Quadrilateral only meshing

You can set the Attempt Quad Only option in the 2D Mesh dialog box to On - Zero Triangles to create a mesh of only quadrilateral elements. For the software to generate an all quadrilateral mesh on a face, the number of elements on all edges of that face must add up to an even number. This requirement is known as mesh parity.

Note:

The On - Zero Triangles is available only when both the Attempt Multi-Block Decomposition and Attempt Free Mapped Meshing check boxes are cleared.

The software cannot generate a quadrilateral only mesh if:

• The number of elements on all edges of that face adds up to an odd number.

• The number of elements on all the edges of a face cannot be modified because, for example, of existing Mesh Controls or Mesh Mating Conditions.

Example: Quadrilateral only mapped mesh on a three-sided face

Consider the example of a mesh on a three-sided face in which the number of elements on each edge (M, N, and O) is different.

For the software to generate a quadrilateral only mapped mesh on this face, the sum of the number of elements on edges M, N, and O must be an even number.

Internally, the software divides the face into three sub-areas, as shown in the following graphic, using the approximate center of gravity (CG) of the face. The edges are divided as follows:

• M splits into m1 and m2

• N splits into n1 and n2

• O splits into o1 and o2

For the software to generate the quadrilateral-only mapped mesh, the number of elements on each edge must meet the following conditions:

• m1+ m2 = M, n1+ n2 = N, o1+ o2 = O

• m1 = n2, n2 = o2, o1 = m2

The software then creates the mapped mesh on each sub-area and smooths those individual meshes out as one mesh on the entire face, as shown in the following graphic.

Mesh points on the interior of a face

A mesh in a structural analyses needs to honor the location of mesh points. A mesh point can represent, for example, the location of a load application point or the location of a seam or spot weld. However, the presence of mesh points on the interior of a face can make the generation of a high quality, quadrilateral-only mapped mesh challenging.

If the face on which you want to create a quadrilateral only mapped mesh contains mesh points, the software uses a technique that tries to honor the locations of those points without sacrificing the overall quality of the mesh. In these cases, the software tries to reflect every mesh point on the interior of a face onto the boundaries (sides) of a four-sided face.

Initially, the reflection of the interior points onto the boundary causes the boundary discretization to become non-uniform. When this occurs, the software uses a boundary blended, bi-linear transfinite interpolation technique to ensure that the mesh line flow is smooth and the overall mesh has good quality.

Note that:

• The software is not able to use this technique to reflect interior mesh points onto the boundary of three-sided faces.

• If a face is curved, the software may be unable to reflect the mesh points onto the boundary. To avoid this limitation, you can try to reduce the curvature of the face by splitting the face into smaller, regions with less curvature.

• If a face contains mesh points on its boundary as well as on its interior, the software may be unable to reflect the interior mesh points onto the boundary.

How do I

Create a 2D free mesh

Learn more

2D free meshing

Using pre-defined favorite settings to create 2D meshes

Understanding the 2D meshing methods

Understanding free mapped meshes

Understanding free mesh generation

Fixing triangular element interior angle quality issues

About CAD curvature abstraction

Midnode placement for parabolic elements

Creating a separate mesh for each face or polygon body

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

Browse Simcenter 3D help by product area

Quadrilateral only meshing, Simcenter 3D 2021.1 Series

© 2020 Siemens

window.mainLanguage="en_US"

window.delivId=""

window.projectId=""

MathJax.Hub.Config({ TeX: { extensions: ["autoload-all.js"] }, tex2jax: { displayMath: [ ] }, "SVG": { scale: 125 } });