SED, SEDX, SEDY, SEDZ, Cname
Defines the excitation direction for response spectrum
and PSD analyses.
SEDX, SEDY, SEDZGlobal Cartesian coordinates of a point that defines a line (through the origin) corresponding to the excitation direction. For example: 0.0, 1.0, 0.0 defines global Y as the spectrum direction.
CnameThe component name corresponding to the group of excited nodes. Only applies to base excitation multi-point response spectrum analysis (SPOPT, MPRS) and power spectral density analysis (SPOPT, PSD). Defaults to no component.
In single-point response spectrum analysis (SPOPT,SPRS), the excitation
direction without rocking (ROCK) is normalized to one so that the
SEDX, SEDY, and
SEDZ values do not scale the spectrum. The excitation direction with
rocking is not normalized. The SEDX, SEDY,
and SEDZ values must be consistent with the linear components of
OMX, OMY, and
OMZ values on the ROCK command. The calculated
direction then scales the spectrum. For more information, see Participation Factors and Mode Coefficients.
In multi-point response spectrum analysis
(SPOPT,MPRS) and power spectral density analysis
(SPOPT,PSD), the excitation direction is normalized
to one so that the SEDX, SEDY, and SEDZ values do not scale the spectrum.
The component name (Cname) is required.
The constraints corresponding to the excitation direction are applied
to the component nodes.
This command is also valid in PREP7.