CTETRA Element Checks and Default Bound Values

CTETRA 1st-order (4-noded) Element Checks

The following qualities of the CTETRA 1st-order element are checked:

·        Aspect Ratio

The aspect ratio of a CTETRA 1st-order element is defined as the maximum of the aspect ratio of its four triangular faces. Each face is treated as a CTRIA3 element.

·        Face Skew Angle

The face skew angle of a CTETRA 1st-order element is defined as the maximum of the skew angles of its four triangular faces. Each face is treated as a CTRIA3 element.

·        Vertex Angle

The same vertex angle check is performed for all of the faces, and each is treated as a triangular (CTRIA3) or quadrilateral (CQUAD4) element. The minimum and maximum values reported for the element.

·        Collapse

The collapse of a CTETRA 1st-order element is defined as the minimum of four values, each calculated as the ratio between the distance from a vertex to its opposing face, and the square root of the area of the opposing face.

The reported value is normalized by 1.2408, which gives the equilateral tetra a collapse value of 1. As the tetra collapses, the collapse value approaches 0.

·        Edge Angle

An edge angle is the absolute value of the angle between two faces sharing a common edge subtracted from 90 degrees. The edge angle (EA) of a CTETRA 1st-order element is defined as the maximum of its six edge angles.

CTETRA 2nd-order (10-noded) Element Checks

The following qualities of the CTETRA 2nd-order element are checked:

·        Aspect Ratio

This quality is calculated using only the corner nodes. Its definition is the same as that used for the CTETRA 1st-order element.

·        Face Skew Angle

This quality is calculated using only the corner nodes. Its definition is the same as that used for the CTETRA 1st-order element.

·        Vertex Angle

This quality is calculated using only the corner nodes. Its definition is the same as that used for the CTETRA 1st-order element.

·        Collapse

This quality is calculated using only the corner nodes. Its definition is the same as that used for the CTETRA 1st-order element.

·        Edge Angle

This quality is calculated using only the corner nodes. Its definition is the same as that used for the CTETRA 1st-order element.

·        Hoe Normal Offset

The hoe normal and tangent offsets of the CTETRA 2nd-order element are defined as the maximum of the hoe normal and tangent offsets of its 6 edges, respectively. See the definition of hoe normal offset of 3-node edge.

·        Hoe Tangent Offset

The hoe normal and tangent offsets of the CTETRA 2nd-order element are defined as the maximum of the hoe normal and tangent offsets of its 6 edges, respectively. See definition of hoe tangent offset of 3-node edge.

CTETRA Default Bounds

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Element Quality Check