Two-Way Radio User Manual

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STEADY STAT E DYNAMICS
Set SUBSPACE PROJECTION=EIGENFREQUEN CY if the projections onto the modal
subspace of the dynamic equations are to be performed at each eigenfrequency within the
requested ranges and at the eigenfrequencies immediately outside these ranges. The projections
are then interpolated at each frequency requested on the data lines. The interpolation is done on a
logarithmic or linear scale depending on the value of the FREQUENCY SCALE param eter. This
value cannot be used for coupled acoustic-structural analysis.
Set SUBSPACE PROJECTION=PROPERTY CHANGE to select how often subspace
projections onto the modal subspace are performed based on m aterial property changes as a
function of frequency. The interpolation is done on a logarithmic or linear scale depending
on the value of the FREQUENCY SCALE parameter. This value cannot be used for coupled
acoustic-structural analysis.
Optional parameters:
FREQUENCY SCALE
Set this parameter equal to LOGARITHMIC (default) or LINEAR to determine whether a
logarithmic or linear scale is used for output. If the SUBSPACE PROJECTION param eter is
included and is set equal to either EIGENFREQUENCY or PROPERTY CH ANG E, the same scale
will be used for the interpolation of the subspace projections.
INTERVAL
Set INTERVAL=EIGENFREQUENCY if the frequency ranges specified on each data line are to be
subdivided using the system’s eigenfrequencies. This option requires a preceding
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FREQUENCY
step and is the default if the DIRECT parameter is omitted.
Set INTERVAL=RANGE if the frequency range specified on each data line is to be used
directly. This option is the default if the DIRECT parameter is included.
REAL ONLY
This param eter is relevant only if the DIRECT or the SUBSPACE PRO JECTION parameter is
included. Include this parameter if dampi ng terms are to be ignored so that a rea l, rather than a
complex, system matrix is factored. This option can reduce computational time significantly for the
DIRECT procedure and, to a lesser extent, for the SUBSPACE PROJECTION procedure.
Optional parameters for SUBSPACE PROJECTION=PROPERTY CHANGE:
DAMPING CHANGE
Set this parameter equal to the m axim um relative change in damping m aterial properties before a
new projection is to be performed. The default value is 0.1.
STIFFNESS CHAN GE
Set this parameter equal to the maximum relative change in stiffness material properties before a
new projection is to be performed. The default value is 0.1.
18.34–2
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