Analysis Control - Time History
<Time History Analysis Control> Eigen Vector Type Subspace Iteration Subspace Iteration matrix calculation is used to perform Eigenvalue analysis. Lanczos Tridiagonal Matrix is used to perform Eigenvalue analysis. Eigen Vectors Number of Frequencies Enter the number natural frequencies to be computed for the structure . Cut Off Frequencies Set the range of the frequencies of the structure to be computed from a minimum to a maximum. Lower Limit Minimum frequency in the range Upper Limit Maximum frequency in the range The computation starts from the set Lower Frequency, and the Frequencies are computed within the set range. If the computed natural frequency turns out to be larger than the set Upper Frequency, no additional frequencies are calculated. Only the values smaller than the Upper Frequency are used in the ensuing analysis. Eigenvalue Control Parameters Enter the Frequency Shift to obtain the maximum number of iterations, the subspace size, the convergence tolerance and the rigid body behavior. These parameters are necessary when the Subspace Iteration method is used for Eigenvalue analysis. The Subspace Iteration Method is used for Eigenvalue analysis in MIDAS/GTS. The iteration continues until the relative frequency calculated does not exceed the convergence tolerance. If the relative natural frequencies are not within the convergence tolerance after the maximum number of iterations is exhausted, no additional calculation is performed and the previously calculated natural frequencies are used for the subsequent tasks. Eigenvalue analysis and Buckling Analysis cannot be performed simultaneously. Eigenvalue analyses must precede dynamic analyses such as Time History analysis or Response Spectrum analysis. The Response Spectrum analysis uses the natural periods from the Eigenvalue analysis. Thus, the entered spectral data must include the expected range of natural periods. Number of Iteration Enter the maximum number of iterations. Subspace Dimension Enter the subspace size. Convergence Tolerance Enter the convergence tolerance. Frequency Shift Enter the frequency shift to compute rigid body motion. Skip Eigenvalue Analysis (Not Applicable if Eigenvalue Analysis is Compulsory)

Analysis Control - Time History

Eigen Vector Type

Subspace Iteration

Subspace Iteration matrix calculation is used to perform Eigenvalue analysis.
Lanczos

Tridiagonal Matrix is used to perform Eigenvalue analysis.

Eigen Vectors

Number of Frequencies

Enter the number natural frequencies to be computed for the structure .
Cut Off Frequencies

Set the range of the frequencies of the structure to be computed from a minimum to a maximum.

Lower Limit

Minimum frequency in the range

Upper Limit

Maximum frequency in the range

The computation starts from the set Lower Frequency, and the Frequencies are computed within the set range. If the computed natural frequency turns out to be larger than the set Upper Frequency, no additional frequencies are calculated. Only the values smaller than the Upper Frequency are used in the ensuing analysis.

Eigenvalue Control Parameters

Enter the Frequency Shift to obtain the maximum number of iterations, the subspace size, the convergence tolerance and the rigid body behavior. These parameters are necessary when the Subspace Iteration method is used for Eigenvalue analysis.

The Subspace Iteration Method is used for Eigenvalue analysis in MIDAS/GTS. The iteration continues until the relative frequency calculated does not exceed the convergence tolerance.

If the relative natural frequencies are not within the convergence tolerance after the maximum number of iterations is exhausted, no additional calculation is performed and the previously calculated natural frequencies are used for the subsequent tasks.

Eigenvalue analysis and Buckling Analysis cannot be performed simultaneously. Eigenvalue analyses must precede dynamic analyses such as Time History analysis or Response Spectrum analysis.

The Response Spectrum analysis uses the natural periods from the Eigenvalue analysis. Thus, the entered spectral data must include the expected range of natural periods.

Number of Iteration

Enter the maximum number of iterations.

Subspace Dimension

Enter the subspace size.

Convergence Tolerance

Enter the convergence tolerance.

Frequency Shift

Enter the frequency shift to compute rigid body motion.

Skip Eigenvalue Analysis (Not Applicable if Eigenvalue Analysis is Compulsory)