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*BUCKLE
Obtain eigenvalue buckling estimates.

This option is used to control eigenvalue buckling estimation.

Products: Abaqus/Standard  Abaqus/CAE  

Type: History data

Level: Step

Abaqus/CAE: Step module

Reference:

Optional parameter:

EIGENSOLVER

Use this parameter to choose the eigensolver.

Set EIGENSOLVER=SUBSPACE (default) to invoke the subspace iteration eigensolver.

Set EIGENSOLVER=LANCZOS to invoke the Lanczos eigensolver.

Data line for an eigenvalue buckling analysis when EIGENSOLVER=SUBSPACE: 

First (and only) line:

  1. Number of eigenvalues to be estimated.

  2. Maximum eigenvalue of interest.

  3. Number of vectors used in the iteration. This number is usually determined by Abaqus/Standard but can be changed using this entry. In general, the convergence in solving the eigenproblem is more rapid if more vectors are carried in the iteration; therefore, use this data field if past experience suggests that the convergence is slow for a particular type of buckling problem. If the number of eigenvalues requested is n, the default number of vectors used is the minimum of (2n, n+8).

  4. Maximum number of iterations. The default is 30.

Data line for an eigenvalue buckling analysis when EIGENSOLVER=LANCZOS: 

First (and only) line:

  1. Number of eigenvalues to be estimated. If the evaluation of all the eigenvalues in the given range is desired, enter the maximum number of expected eigenmodes.

  2. Minimum eigenvalue of interest. If this field is left blank, no minimum is set.

  3. Maximum eigenvalue of interest. If this field is left blank, no maximum is set.

  4. Block size. If this entry is omitted, a default value, which is usually appropriate, is created.

  5. Maximum number of block Lanczos steps within each Lanczos run. If this entry is omitted, a default value, which is usually appropriate, is created.