FW: Crowd sourcing : turning off spin softening for a modal analysis
Hi All,
I have rotating part that I'm doing a cyclic symmetry (1/8 sector) prestressed modal analysis on. One of the requirements I was given was for spin softening to be turned OFF for the modal analysis.
Seems to be on by default....options for modal analysis
L O A D S T E P O P T I O N S
LOAD STEP NUMBER. . . . . . . . . . . . . . . . 1
CYCLIC SYMMETRY HARMONIC INDEX. . . . . . . . . 4
SPIN SOFTENING EFFECTS. . . . . . . . . . . . . ON
INERTIA LOADS X Y Z
OMEGA. . . . . . . . . . . . 0.0000 0.0000 1561.8
PRINT OUTPUT CONTROLS . . . . . . . . . . . . .NO PRINTOUT
DATABASE OUTPUT CONTROLS. . . . . . . . . . . .ALL DATA WRITTEN
For some reason I thought turning it off was part of the omega command, but I seem be wrong.
The CORIOLIS command looks like it might be the ticket, but not sure. Also not sure that command works on my element type (SOLID45).
Is it as simple as setting the speed to zero for the modal solution? I am not even sure what Ansys does with speed in a modal solution.
Hope someone out there has dealt with this.
Thanks,
Dan Bohlen
Senior Engineer, Stress Analysis
STAR review chairman, military structures
NGP engine focal
GE Aerospace
1 Neumann Way
Evendale, OH 45215 USA
Build B90 Col. H5 cube BK35-251
M/D H358 Cell 513-917-3402
Building 200 Col. G3 cube BC088 Desk Phone 3-8816
GE FOCUS: Safety, Quality, Delivery, Cost
"In God we trust, all others bring data." W Edwards Deming
Dan,
I fought long and hard to get them to add Spin Softening. But I also seem to remember a way to turn it on and off. But can't remember what.
I assume you want stress stiffening, but not spin softening? If not, then just setting omega to 0 will work.
The program calculates the adjustment to the stiffness matrix if any of the following are turned on: NLGEOM, On, PSTRES, On, or CORIOLIS, ON
You probably want keep the PSTRES, ON. So I'm not sure how to do stress stiffening and not spin softening.
3.5 in the Theory manual goes over all the minutia.
So I'm stumped as well.
Eric
-----------------------------
Eric Miller
Co-Owner & Principal
PADT, Inc.
www.padtinc.com
480.813.4884
eric.miller@padtinc.com
-----------------------------
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-----Original Message-----
From: Bohlen, Dan (GE Aerospace, US) dan.bohlen@ge.com
Sent: Wednesday, March 22, 2023 5:24 AM
To: XANSYS Mailing List Home xansys-temp@list.xansys.org
Subject: [Xansys] FW: Crowd sourcing : turning off spin softening for a modal analysis
Hi All,
I have rotating part that I'm doing a cyclic symmetry (1/8 sector) prestressed modal analysis on. One of the requirements I was given was for spin softening to be turned OFF for the modal analysis.
Seems to be on by default....options for modal analysis
L O A D S T E P O P T I O N S
LOAD STEP NUMBER. . . . . . . . . . . . . . . . 1
CYCLIC SYMMETRY HARMONIC INDEX. . . . . . . . . 4
SPIN SOFTENING EFFECTS. . . . . . . . . . . . . ON
INERTIA LOADS X Y Z
OMEGA. . . . . . . . . . . . 0.0000 0.0000 1561.8
PRINT OUTPUT CONTROLS . . . . . . . . . . . . .NO PRINTOUT
DATABASE OUTPUT CONTROLS. . . . . . . . . . . .ALL DATA WRITTEN
For some reason I thought turning it off was part of the omega command, but I seem be wrong.
The CORIOLIS command looks like it might be the ticket, but not sure. Also not sure that command works on my element type (SOLID45).
Is it as simple as setting the speed to zero for the modal solution? I am not even sure what Ansys does with speed in a modal solution.
Hope someone out there has dealt with this.
Thanks,
Dan Bohlen
Senior Engineer, Stress Analysis
STAR review chairman, military structures NGP engine focal GE Aerospace
1 Neumann Way
Evendale, OH 45215 USA
Build B90 Col. H5 cube BK35-251
M/D H358 Cell 513-917-3402
Building 200 Col. G3 cube BC088 Desk Phone 3-8816
GE FOCUS: Safety, Quality, Delivery, Cost
"In God we trust, all others bring data." W Edwards Deming
Xansys mailing list -- xansys-temp@list.xansys.org To unsubscribe send an email to xansys-temp-leave@list.xansys.org If you are receiving too many emails from XANSYS please consider changing account settings to Digest mode which will send a single email per day.
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Below link may provide some thought
https://imechanica.org/node/3792
Please copy and paste above path
On Wed, 22 Mar, 2023, 5:54 pm Bohlen, Dan (GE Aerospace, US), <
dan.bohlen@ge.com> wrote:
Hi All,
I have rotating part that I'm doing a cyclic symmetry (1/8 sector)
prestressed modal analysis on. One of the requirements I was given was
for spin softening to be turned OFF for the modal analysis.
Seems to be on by default....options for modal analysis
L O A D S T E P O P T I O N S
LOAD STEP NUMBER. . . . . . . . . . . . . . . . 1
CYCLIC SYMMETRY HARMONIC INDEX. . . . . . . . . 4
SPIN SOFTENING EFFECTS. . . . . . . . . . . . . ON
INERTIA LOADS X Y Z
OMEGA. . . . . . . . . . . . 0.0000 0.0000 1561.8
PRINT OUTPUT CONTROLS . . . . . . . . . . . . .NO PRINTOUT
DATABASE OUTPUT CONTROLS. . . . . . . . . . . .ALL DATA WRITTEN
For some reason I thought turning it off was part of the omega command,
but I seem be wrong.
