ABAQUS Volume II: I–Z - Manual (Page 436)

*SOILS
FACTOR
Set this parameter equal to the damping factor to be used in the automatic damping algorithm
(see “Solving nonlinear problems,” Section 7.1.1 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.
STABILIZE
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 7.1.1 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.
UTOL
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).
Data line to define incrementation for a soils analysis:
First (and only) line:
1. 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.
2. Time period. If END=SS is chosen, the step ends after this time period or when steady-state
conditions are reached, whichever comes first.
3. 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.
4. Maximum time increment allowed. If this value is not specified, the upper limit is the total
time period. Only used for automatic time incrementation.
18.21–2
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