XSHLPRM

Bulk Data Entry Defines default shell element parameters for geometric nonlinear analysis.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
XSHLPRM I I I I I NIP I    

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
XSHLPRM 24   2   NEWT 5      

Definitions

Field Contents SI Unit Example
I 4-node shell element formulation flag.
1
Q4, visco-elastic hourglass modes orthogonal to deformation and rigid modes (Belytschko).
2
Q4, visco-elastic hourglass without orthogonality (Hallquist). Is incompatible with one integration point for shell element.
3
Q4, elastic-plastic hourglass with orthogonality.
4
Q4 with improved type 1 formulation (orthogonalization for warped elements).
12
QBAT or DKT18 shell formulation.
24 (Default)
QEPH shell formulation.

(Integer)

  
I 3-node shell element formulation flag.
1
Standard triangle (C0).
2 (Default)
Standard triangle (C0) with modification for large rotation.
30
DKT18.
31
DKT_S3.

(Integer)

  
I Shell small strain formulation flag.
1
Small strain from time =0 (new formulation compatible with all other formulation flags).
2 (Default)
Full geometric non-linearity with optional small strain formulation activation by time step.
3
Old small strain formulation (only compatible with ISHELL=2).
4
Full geometric non-linearity (Time step limit has no effect).

(Integer)

  
I Shell resultant stresses calculation flag.
CONST
Thickness is constant.
VAR (Default)
Thickness change is taken into account. Recommended to use IPLAS=NEWT.
  
I Shell plane stress plasticity flag (MATX2, MATX27, and MATX36 only).
RAD
Radial return.
NEWT (Default)
Iterative projection with 3 Newton iterations.
  
NIP Number of integration points through the thickness.
= 0
Defines global integration and is only compatible with MAT1, MATX2, and MATX36.

Default = 5 (Integer 0 ≤ N ≤ 10)

  
I Drilling degree of freedom stiffness flag.
0 (Default)
No
1
Yes

(Integer)

  

Comments

  1. XSHLPRM defines default settings for shell properties that can be overwritten by PSHELLX.
  2. XSHLPRM is only applied in geometric nonlinear analysis subcases which are defined by ANALYSIS=EXPDYN. It is ignored for all other subcases.
  3. Q4: Original 4 node OptiStruct shell with hourglass perturbation stabilization.
  4. QEPH: Formulation with physical hourglass stabilization for general use.
  5. QBAT: Modified BATOZ Q4 γ 24 shell with 4 Gauss integration points and reduced integration for in-plane shear. No hourglass control is needed for this shell.
  6. DKT18: BATOZ DKT18 thin shell with 3 Hammer integration points.
  7. If the small strain option (I) is set to 1 or 3, the strain and stress are engineering strain and stress; otherwise they are true strain and stress.
  8. For MAT1, membrane only behavior happens if NIP=1. Otherwise, NIP is ignored and global integration (NIP=0) is used.
  9. For MATX2, the default value for I and global integration (NIP=0) is I=RAD.
  10. For MATX36, the default value for I and global integration (NIP=0) is I=NEWT.
  11. This card is represented as a control card in HyperMesh.