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Meshing Quality

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Mesh Quality Control

 

Online Repairing, Fixing and Meshing Service for CAD and CAE Models

 

Correction of data, whether geometrical or triangulated.

Cleaner for mesh correction.

Remeshing and Mesh Boolean Operations.

Surface meshing from both analytical CAD and discrete CAD (tessellation).

Triangular mesh generation.

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The shape of elements in FE Analysis must be distorted from their ideal shapes when meshing the irregular or complex geometric shapes. Every element is designed to work properly within a certain range of shape distortion. Exactly how much distortion and what type of distortion is allowed before an element degenerates depends on factors such as element type, numerical procedures used in the element design, etc.

The major types of degeneration are Aspect Ratio, Skewness and Warping Angle.

Application of a definite quality control consists of usage of the corresponding algorithm, which calculates a value of a definite geometric characteristic (Area, Length of edges, etc.) for all meshing elements, composing your mesh. Then all meshing elements are colored according the calculated values. The reference between the coloring of the meshing elements and these calculated values is shown with the help of a scalar bar, which is displayed near the presentation of your mesh.

There are three types of quality controls corresponding to face entity type .

 

Note : The quality criteria are applied only on the first visible model in the explorer.

To apply the quality control criterion to your mesh:

1.       Import your mesh into the viewer.

2.       Activate and in the toolbar.

3.       Choose Quality Controls > Quality Criteria in the upper left navigation menu.

Your mesh will be displayed in the viewer with its elements colored according to the applied mesh quality control criterion:

 

Aspect Ratio

 

 

The  aspect ratio  quality criterion for mesh elements reveals the degree of conformity of a mesh element to the regular element of its type (with all edges having the same length).

The ratio between largest and smallest characteristic dimension of an element is known as the Aspect Ratio.

Large aspect ratios increase the inaccuracy of the finite element representation and have a detrimental effect on convergence of Finite Element Solutions.

An aspect ratio of 1 is ideal but cannot always be maintained. In general, the aspect ratios are maintained from 1 to 5 at critical areas in a domain where derivatives of field variable are significant.

Along with solution accuracy the poor element shapes will often cause convergence problems in nonlinear analysis.

 

Warping

 

 

-           Ideally all the nodes of quadrilateral element should lie on the same plane, except at curvatures and complicated geometry profiles where this is not possible. "Measure of out of planeness of a Quadrilateral is Warping Factor or Warping Angle".

-           Warping calculation for triangular elements is not applicable, since three points define a plane, this check only applies to quads.

Warping Angle:

-           It is defined as angle between normal of two(triangular) planes formed by splitting the quad element along diagonals. Maximum Angle out of the two possibilities is reported as "Warp Angle".

-           In the case of solid elements, an element's face deviates from being planar. The quad is divided into two triangles along its diagonal, and the angle between the triangles normal is measured.

-           Ideal Value = 0 deg. (Acceptable < 5 deg. to 10 deg.)

 

Skewness

 

 

Skewness is the Angular Measure of Element Quality with respect to the Angles of Ideal Element Types. It is one of the Primary Qualities Measures of FE Mesh. Skewness determines how close to ideal (i.e., equilateral) a face or cell is. There are two different methods for calculating Skewness for 2D elements.

Calculation of Skewness for Triangular/Quadrilateral Elements (Normalized angle deviation).

In the normalized angle deviation method, skewness is defined (in general) as "maximum of ratio of Angular deviation from Ideal Element.

 

Supported Formats

Upload Formats Extensions

CAD: iges, igs, step, stp.

Design: stl, obj.

CAE: nas (Nastran BULK), pc (PamCrash), inp (Abaqus), mesh (MeshGems)

ZIP files for mesh, stl or obj (multi-files)

ZIP files for Nastran, PamCrash or Abaqus (include files)

Download Formats Extensions

Design extensions: stl, obj

CAE: nas (Nastran BULK), pc (PamCrash), inp (Abaqus), mesh (MeshGems)