part modify flexible_body auto_disable_modes
After performing a pilot simulation, you can disable those modes that do not significantly contribute to the total strain energy of a flexible body. You can set Adams View to automatically disable any modes that contributed less than a specified fraction of the total strain energy during the test simulation. After disabling the modes that do not significantly contribute to strain energy, simulation times should be reduced.
The pilot simulation that you run should be typical of the simulations that you are going to run on the flexible body. Disabling a particular set of modes based on the simulation of one event might be totally inappropriate when simulating another unrelated event.
An important energy contribution from a model might be of a short duration that its total energy can seem insignificant but yet the mode is important to the simulation. For example, although the strain energy that a mode contributes may be quite low compared to the total strain energy for the entire simulation, Adams Solver may be unable to complete the simulation without the mode. Therefore, you should choose a very conservative strain energy fraction (for example, 0.001 or smaller). If a mode is truly inactive, it will be disabled in spite of a low setting.
Format:
part modify flexible_body auto_disable_modes |
|---|
flexible_body_name= | existing flex body |
energy_tolerance= | real |
analysis_name= | existing analysis |
Example:
part modify flexible_body auto_disable_modes & |
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flexible_body_name = | flex_body_1 & |
energy_tolerance = | 0.001 & |
analysis_name = | last_run |
Adams Flex will disable all modes that contributed less than the 0.1% to the total strain energy during the test simulation.
Description:
Parameter | Value Type | Description |
|---|
flexible_body_name | Existing flex body | Specifies the name of an existing flexible body to be modified |
energy_tolerance | Real | Specifies a real number greater than 0 and less than 1. |
analysis_name | Existing analysis | Specifies an existing analysis |
Extended Definition:
1. You may identify a flexible body by typing its name, by selecting it from the database navigator's select list or by picking its graphical representation from the screen, whichever is most convenient.
If Adams View created the flexible body by reading an Adams data set, the name may either come from the "adams_view_name" field of the preceding comment, or be synthesized from the Adams ID number. In the case that the flexible body is created as a result of reading a results or graphics file, the flexible body name will be synthesized from the Adams ID number. When the name is created by Adams View it will be composed of "FLX" concatenated with the Adams data set flexible body ID number. For example, the Adams View name of FLEX_BODY/42 would be FLX42. Flexible bodies you create during preprocessing have user-specified names.
You may identify a flexible body belonging to the current default model by entering just its name. For others, you must enter the full name. To identify a flexible body under another model, for instance, you need to enter the model name as well. For example, you may specify flexible body 'snake' from model 'reptiles' by entering ".reptiles.snake". You can invoke the database navigator by typing "?", which will bring up the select list from which you can pick a flexible body.
For commands which accept multiple flexible body names, you must separate the names by commas.
If the flexible body is visible in one of your views, you may identify it by picking on any of the graphics associated with it. When you do this, Adams View will automatically separate multiple flexible body picks by commas.
2. Adams Flex will disable those modes that contributed less than the fraction specified in the energy_tolerance parameter of the total strain energy during the test simulation.
Cautions:
1. Disabling an important mode can, however, adversely affect the numerical conditioning of a flexible body model. The computational savings that you gain by disabling a mode can be quickly lost by the computational cost of a difficult simulation.