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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

Prepro: COQJ4A.F
Lagamine: COQJ4B.F

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