together with the automated FE analysis system. With an aid of genetic algorithms, the present design system allows us to effectively obtain a multi-dimensional solutions. The developed system is successfully applied to the shape design of a micro accelerometer based on a tunnel current concept.

Finite element modeling of geomaterials using digital image processing

This paper presents a digital image processing based finite element method for the two-dimensional mechanical analysis of geomaterials by actually taking into account their material inhomogeneities and microstructures. The proposed method incorporates the theories and techniques of digital image processing, the principles of geometry vectorization and the techniques of automatic finite element mesh generation into the conventional finite element methods. Digital image techniques are used to acquire the inhomogeneous distributions of geo-materials including soils, rocks, asphalt concrete and cement concrete in digital format. Digital image processing algorithms are developed to identify and classify the main homogeneous material types and their distribution structures that form the inhomogeneity of a geomaterial in the image. The interfaces of the main homogeneous material types are vectorized to form the internal material geometric structure and sub-regions. The vectorized digital images are used as inputs for finite element mesh generations using automatic mesh generation techniques. Lastly, the conventional finite element methods are employed to carry out the computation and analysis of geomechanical problems by taking into account the actual internal inhomogeneity of the geomaterial. Using asphalt concrete as an example, the paper gives a detailed explanation of the proposed digital image processing based finite element method. The paper further applies the new method to the mechanical analysis of the so-called Brazilian indirect tensile test in rock mechanics and pavement engineering. The numerical results show that this new digital image process based finite element method can take into account the material inhomogeneities in the geomechanical analysis which can have significant effects on the tensile stress distribution along the loading axis of the Brazilian indirect tensile tests.

A modeling methodology for finite element mesh generation of multi-region models with parametric surfaces

This paper presents a description of the reorganization of a geometric modeler, MG, designed to support new capabilities of a topological module (CGC) that allows the detection of closed-off solid regions described by surface patches in non-manifold geometric models defined by NURBS. These patches are interactively created by the user by means of the modeler's graphics interface, and may result from parametric–surface intersection in which existing surface meshes are used as a support for a discrete definition of intersection curves. The geometry of realistic engineering objects is intrinsically complex, usually composed by several materials and regions. Therefore, automatic and adaptive meshing algorithms have become quite useful to increase the reliability of the procedures of a FEM numerical analysis. The present approach is concerned with two aspects of 3D FEM simulation: geometric modeling, with automatic multi-region detection, and support to automatic finite-element mesh generation.