Solid Mesh

In meshing a part or an assembly with solid elements, the software generates one of the following types of elements based on the active mesh options for the study:

• Draft quality mesh. The automatic mesher generates linear tetrahedral solid elements.

• High quality mesh. The automatic mesher generates parabolic tetrahedral solid elements.

Linear elements are also called first-order, or lower-order elements. Parabolic elements are also called second-order, or higher-order elements.

A linear tetrahedral element is defined by four corner nodes connected by six straight edges. A parabolic tetrahedral element is defined by four corner nodes, six mid-side nodes, and six edges. The following figures show schematic drawings of linear and parabolic tetrahedral solid elements.

In general, for the same mesh density (number of elements), parabolic elements yield better results than linear elements because: 1) they represent curved boundaries more accurately, and 2) they produce better mathematical approximations. However, parabolic elements require greater computational resources than linear elements.

For structural problems, each node in a solid element has three degrees of freedom that represent the translations in three orthogonal directions. The software uses the X, Y, and Z directions of the global Cartesian coordinate system in formulating the problem.

For thermal problems, each node has one degree of freedom which is the temperature.

High quality mesh is recommended for final analysis.