ABAQUS Keywords Reference Manual  

*SPECTRUM
Define a response spectrum.

This option is used to define a spectrum to be used in a *RESPONSE SPECTRUM analysis.

Product: ABAQUS/Standard  

Type: Model data

Level: Model  

References:

Required parameter:

NAME

Set this parameter equal to the name that identifies the spectrum. This name is used to cross-reference a spectrum on the *RESPONSE SPECTRUM option.

Optional parameters:

G

Set this parameter equal to the value of the acceleration of gravity. This parameter is used only when TYPE=G is specified.

INPUT

Set this parameter equal to the name of the alternate input file containing the data lines for this option. See “Input syntax rules,” Section 1.2.1 of the ABAQUS Analysis User's Manual, for the syntax of such file names. If this parameter is omitted, it is assumed that the data follow the keyword line.

TYPE

Set TYPE=DISPLACEMENT, TYPE=VELOCITY, or TYPE=ACCELERATION (default) to define the units in which the spectrum is defined.

Set TYPE=G to enter an acceleration spectrum in -units. The parameter G then defines the gravitational acceleration.

Date lines to define a spectrum: 

First line:

  1. Magnitude of the spectrum.

  2. Frequency, in cycles per time, at which this magnitude is used.

  3. Associated damping, given as ratio of critical damping.

Repeat this data line as often as necessary to define the spectrum at all frequencies at each damping value.