This option is used to specify transient (consolidation) or steady-state response analysis of partially or fully saturated fluid-filled porous media.
Product: ABAQUS/Standard
Type: History data
Level: Step
This parameter will invoke automatic time incrementation. If both the UTOL and CETOL parameters are omitted, fixed time increments will be used.
This parameter is meaningful only when the material response includes time-dependent creep behavior; CETOL controls the accuracy of the creep integration. Set this parameter equal to the maximum allowable difference in the creep strain increment calculated from the creep strain rates at the beginning and at the end of the increment (see “Rate-dependent plasticity: creep and swelling,” Section 11.2.4 of the ABAQUS Analysis User's Manual).
The tolerance can be calculated by choosing an acceptable stress error tolerance and dividing by a typical elastic modulus.
Include this parameter to choose transient (consolidation) analysis. Omit this parameter to choose steady-state analysis.
This parameter is meaningful only for transient analysis. Set END=PERIOD (default) to analyze a specified time period. Set END=SS to end the step when steady state is reached.
Set CREEP=NONE to specify that there is no creep or viscoelastic response occurring during this step even if creep or viscoelastic material properties have been defined.
Set this parameter equal to the damping factor to be used in the automatic damping algorithm (see “Solving nonlinear problems,” Section 8.2.1 of the ABAQUS Analysis User's Manual) if the problem is expected to be unstable due to local instabilities and the damping factor calculated by ABAQUS/Standard is not suitable. This parameter must be used in conjunction with the STABILIZE and CONSOLIDATION parameters and overrides the automatic calculation of the damping factor based on a value of the dissipated energy fraction.
Include this parameter to use automatic stabilization if the problem is expected to be unstable due to local instabilities. Set this parameter equal to the dissipated energy fraction of the automatic damping algorithm (see “Solving nonlinear problems,” Section 8.2.1 of the ABAQUS Analysis User's Manual). If this parameter is omitted, the stabilization algorithm is not activated. If this parameter is included without a specified value, the default value of the dissipated energy fraction is 2 × 10–4. If the FACTOR parameter is used, any value of the dissipated energy fraction will be overridden by the damping factor.
This parameter can be used only in conjunction with the CONSOLIDATION parameter.
This parameter will invoke automatic time incrementation. If both the UTOL and the CETOL parameters are omitted, fixed time increments will be used.
Set this parameter equal to the maximum pore pressure change permitted in any increment (in pressure units) in a transient consolidation analysis. ABAQUS/Standard will restrict the time step to ensure that this value will not be exceeded at any node (except nodes with boundary conditions) during any increment of the analysis.
Set this value equal to any nonzero value in a steady-state analysis (to activate automatic time incrementation).
First (and only) line:
Initial time increment. This value will be modified as required if the automatic time stepping scheme is used; it will be used as a constant time increment otherwise.
Time period. If END=SS is chosen, the step ends after this time period or when steady-state conditions are reached, whichever comes first.
Minimum time increment allowed. If ABAQUS/Standard finds it needs a smaller time increment than this value, the analysis is terminated. If this entry is zero, a default value of the smaller of the suggested initial time increment or 10–5 times the total time period is assumed. Only used for automatic time incrementation.
Maximum time increment allowed. If this value is not specified, the upper limit is the total time period. Only used for automatic time incrementation.
The rate of change of pore pressure with time, used to define steady state: only needed if END=SS is chosen. When all nodal wetting liquid pressures are changing at rates below this value, the solution terminates.