scholarly journals Creating the finite element mesh of non-periodic masonry from the measurement of its geometrical characteristics: a novel automated procedure

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 23
Author(s):  
Simone Tiberti ◽  
Gabriele Milani
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Finite Element Mesh ◽  
Element Mesh ◽  
Plane Failure ◽  
Geometrical Characteristics ◽  
Image File ◽  
Historical Masonry ◽  
The Creation ◽  
Periodic Arrangement

This paper presents an automated procedure that enables the creation of a finite element mesh directly from the image file representing the rasterized sketch of a generic masonry element. This procedure goes under the name “pixel strategy” if a 2D finite element mesh is needed, where the elements are planar and rectangular; conversely, its extension in the 3D case is named “voxel strategy”, and there the resulting finite elements are solid bricks. The finite element meshes so obtained are then used for extracting homogenized in-plane failure surfaces for historical masonry cells, which display a non-periodic arrangement of units. These surfaces are consistent with the expected results, and their shapes suggest that the behavior of such type of masonry may range between orthotropic (if bed mortar joints are clearly noticeable) and quasi-isotropic (if some units spread over two or more masonry layers).

scholarly journals Development of a refinement algorithm for tetrahedral finite elements

2020 ◽  
Vol 36 ◽  
Author(s):  
A. Hermosillo-Arteaga ◽  
M. Romo-Organista ◽  
R. Magaña del Toro ◽  
J. Carrera-Bolaños
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Finite Element Mesh ◽  
Time Dependent ◽  
Triangular Element ◽  
Soil Consolidation ◽  
Element Mesh ◽  
Engineering Problems ◽  
Close Form ◽  
Refinement Algorithm

Many of the engineering problems are analyzed using numerical methods such as the finite element (FEM) whose results provide a basis to make basic decisions regarding the design of many important works. It is commonly accepted that FEM computations are reliable; however, the results may be affected by the configuration of the finite element mesh to simulate the medium to be analyzed, this is particularly true when the internal and external boundaries are time dependent, as is the case of soil consolidation. Accordingly, a thorough investigation was carried out with the main purpose of eliminating this shortcoming. The main steps to carried out the development of the innovative geometric procedure to automatically refine finite element tetrahedra-type (3D) are described. This geometric algorithm is based on the theory of fractals and is a generalization of the algorithm for triangular element finite element meshes (2D) [1,2]. This paper presents the fundaments of this new algorithm and shows its great approximation using 3D close form solutions, and its versatility to adapt the original Finite Element Mesh when the load boundary conditions are modified (Neumann conditions).

scholarly journals ASSESSMENT OF FEM CALCULATION RESULTS ACCURACY WITH THE USE OF SYMMETRY PLANES IN GEOTECHNICAL PROBLEMS

2020 ◽  
Vol 11 (2) ◽  
pp. 28-39
Author(s):  
R. V Melnikov ◽  
E. P Bragar
Keyword(s):  
Finite Element ◽  
Shallow Foundation ◽  
Finite Element Mesh ◽  
Scale Model ◽  
Deep Excavation ◽  
Element Mesh ◽  
Foundation Slab ◽  
Calculation Results ◽  
The Creation ◽  
Geotechnical Problems

To calculate different geotechnical objects (foundations of unique buildings, pile foundation grillages, slab foundations, embankments, etc.) we often need to simplify geometric model. Use of symmetry principles allows to simplify the model without reducing its detail. A relevant issue with the use of symmetry planes is the assessment of calculation results accuracy. The article considers the research of such an assessment for two traditional geotechnical problems: a shallow foundation slab and a shoring of deep excavation. Calculations have been performed with various options of symmetry planes usage: a full-scale model, using one symmetry plane, using two symmetry planes; differences in the ways of representing building structures: 2D and 3D continuum elements. Generating the finite element mesh, we took into account the fact, that the degree of mesh grinding significantly influence the accuracy of the calculation results. That’s why the finite element mesh was divided into two areas: the area of «interest» represented by small sized elements, and the «peripheral» area created by larger elements. We also considered the sequence of technological processes: the initial stage of the calculation is the creation of the initial stress state, the next stage is the creation of the structure (foundation slab, shoring of excavation), the final stage is the force application. The calculation results were evaluated according to the criteria related to the second group of limit states. The controlled parameters for the shallow foundation slab were: maximum and average settlement, relative difference of settlements; for the shoring of deep excavation - the maximum displacement of the enclosure structure. It was found out that to present the construction in the form of 2D-elements it is necessary to introduce additional boundary conditions. They prevent rotation in nodes located on the plane of symmetry. The authors make conclusions and recommendations for creating design models with the use of symmetry planes.

scholarly journals Influence of finite element mesh size on the carrying capacity analysis of single-row ball slewing bearing

