Description
The CQUADR entry defines a quadrilateral element that can be used as a membrane or shell. A shell element has bending stiffness while the membrane element does not. For both the membrane and shell formulations, the state of the stress in the element is plane stress. The elements do have strains through the thickness of the element, which will lead to thinning of the element.
Format
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| CQUADR | EID | PID | G1 | G2 | G3 | G4 | THETA/MCID |
Example
| CQUADR | 61 | 11 | 101 | 111 | 201 | 202 |
| Field | Definition | Type | Default |
|---|---|---|---|
| EID | Element identification number. | Integer > 0 | Required |
| PID | Property identification number of a PSHELL or PCOMP property entry. | Integer > 0 | Required |
| Gi | Grid point identification numbers of connection points. | Integer > 0, all unique | Required |
| THETA | Material property orientation angle in degrees. | Real | |
| MCID | Material coordinate system identification number. | Integer ≥ 0 | See Remark 7 |
Remarks
- Element identification numbers must be unique with respect to all other element identification numbers.
- Grid points G1 through G4 must be ordered consecutively around the perimeter of the element.
- All the interior angles must be less than 180 degrees.
- Components of stress are output in the surface coordinate system unless THETA or MCID are used to define a local coordinate system.
- The rotational degrees of freedom at the connection points and normal to the element are active in the element formulation and must not be constrained unless at a boundary.
- This element is identical to the CQUAD4 element.
- If THETA/MCID field is blank, field 5 of the PSHELL continuation entry will be used. If this field is also blank, then THETA = 0.0 is assumed.
Figure 1: MCID coordinate system definition
Figure 2: CQUADR element geometry and coordinate system
Figure 3a: Forces in CQUADR elements
Figure 3b: Moments in CQUADR elements
Figure 4: Stresses in CQUADR elements