VISCO
Bulk Data Entry Defines parameters for nonlinear analysis involving time-dependent material behavior.
Format
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| VISCO | ID | CETOL | TINT |
Example
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| VISCO | 2 |
Definitions
| Field | Contents | SI Unit Example |
|---|---|---|
| ID | Each
VISCO Bulk Data card must have a unique
ID. No default (Integer > 0) |
|
| CETOL | Tolerance for viscoelastic
time integration. Ensures that the viscoelastic/creep strain
increment is controlled by the specified tolerance. If not specified or zero, fixed time integration will be used. No default (Real ≥ 0) 2 |
|
| TINT | Numerical time integration
scheme for solving creep equations. 3
|
Comments
- The VISCO Bulk Data entry can be referenced in the subcase section to specify if viscoelasticity/creep analysis is activated in that subcase.
- CETOL is the
tolerance to control the time increment size.
- It ensures the viscoelastic/creep strain increment is controlled by the specified tolerance.
- In situations where stress significantly affects the creep strain rate, one way to estimate CETOL is to set it equal to an acceptable error in stress divided by a representative elastic modulus.
- Currently, CETOL is only supported for Small Displacement Nonlinear Analysis (SMDISP).
- Creep problems are often solved efficiently by the explicit integration method. This is computationally efficient because, unlike implicit methods, iterations are not required. However, the explicit method is conditionally stable, due to the maximum time step size limitations.