The Tetra mesh method is a Delaunay tetra mesher with an advancing-front point insertion technique used for mesh refinement. The Patch Conforming Tetra mesh method provides:
Support for 3D inflation
Built-in pyramid layer for conformal quad-tet transition
Built-in growth and smoothness control. The mesher tries to create a smooth size variation based on the specified growth factor.
Removes features under a certain size (Mesh Defeaturing).
Remember the following information when using the Patch Conforming Tetra mesh method:
When Patch Conforming Tetra meshing (with Physics Preference of ) fails due to lack of available memory, an error message is issued. However, this error message does not identify insufficient memory as the cause because meshing stops before the memory limit is reached. You may not notice any unusual behavior.
Patch Conforming Method Details view has the following options:
Scope
Scoping Method: Allows you to scope geometry bodies or named selection. The default value is Geometry Selection.
Geometry Selection: Allow you to scope the geometry bodies. When you select Geometry Selection, the Geometry allows you to select the geometry from the Geometry window.
Named Selection: Allow you to scope bodies grouped under a named selection.
Definition
Suppressed: Allows you to suppress the selected control. The default value is No. When Suppressed is set to Yes, Active displays the status of the selected control. Active is read-only.
Method: Allows you to select method.
Algorithm: Allows you to select the algorithm. The available options are Patch Conforming and Patch Independent. The default value is Patch Conforming.
Element Order: Allows you to select the element order. The default value is Use Global Setting. For information about the Element Order option, refer Method Controls and Element Order Settings.
Advanced Improve Options
Aggressive Thin Face Collapse: Allow you to defeature the thin faces when the size of the thin faces is less than twice of the target Characteristics Length, when Aggressive Thin Face Collapse is set to Program Controlled. Aggressive Thin Face Collapse is available only when Physics Preference is set to Explicit. The default value is Program Controlled.
Automatic Node Movement: Allows you to move nodes to meet the target mesh quality criteria for a given Physics Preference. At the end of tetrahedral meshing, an optimization algorithm finds the elements exceeding the target quality and automatically move the nodes to improve the quality of the elements. When multiple quality targets exist, the node movement is performed sequentially on the different target criteria. For example, When Physics Preference is Explicit, performs Automatic Node Movement first for Element Quality, then Aspect Ratio (Explicit) and finally Characteristic Length (LS-Dyna).
The available options are:
Program Controlled: Performs Automatic Node Movement for the Explicit Physics Preference. The value of the Physics Preference option sets the default for Program Controlled, as detailed in the following table:
Physics Preference Mechanical Nonlinear Mechanical Electromagnetics CFD Explicit Program Controlled Off Off Off Off On Conservative: Allows you to meet the target quality without moving the nodes away from the surface.
Aggressive: Allows you to move nodes outside the boundary to meet target mesh quality for a given Physics Preference. When you set Automatic Node Movement to Aggressive, you receive a warning message for node movement.
Custom: Allows you to customize the Feature Protection Angle, Restricted Node Movement to Surface, and Improvement Iterations to meet the target quality for given Physics Preference.
Restricted Node Movements to Surface: Allows you to constrain node movement to be only along the boundary when set to Yes. The default value is Yes for Custom and Conservative.
Improvement Iterations: Allows you to set the number of iterations performed by the algorithm to improve the target mesh quality. The default value is 3.
Feature Protection Angle: Specifies the minimum angle at which nodes move to meet target quality for given Physics Preference. After volumes are meshed, if the dihedral angle between two triangular element faces is less than the specified Feature Protection Angle, the nodes on the edge between the element faces are protected during Automatic Node Movement. The default value is 120 degrees for Custom and Conservative and 0 degrees for Aggressive. If the angle is set to 0 degrees, no nodes are protected during Automatic Node Movement.This is the most aggressive setting for quality improvement, causing nodes to locally move off features to attain quality targets where possible. If the angle is 180 degrees this effectively protects all nodes in the surface mesh from moving. That is, Automatic Node Movement would only acts only on interior nodes.
Refinement Options
Refine at Thin Section: Allows you the refine the number of element layers in the thin sections of the geometry when set to Yes. The default value is No.
Number of Element Layers: Provides the number of element layers in the thin section. Number of Element Layers is a read-only option. The default value is 2.
Refine Surface Mesh: Allows you to refine the surface mesh in the thin section of geometry when set to Yes. The default value is No. Refine Surface Mesh is available only when Use Adaptive Sizing is set to No.
Minimum Thickness: Allows you to set the minimum gap thickness to refine the surface mesh at thin sections with good quality elements. It is recommended to measure the thinnest section in your geometry and use this distance as input. The default value is half of the global Element Size.
Face Proximity Gap Factor: Allows you to refine or coarse the adjacent surface mesh.
Limitations
Automatic Node Movement does not support CFD Physics Preference.