*BUCKLE

Obtain eigenvalue buckling estimates.

This option is used to control eigenvalue buckling estimation.

This page discusses:

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Eigenvalue Buckling Prediction

ProductsAbaqus/StandardAbaqus/CAE

TypeHistory data

LevelStep

Abaqus/CAEStep module

Optional parameters

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. Abaqus/Standard usually determines this number, but you can change the number 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. Providing this value directs the Lanczos solution procedure to find eigenvalues near this value with minimal computational effort. Lower eigenvalues might also be found with no additional computational cost. If this field is left blank, no minimum is set.

  3. Maximum eigenvalue of interest. Providing this value directs the Lanczos solution procedure to find eigenvalues near this value with minimal computational effort. Higher eigenvalues might also be found with no additional computational cost. 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.