CTRIA3 Element Checks and Default Bound Values
CTRIA3 Element Check
The following qualities of the CTRIA3 element are
checked:
- Aspect Ratio
- The aspect ratio of a CTRIA3 element is defined as the ratio of the maximum side length to the minimum side length.
- Skew Angle
- The skew angle of a CTRIA3 element is the difference between 90 degrees and the minimum of three angles: a1, a2 and a3. These angles are defined, for the CTRIA3 element, as the smallest of the angles created when a line drawn from a node to the midpoint of the opposing side intersects a line connecting the midpoints of the adjacent two sides. The skew angle has a range from 0 degrees for a perfect triangle to 90 degrees for a collapsed triangle.
- SKEW = 90 - MIN(a1, a2,
a2)
Figure 1. - Vertex Angle
- For each vertex, the angle is measured between its two adjacent edges. The minimum and maximum values of the three nodes are reported for the element.
CTRIA3 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 | - | 50.0 | - | 500.0 | - | 1.0E5 |
| Skew Angle | - | 75.0 | - | 85.0 | - | 90.0 |
| Vertex Angle | 15.0 | 165.0 | 3.0 | 177.0 | 0.0 | 180.0 |
The values used for warning and error checks may be adjusted by the ELEMQUAL Bulk Data Entry, but validity checks are hard-coded.