Abaqus Keywords Reference Manual  

*SELECT EIGENMODES
Select the modes to be used in a modal dynamic analysis.

This option selects the modes to be used in a dynamic analysis based on modes or in a complex eigenvalue extraction analysis. Only one option per step can be used. If this option is not used, all modes extracted in the prior *FREQUENCY step will be used, including residual modes if they were activated.

Product: Abaqus/Standard  

Type: History data

Level: Step

References:

Optional parameters:

DEFINITION

Set DEFINITION=MODE NUMBERS (default) to indicate that the selected modes are given as a collection of mode numbers.

Set DEFINITION= FREQUENCY RANGE to indicate that the modes are selected from the specified frequency ranges including frequency boundaries. Frequency ranges can be discontinuous.

If both the *MODAL DAMPING and *SELECT EIGENMODES options are used in the same step, the DEFINITION parameter must be set equal to the same value in both options.

GENERATE

If this parameter is included, each data line should give a first mode, ; a last mode, ; and the increment in mode numbers between these modes, i. Then all modes going from to in steps of i will be added to the set. i must be an integer such that is a whole number (not a fraction).

This parameter can be used only with DEFINITION=MODE NUMBERS.

Data lines if DEFINITION=MODE NUMBERS and the GENERATE parameter is omitted: 

First line:

  1. List of modes to be used.

Repeat this data line as often as necessary. Up to 16 entries are allowed per line.

Data lines if DEFINITION=MODE NUMBERS and the GENERATE parameter is included: 

First line:

  1. First mode number.

  2. Last mode number.

  3. Increment in mode numbers between modes. The default is 1.

Repeat this data line as often as necessary.

Data lines if DEFINITION=FREQUENCY RANGE: 

First line:

  1. Lower boundary of the frequency range (in cycles/time).

  2. Upper boundary of the frequency range (in cycles/time).

Repeat this data line as often as necessary.