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elements:ssh3d
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Table of Contents
SSH3D
Description
8 node large strain shell element. The
Enhanced Assumed Strain (EAS) technique based on the Hu-Washizu variational principle is used
to cure the volumetric locking occurring when the material shows nearly incompressible behavior and Poisson’s thickness locking caused by the high aspect ratio of the finite element
Implemented by: Amine Ben Bettaieb, December 2009
Type: 23
Prepro: SSH3DA.F
Lagamine: SSH3DB.F
Input file
| TITLE (A5) | |
|---|---|
| TITLE | 'SSH3D' en colonnes 1 à 5 |
| CONTROL (4I5) | |
| NELEM | Nombre d'éléments |
| NEAS | Nombre de modes EAS (Enhanced Assumed Strain) compris entre 1 et 30 |
| ILOAX | Calcul avec les axes locaux |
| =1 if shear coefficient taken into account | |
| =-1 for use of element BWD3D (only 1 integration point) | |
| ILOAX | =0 for global axis computation ☛ Objectivity must be verified in the material law ☛ No rotation of material axes |
| <0 for computation with constant and symetrical velocity gradients pseudo local axes : use of local axes on the time step but no evolution of the local axes on the following time step ☛ Objectivity is verified ☛ No rotation of material axes |
|
| >0 for computation with local axes ☛ Objectivity is verified ☛ Rotation of material axes |
|
| units: = 1 for rotations incorporated in local tangent matrix  Not available = 2 apply final rotation to local tangent matrix = 3 apply initial rotation to local tangent matrix = 4 compute tangent matrix through global perturbation method |
|
| tens (only for ILOAX>0): = 0 for local axes e1, e2, e3 initially parallel to global axes ex, ey, ez = 1 for local axes e1, e2 given (and e3=e1∧e2) = 2 for local axes e1, e2 initially in the plane (ex, ey) forming an angle θ with ex, ey = 3 same as 1 with different local axes for each element = 4 same as 2 with different local axes for each element |
|
| ISIG0 | = 0 if no initial stresses |
| = 1 for input of initial stresses | |
| CONSIDERATION OF WEIGHT (4G10.0) Only if INDPP = 1 |
|
| WSPE(1) | = specific weight in X direction |
| WSPE(2) | = specific weight in Y direction |
| WSPE(3) | = specific weight in Z direction |
| WSPE(4) | = density |
| CONSIDERATION OF SHEAR LOCKING (1G10.0) Only if INSHE = 1 |
|
| PARSHE | Shear locking coefficient ∈ [0,1] - close to 0: avoid shear locking but higher risk of hourglass modes (use for thin elements in flexion) - close to 1: avoid hourglass modes but higher risk of shear locking (use for cubic elements in shear) |
| INITIAL ORIENTATION OF LOCAL AXES (6G10.0) Only if tens of ILOAX = 1 or 3 |
|
| e1(x) | coordinate of e1 along ex |
| e1(y) | coordinate of e1 along ey |
| e1(z) | coordinate of e1 along ez |
| e2(x) | coordinate of e2 along ex |
| e2(y) | coordinate of e2 along ey |
| e2(z) | coordinate of e2 along ez |
| Note: These vectors are normalized after reading but should be orthogonal: e1 • e2 = e1(x) * e2(x) + e1(y) * e2(y) + e1(z) * e2(z) = 0 |
|
| INITIAL ORIENTATION OF LOCAL AXES (1G10.0) Only if tens of ILOAX = 2 or 4 |
|
| THETA | Angle between e1 and ex in degrees |
| DEFINITION OF THE ELEMENTS (2I5/8I5/6G10) | |
| NINTE | Number of integration points (1, 2, 4 or 8) if NINTE = 1, add 40 to MVARI compared to maximum required by laws |
| LMATE | Number of the material law |
| NODES(8) | List of nodes |
| SIG0(6) | List of initial stresses (Only if ISIG0=1) |
elements/ssh3d.1553617549.txt.gz · Last modified: 2020/08/25 15:34 (external edit)
