*STEADY STATE DYNAMICS
18.34 *STEADY STATE DYNAMICS: Steady-state dynamic response based on harmonic
excitation.
This option is used to calculatethe system ’slinearized steady-state response to harmonic excitation.
Product: ABAQUS/Standard
Type: History data
Level: Step
References:
•“Direct-solutionsteady-state dynamic analysis,” Section 6.3.4 of the ABAQUS Analysis User’s Manual
•“Mode-based steady-state dynamic analysis,” Section6.3.8 of the ABAQUS Analysis User’s Manual
•“Subspace-basedsteady-state dynamic analysis,” Section 6.3.9 of the ABAQUS Analysis User’s Manual
Optional and mutually exclusiveparameters (used only if the dynamic response is not based
on modal superposition):
DIRECT
Include this parameter to compute the steady-state harmonic response directly in terms of the
physical degrees of freedom of the model. This usually makes the procedure significantly more
expensive, but it can be used if model param eters depend on frequency, if the stiffness of the
system is unsymmetric and the unsymmetric ter ms are important, or if the system contains discrete
damping (such as dashpot elements).
SUBSPACE PROJECTION
Include this parameter to compute the steady-stateharmonic response on the basis of the subspace
projection method. In this case a direct solution is obtained for the model projected onto the
eigenvectors obtained in the preceding *FREQUENCY step. This is a cost-effective approach to
including considerationof unsymm etricstiffness and frequency-dependent model parameters. Itis
more expensive than the modal superposition method but less exp ensive than the direct-solution
method.
Set SUBSPACE PROJECTION=ALL FREQUENCIES (default) if the projection of the
dynamic equations onto the modal subspace is to be performed at eachfrequency requested on the
data lines.
Set SUBSPACEPROJECTION=CONSTANT if a single projection of the dynamic equations
onto them odalsubspace is to be used for all frequencies requested on the data lines. The projection
is performed using model properties evaluatedat the center frequency determined on a logarithmic
or linear scale dependingon the value of the FREQUENCY SCALE parameter. This value cannot
be used for coupled acoustic-structural analysis.
18.34–1
ABAQUS Version 6.1 Module: ID:
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