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.
- 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 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 Hoe Tangent Offset of 3-Node Edge
CTETRA Default Bounds
Information | Default values for warning message | Default values for error message | Default values for validity check | |||
---|---|---|---|---|---|---|
Lower Limit | Upper Limit | Lower Limit | Upper Limit | Lower Limit | Upper Limit | |
Aspect Ratio | - | 100.0 | - | 1000.0 | - | 1.0E5 |
Face Skew Angle | - | 75.0 | - | 85.0 | - | 90.0 |
Collapse | 0.001 | 100.0 | 0.0 | 100.0 | 0.0 | 1000.0 |
Edge Angle (CTETRA4) | - | 75.0 | - | 87.0 | - | 90.0 |
Edge Angle (CTETRA10) | - | 75.0 | - | 90.0 | - | 90.0 |
Hoe Normal Offset | - | 0.30 | - | 0.60 | - | 1.0E5 |
Hoe Tangent Offset | - | 0.20 | - | 0.25 | - | 0.50 |
The values used for warning and error checks may be adjusted by the ELEMQUAL Bulk Data Entry, but validity checks are hard-coded.