Fig 1: Project Schematic
With the release of Mechanical 19.2, substructuring is now available for Modal & Rigid Dynamics without scripting. That just made my earlier post on CMS outdated! Note that there is still a key limitation where Generation and Expansion Pass must be performed on your local machine.
To get ahead of the game a bit, here is a way to do Harmonic Analysis extending on previous work. (Please go through that before this post). Some points of note:
- The method of merging the CMS and non-CMS models together into System C is the same.
- All files related to the superelement has to be copied over to the solver file directory as before.
- Modal analysis need not be performed first as the example here uses Full Method instead of Modal Superposition for simplicity.
- The script expands the responses the same way as Modal Analysis does so the script will look familiar.
Example: Harmonic Response to Unbalanced Force using CMS (Link)
Example: Modal and Harmonic Analyses of an Automotive Suspension Assembly Using CMS (Link)
Command Snippet for Combined Analysis D
!!!!! Save full model
!!!!! perform use pass solution
! Deletes body to be replaced by cms element
cmsel, s, BODY1_CMS_PART_ ! ** part named selection for deletion **
cmsel,u, interA_CMS_PART_ ! ** don't delete interface nodes **
*get, etmax, etyp, 0, num, max
et, etmax+1, 50 ! define substructure element type
se, myse ! define substructure element
/solu ! uses exisitng settings
!!!!! expand the solution for viewing purposes
seexp, myse, use ! substructure name and the use pass jobname
numexp, all,,, yes ! Expand all modes
!!!!! merge results file
nsubsteps = 3 ! **number of harmonic frequencies**
*do,ct, 1, nsubsteps
set, 1, ct
append, 1, ct
reswrite, file ! file name for results file
Model Comparison with verification model
Fig 2: CMS Model
Fig 3: Verification Model
Archived Model V19+
The archived file can be found here: Link
All posts on Superelement
CMS Superelement Harmonic Analysis Link
Reuse CMS Superelement in Ansys Workbench with Expansion Link
Component Mode Synthesis (CMS) with Results Expansion in Ansys Workbench Link
Craig Bampton Method Overview Link
Component Mode Synthesis(CMS) Substructure in ANSYS Workbench Link
In more recent version of Ansys Workbench, distributed file combinations defaults were changed to OFF. This needs to be corrected with appending the following commands to the Analysis A command snippet (Generation Pass).
dmpopt, esav, yes
dmpopt, emat, yes
dmpopt, full, yes
Update [Jan 18, 2020]
A new post shows the same procedure in Ansys 2019 r3.
Nice work, thanks!ReplyDelete
Can we use CMS for electric motor modal analysis, what I try to achieve is that stator, rotor, bearing, endplates, housing are independent components, and then use CMS to get the full motor assembly modes.ReplyDelete
Yes, you should be able to branch off multiple analysis for different components.Delete