Users:General FEM Analysis/Elements Reference/Shell9

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* NONE: ANS is not activated
 
* NONE: ANS is not activated
 
* Q: ANS against shear locking is activated. It works for 4-noded and 9-noded elements. It causes a constant-linear (linear-quadratic, respectively) interpolation of the transverse shear strains and thus avoids transverse shear locking. The approach for the 4-noded element represents the well-known Bathe-Dvorkin-Element (MITC-4).
 
* Q: ANS against shear locking is activated. It works for 4-noded and 9-noded elements. It causes a constant-linear (linear-quadratic, respectively) interpolation of the transverse shear strains and thus avoids transverse shear locking. The approach for the 4-noded element represents the well-known Bathe-Dvorkin-Element (MITC-4).
−
* T: ANS against curvature thickness locking {{Template:UnderDevelopment|Michi|08/2010}}
+
* T: ANS against curvature thickness locking
 
|-
 
|-
 
!EAS
 
!EAS
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!FORCE
 
!FORCE
 
|XYZ, RST_ORTHO, RST
 
|XYZ, RST_ORTHO, RST
−
|Output control for stress constraints {{Template:UnderDevelopment|Michi, Matthias|08/2010}}
+
|Output control for stress constraints
 
* XYZ:  
 
* XYZ:  
 
* RST_ORTHO:  
 
* RST_ORTHO:  
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=== Example of a Complete Input Block ===
 
=== Example of a Complete Input Block ===
 
<pre>
 
<pre>
−
EL-PROP 1 : SHELL8
+
EL-PROP 1: SHELL9
−
MAT=EL-MAT 1      
+
MAT=EL-MAT 1  
−
THICKNESS=0.1  
+
THICKNESS = 0.1
−
INT_TYPE_SHELL8 = FULL
+
INT_TYPE_SHELL9 = FULL
−
SDC= 1.0
+
SDC = 1.0
−
EAS = 4,4,4,0,4  
+
EAS = 4,4,4,4,4
−
ANS = Q
+
ANS = NONE
−
FORCE = RST_ORTHO
+
FORCE = XYZ
 +
MATERIAL_ANGLE = 0
 +
 
 +
ROTATORIC_DOFS = DIR_DIFF
 +
STRESS_OUTPUT = PRIN_VM
 +
STRESS_EVAL  = SURF 
 
</pre>
 
</pre>
 +
 +
== Benchmarks ==
 +
 +
The main benchmark files in the ''Carat++''-repository are
 +
 +
'../examples/benchmark_examples/elements/shell9_4_temperature_nln/cbm_SHELL_4NODED.dat'
 +
 +
'../examples/benchmark_examples/elements/shell9_8_temperature_nln/cbm_SHELL_8NODED.dat'
 +
 +
== Known issues ==
 +
 +
Eigenvalue analysis with DIR_DIFF gives wrong results (AE, SSH;2017)

Latest revision as of 12:16, 12 April 2017

The element formulation is based on the Shell8.

Contents

Input Parameters

Parameter Description

Compulsory Parameters
Parameter Values, Default(*) Description
MAT EL-MAT int Linking to a material input block
INT_TYPE_SHELL9 FULL Control of integration type
ANS NONE, Q, T, QT, TQ Assumed Natural Strains (ANS) method:
  • NONE: ANS is not activated
  • Q: ANS against shear locking is activated. It works for 4-noded and 9-noded elements. It causes a constant-linear (linear-quadratic, respectively) interpolation of the transverse shear strains and thus avoids transverse shear locking. The approach for the 4-noded element represents the well-known Bathe-Dvorkin-Element (MITC-4).
  • T: ANS against curvature thickness locking
EAS M,B,T,Q,S Enhances Assumed Strains (EAS) method
  • M: Number of enhanced membrane modes. M = {1,(2),4,5,7} for 4-noded Elements, M = {(7),9,11} for 8- or 9-noded Elements
  • B: Number of enhanced bending modes. B = {4,5,(6),7} for 4-noded Elements, B = {9,11} for 8- or 9-noded Elements
  • T: Number of enhanced modes in thickness direction. T = {1,3,4,6,8,9} for all Elements. Recommended: 1 (3-noded), 4 (4-, 8- and 9-noded), 3 (6-nonded)
  • Q: Number of const. transverse shear modes. Q = {2,4} for 4-noded Elements, Q = {2,4,6} for 8- or 9-noded Elements
  • S: Number of lin. transverse shear modes. S = {2,4} for 4-noded Elements, S = {2,4,6} for 8- or 9-noded Elements
FORCE XYZ, RST_ORTHO, RST Output control for stress constraints
  • XYZ:
  • RST_ORTHO:
  • RST:
SDC real condition factor for director length, recommended value: 1.0
ROTATORIC_DOFS DIR_DIFF, GLOB_6 Switch between director and rotational degrees of freedom.
STRESS_OUTPUT PRIN_VM, SIG_EPS Stress output type
  • PRIN_VM: Von Mises Stresses
  • SIG_EPS: Stress and strains
STRESS_EVAL GP, SURF Stress evaluation location.
  • Gauss Point
  • Surface
Optional Parameters
Parameter Values, Default(*) Description
THICKNESS real Element thickness. This parameter is not compulsory, as the thickness can also be described via nodal values.


Example of a Complete Input Block 

EL-PROP 1: SHELL9
MAT=EL-MAT 1 
THICKNESS = 0.1
INT_TYPE_SHELL9 = FULL
SDC = 1.0
EAS = 4,4,4,4,4
ANS = NONE
FORCE = XYZ
MATERIAL_ANGLE = 0

ROTATORIC_DOFS = DIR_DIFF
STRESS_OUTPUT = PRIN_VM 
STRESS_EVAL   = SURF

Benchmarks

The main benchmark files in the Carat++-repository are

'../examples/benchmark_examples/elements/shell9_4_temperature_nln/cbm_SHELL_4NODED.dat'

'../examples/benchmark_examples/elements/shell9_8_temperature_nln/cbm_SHELL_8NODED.dat'

Known issues

Eigenvalue analysis with DIR_DIFF gives wrong results (AE, SSH;2017)





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