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Peiyu He ◽  
Qinrong Qian ◽  
Yun Wang ◽  
Hong Liu ◽  
Erkuo Guo ◽  
...  
Keyword(s):  
Finite Element ◽  
Carrying Capacity ◽  
Mesh Size ◽  
Finite Element Mesh ◽  
Fe Model ◽  
Element Mesh ◽  
Heavy Load ◽  
Slewing Bearing ◽  
Maximum Contact ◽  
Slewing Bearings

Slewing bearings are widely used in industry to provide rotary support and carry heavy load. The load-carrying capacity is one of the most important features of a slewing bearing, and needs to be calculated cautiously. This paper investigates the effect of mesh size on the finite element (FE) analysis of the carrying capacity of slewing bearings. A local finite element contact model of the slewing bearing is firstly established, and verified using Hertz contact theory. The optimal mesh size of finite element model under specified loads is determined by analyzing the maximum contact stress and the contact area. The overall FE model of the slewing bearing is established and strain tests were performed to verify the FE results. The effect of mesh size on the carrying capacity of the slewing bearing is investigated by analyzing the maximum contact load, deformation, and load distribution. This study of finite element mesh size verification provides an important guidance for the accuracy and efficiency of carrying capacity of slewing bearings.

Optimization of a finite element mesh for plates subjected to in-plane patch loading

2019 ◽  
Vol 33 (3) ◽  
pp. 1185-1193 ◽  
Author(s):  
Ghania Ikhenazen ◽  
Messaoud Saidani ◽  
Madina Kilardj
Keyword(s):  
Finite Element ◽  
Finite Element Mesh ◽  
Element Mesh ◽  
Patch Loading

A hybrid method for terminating the finite-element mesh (electrostatic case)

1995 ◽  
Vol 8 (6) ◽  
pp. 282-287 ◽  
Author(s):  
Tanmoy Roy ◽  
Tapan K. Sarkar ◽  
Antonije R. Djordjevic ◽  
Magdalena Salazar-Palma
Keyword(s):  
Finite Element ◽  
Hybrid Method ◽  
Finite Element Mesh ◽  
Element Mesh

Finite Element Mesh Generator Applying Constraints’ Propagation and Isoparametric Mapping

1991 ◽  
Author(s):  
J. Rodriguez ◽  
M. Him
Keyword(s):  
Finite Element ◽  
Mesh Generation ◽  
Element Model ◽  
Finite Element Mesh ◽  
Fe Model ◽  
Element Analysis ◽  
Element Mesh ◽  
Mesh Generator ◽  
Generation Algorithm ◽  
Essential Input

Abstract This paper presents a finite element mesh generation algorithm (PREPAT) designed to automatically discretize two-dimensional domains. The mesh generation algorithm is a mapping scheme which creates a uniform isoparametric FE model based on a pre-partitioned domain of the component. The proposed algorithm provides a faster and more accurate tool in the pre-processing phase of a Finite Element Analysis (FEA). A primary goal of the developed mesh generator is to create a finite element model requiring only essential input from the analyst. As a result, the generator code utilizes only a sketch, based on geometric primitives, and information relating to loading/boundary conditions. These conditions represents the constraints that are propagated throughout the model and the available finite elements are uniformly mapped in the resulting sub-domains. Relative advantages and limitations of the mesh generator are discussed. Examples are presented to illustrate the accuracy, efficiency and applicability of PREPAT.

A Constrained Optimization Approach to Finite Element Mesh Smoothing

1991 ◽  
Author(s):  
V. N. Parthasarathy ◽  
Srinivas Kodiyalam
Keyword(s):  
Finite Element ◽  
Constrained Optimization ◽  
Finite Element Mesh ◽  
Optimization Approach ◽  
Element Mesh ◽  
Initial Mesh ◽  
Nodal Coordinates ◽  
Automatic Mesh ◽  
Mesh Generators

Abstract The quality of a finite element solution has been shown to be affected by the quality of the underlying mesh. A poor mesh may lead to unstable and lor inaccurate finite element approximations. Mesh quality is often characterized by the “smoothness” or “shape” of the elements (triangles in 2-D or tetrahedra in 3-D). Most automatic mesh generators produce an initial mesh where the aspect ratio of the elements are unacceptably high. In this paper, a new approach to produce acceptable quality meshes from an initial mesh is presented. Given an initial mesh (nodal coordinates and element connectivity), a “smooth” final mesh is obtained by solving a constrained optimization problem. The variables for the iterative optimization procedure are the nodal coordinates (excluding, the boundary nodes) of the finite element mesh, and appropriate bounds are imposed on these to prevent an unacceptable finite element mesh. Examples are given of the application of the above method for 2/3-D triangular meshes generated using a QUADTREE | OCTREE automatic mesh generators. Results indicate that the new method not only yields better quality elements when compared with the traditional Laplacian smoothing, but also guarantees a valid mesh unlike the Laplacian method.

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