Products: Abaqus/Standard Abaqus/AMS
Benefits: Enhancements to the AMS eigensolver improve the performance of frequency extraction analyses.
Description: Several enhancements to the AMS eigensolver have been made in Abaqus 6.9-EF and Abaqus 6.10.
A new procedure for handling a large number of constraints in the AMS eigensolver delivers improved performance for large models with many distributing coupling constraints or other Lagrange multiplier-based features (i.e., contact, connector elements, hyperelastic materials). Table 6–2 demonstrates improved AMS performance in Abaqus 6.9-EF for two industrial vehicle models.
Table 6–2 AMS performance improvements due to enhancement of handling a large number of constraints in Abaqus 6.9-EF.
| Model | Degrees of Freedom (Millions) | Number of Constraint Equations | Abaqus 6.9 Wall Clock Time (h:mm) | Abaqus 6.9-EF Wall Clock Time (h:mm) |
|---|---|---|---|---|
| Model 1 | 3.0 | 169,464 | 3:01 | 1:58 |
| Model 2 | 4.3 | 285,816 | 0:49 | 0:34 |
Enhancements in the reduction phase and the recovery phase of the Abaqus 6.10 AMS eigensolver deliver noticeably improved performance for large-scale models with any of the following features:
Selective recovery with a large number of selected degrees of freedom
Structural or viscous damping
Acoustic-structural coupling
Table 6–3 AMS performance improvements due to enhancement of the reduction phase and the recovery phase in Abaqus 6.10.
| Model | Degrees of Freedom (Millions) | Abaqus 6.9-EF | Abaqus 6.10 | ||
|---|---|---|---|---|---|
| Number of Modes Extracted | Wall Clock Time (h:mm) | Number of Modes Extracted | Wall Clock Time (h:mm) | ||
| Model 3 | 2.8 | 4434 | 0:46 | 4413 | 0:30 |
| Model 4 | 4.3 | 1715 | 3:07 | 1709 | 0:55 |
| Model 5 | 9.2 | 4221 | 5:45 | 4206 | 1:25 |
Due to these enhancements and the approximate nature of the AMS technology, it is possible to observe slight differences in the number of eigenmodes extracted by AMS in Abaqus 6.10 versus Abaqus 6.9-EF and compared to previous releases. These differences are expected since AMS eigenmodes close to the user-specified maximum frequency are generally less accurate and more sensitive to some perturbations (e.g., changes in the order of the system of equations). However, the results of subsequent modal dynamic procedures are very close to the results in Abaqus 6.9-EF and previous releases if an appropriate number of modes is used to construct the projection basis.
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