Table of Contents
COQJ4
Quadrangular shallow shell element
Description
- Bending: Kirchhoff's theory in plane stress state
- Corotational total Lagrangian formulation taking into account the curvature of the element during deformation (Marguerre theory is used in cartesian coordinates; the element converges towards a deep shell solution).
- Plastic part computed using Green deformations (+ Piola-Kirchhoff stress) and elastic part computed with real deformation (+ Cauchy stress) ⇒ the elastic part must be negligible compared to the plastic part.
- 4 nodes with 6 DoF each: 3 translations and 3 rotations
- 2*2 Gauss integration points
- Contact or uniform loading can be taken into account
Type: 45
Imported from FINELG by Li Kaiping in 1991
Files
Prepro: COQJ4A.F
Lagamine: COQJ4B.F
Input file
| Title (A5) | |
|---|---|
| TITLE | “COQJ4” in the first 5 columns |
| Control data (3I5) | |
| NELEM | Number of elements |
| ILOC | Index for actualization of local axes = 0 → New approach (Recommanded default value) = 1 → Old approach (problem with step size) |
| INDPP | = 0 → No specific density (Static analysis: NTANA > 0) = 1 → Specific density taken into account (Dynamic analysis: NTANA < 0) |
| Density - only if INDPP = 1 (dynamic analysis only) (2G10.0) | |
| WSPE(4) | Density |
| DMASS_ROT | Multiplicative factor for masses in rotation (default value =1) |
| Definition of the shell elements (2I5, G10.0) | |
| LMATE | Material law |
| NELMC | Number of elements of contact/loading associated with the shell element (0 ≤ NELMC ≤ 5) |
| THICK | Initial thickness of the shell |
| Definition of the contact/load elements (4I5) - NELMC times | |
| NPI | Number of integration points for contact/loading (4 or 9) |
| IMAT | Material law for contact/loading |
| IFUND | Number of the foundation to contact > 0 there will be contact on the upper surface of the shell < 0 there will be contact on the lower surface of the shell |
| IRIGF | Type of contact (same meaning as CFI3D): = 0 → foundation or rigid tool (by default) = 1 → uncoupled structure/structure contact = 2 → coupled structure/structure contact = 3 → coupled structure/structure contact = 4 → coupled structure/structure contact - pilot node |
| List of nodes of the shell element (8I5) | |
| NODES(I) I=1,4 | Corner nodes |
| NODESM(I) I=1,4 | [OPTIONAL] Nodes of the middle of the sides (A to D), used only to define the initial geometry of the element. These nodes must be fixed along the 6 DoF. If they are not given, they are computed automatically and placed at the middle of each side. |
Remark
It is not possible to take into account the specific weight in static analysis
Results
For each integration point:
- Stresses (see material law)
- State variable:
- Q(1→NVMAX): see material law
- Q(NVMAX+1): $e_{xM}$
- Q(NVMAX+2): $e_{yM}$
- Q(NVMAX+3): $e_{zM}$
- Q(NVMAX+4): $e_{xF}$
- Q(NVMAX+5): $e_{yF}$
- Q(NVMAX+6): $e_{zF}$
- If there are contact elements (see law):
- Stresses of the contact element
- State variables of the contact elements
State variables of the additional solid element (not printable in the .out file):
- Local coordinates
- Rotation matrix to change to the local frame