3D Connexion Version 6.6

*STEP

CONVERT SDI

This parameter determines how severe discontinuities (such as contactchanges) are accounted for

during nonlinear analysis.

SetCON VERTSDI=NO (d efault) to force a new iteration if severe discontinuities occur during

an iteration.

Set CONVERT SDI=YES to estimate residual forces associated with severe discontinuities

and check whether the equilibrium tolerancesare satisﬁed. Hence, a solution may converge if the

severe discontinuties (such as penetrations or tensile contact forces) are small. This option also

changes some time incrementation parameters and uses different criteria to determine whetherto

do another iteration or tom ake a new attempt witha sm allerincrem entsize.

Ifthe CONVERT SDI parameter is omitted, ABAQUS/Standard will use the value speciﬁed in

the previousgeneral analysis step. Thedefault can be changed with the environment and command

line variable convert_sdi.

This parameter has no relevance and will be ignored for heat transfer analysis and linear

perturbation steps.

DSA

This parameter applies only to ABAQUS/Design.

Set DSA=YES to activate design sensitivity analysisfor the step. OnceDSA is activated in a

general step, it remains active in all subsequent general steps untilit is deactivated in a subseque nt

general step by setting DSA=NO. Once DSA is activated in a perturbationstep, it remains active

in all subsequent consecutive perturbationsteps until it is deactivated in a subsequent consecutive

perturbation step. However, if DSA is activated in a step whose procedure is not supported for

DSA, DSA will be deactivated until it is activated again by settingDSA=YES.

EXTRAPOLATION

This parameter is useful only for nonlinear analyses.

Set EXTRAPOLATION=LINEAR (default) to indicate that the process is essentially

monotonic, so that ABAQUS/Standard should use a 100% linear extrapolation, in time, of the

previous incremental solution tobegin the nonlinear equation solution for the current increment (a

1% extrapolation is used with the Riks method).

Set EXTRAPOLATION=PARABOLIC to indicate that the process should use a quadratic

extrapolation, in time, of the previous two incremental solut ions to begin the nonlinear equation

solution for the current increment.

Set EXTRAPOLATION=NO(not available for dynamic or Riks method analyses) to suppress

any extrapolation.

INC

Set this parameter equal to the maximum number of inc rements in a step (or in a single loading

cycle for direct cyclic analysis). This value is only an upper bound. The default value is 100.

TheINC parameter has no effect in procedures where automatic incrementation cannot be used

(for example, *BUCKLE, *STEADY STATEDYNAMICS, and *MODAL DYNAMIC).

18.36–2

ABAQUS Version 6.1 Module: ID:

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