Image of the settings in the "Eigenvalue Method" tab:
The settings in the "Eigenvalue Method" tab are organized into several sections:
Tab Section: Eigenvalue Method
| Lanczos
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- Default setting for direct determination of eigenvalues
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- The calculations converge quickly and provide very good results for low eigenvalues of small to medium-sized models with 10,000 to 100,000 degrees of freedom.
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| Roots of characteristic polynomial
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- Method with high accuracy for the calculation of higher eigenvalues
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- Suitable for small to medium-sized models (like Lanczos), but often with better performance
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| Subspace iteration method
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- Method with high stability/robustness for poorly conditioned (numerically unstable) matrices
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- Not suitable for complex systems; negative load factors may occur.
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| Shifted inverse iteration
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- Method with short calculation time due to fast convergence
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- Results between the largest and smallest eigenvalue of the given matrix can also be determined.
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Tab Section: Matrix Type
| Standard
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- Calculation using the geometric stiffness matrix of the linear equation system
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| Unit (for checking and determination of precision)
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- Calculation without consideration of the physical properties of the model by using the unit matrix
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- Use as a reference for numerical and kinematic analyses
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