Table of Contents
BLZ3D/BWD3D
Description
8 node large strain volumetric element with hourglass and locking control.
Implemented by: Zhu Yongyi, January 1992
Improved by: Laurent Duchêne and Pierre de Montleau, August 2004 (BWD3D version)
Type: 22
Prepro: BLZ3DA.F
Lagamine: BLZ3DB.F, BWD3DB.F
Input file
| TITLE (A5) | |
|---|---|
| TITLE | 'BLZ3D' in columns 1 to 5 |
| CONTROL (5I5) | |
| NELEM | Number of elements |
| INDPP | = 0 if no weight (or no density if NTANA=-1) |
| = 1 if weight taken into account (or density) | |
| INSHE | = 0 for automatic calculation of shear locking parameter |
| = 1 if shear coefficient taken into account (see below) | |
| = -1 for use of element BWD3D (only 1 integration point) | |
| ILOAX | = 0 for global axis computation ☛ Objectivity must be verified in the material law (with Jaumann correction) ☛ 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 (and e3=e1∧e2) = 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 (only one line if tens of ILOAX = 1, repeated for each element if tens of ILOAX = 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 (only one line if tens of ILOAX = 2, repeated for each element if tens of ILOAX = 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) |