The CORIOLIS command looks like it might be the ticket, but not sure.
Also not sure that command works on my element type (SOLID45).
Is it as simple as setting the speed to zero for the modal solution? I am
not even sure what Ansys does with speed in a modal solution.
Hope someone out there has dealt with this.
Thanks,
Dan Bohlen
Senior Engineer, Stress Analysis
STAR review chairman, military structures
NGP engine focal
GE Aerospace
1 Neumann Way
Evendale, OH 45215 USA
Build B90 Col. H5 cube BK35-251
M/D H358 Cell 513-917-3402
Building 200 Col. G3 cube BC088 Desk Phone 3-8816
GE FOCUS: Safety, Quality, Delivery, Cost
"In God we trust, all others bring data." W Edwards Deming
Xansys mailing list -- xansys-temp@list.xansys.org
To unsubscribe send an email to xansys-temp-leave@list.xansys.org
If you are receiving too many emails from XANSYS please consider changing
account settings to Digest mode which will send a single email per day.
Please send administrative requests such as deletion from XANSYS to
xansys-mod@tynecomp.co.uk and not to the list
Is this what you're looking for ?
Keith DiRienz, P.E.
FEA Technologies
Dana Point, CA
Modal Analysis Options Category
For Modal analyses, the Options group includes the following
controls:Max Modes to Find
Specifies the number of natural frequencies to solve for in a modal analysis.
Limit Search Range
Allows you to specify a frequency range within which to find the
natural frequencies. The default is set to No. If you set this to
Yes, you can enter a minimum and maximum frequency value. If you
specify a range the solver will strive to extract as many frequencies
as possible within the specified range subject to a maximum specified
in the Max Modes to Find field.
Spin Softening
Enables you to specify whether to include or exclude Spin Softening
effect in the linear perturbation analyses. This field is available
when performing a Pre-Stressed Modal analysis. The options include
Program Controlled (default), Yes, and No. The Program Controlled
setting selects either to include or exclude Spin Softening in the
solution based on whether the rotating reference frame attached to
the body is fixed (Yes) or in motion (No). The Yes option is invalid
if the Coriolis Effect property
(file:///C:/Program%20Files/ANSYS%20Inc/v182/commonfiles/help/en-us/help/wb_sim/ds_rotordyn_controls.htmlRotordynamics
Controls) is set to On.
For more information, refer to the
file:///C:/Program%20Files/ANSYS%20Inc/v182/commonfiles/help/en-us/help/ans_cmd/Hlp_C_PERTURB.htmlPERTURB
command from MAPDL Command Reference Guide.
At 05:24 AM 3/22/2023, you wrote:
Hi All,
I have rotating part that I'm doing a cyclic symmetry (1/8 sector)
prestressed modal analysis on. One of the requirements I was given
was for spin softening to be turned OFF for the modal analysis.
Seems to be on by default....options for modal analysis
L O A D S T E P O P T I O N S
LOAD STEP NUMBER. . . . . . . . . . . . . . . . 1
CYCLIC SYMMETRY HARMONIC INDEX. . . . . . . . . 4
SPIN SOFTENING EFFECTS. . . . . . . . . . . . . ON
INERTIA LOADS X Y Z
OMEGA. . . . . . . . . . . . 0.0000 0.0000 1561.8
PRINT OUTPUT CONTROLS . . . . . . . . . . . . .NO PRINTOUT
DATABASE OUTPUT CONTROLS. . . . . . . . . . . .ALL DATA WRITTEN
For some reason I thought turning it off was part of the omega
command, but I seem be wrong.
The CORIOLIS command looks like it might be the ticket, but not
sure. Also not sure that command works on my element type (SOLID45).
Is it as simple as setting the speed to zero for the modal
solution? I am not even sure what Ansys does with speed in a modal solution.
Hope someone out there has dealt with this.
Thanks,
Dan Bohlen
Senior Engineer, Stress Analysis
The perturb,,spoff command that Keith mentioned seems to be the way to go.
You can probably blame me for the spin softening setting not on the omega
command anymore. I lobbied ANSYS years ago to make it a default because I
couldn't see a case where it wasn't valid to include it.
BTW.... stress stiffening, spin softening, and Coriolis are all different
effects.
Joseph T Metrisin
Structures Lead
Florida Turbine Technologies, Inc a KRATOS Company
1701 Military Tr. Suite 110 | Jupiter, FL 33458 USA
+1 (561) 427-6346 Office | +1 (772) 834-4156 Mobile
Joe.Metrisin@kratosdefense.com
We are hiring; Join the FTT Team in Jupiter, Florida
Visit our website: https://kratosdefense.com
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-----Original Message-----
From: Bohlen, Dan (GE Aerospace, US) dan.bohlen@ge.com
Sent: Wednesday, March 22, 2023 8:24 AM
To: XANSYS Mailing List Home xansys-temp@list.xansys.org
Subject: [External] - [Xansys] FW: Crowd sourcing : turning off spin
softening for a modal analysis
CAUTION: This email originated from outside of the organization. Do not
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Hi All,
I have rotating part that I'm doing a cyclic symmetry (1/8 sector)
prestressed modal analysis on. One of the requirements I was given was for
spin softening to be turned OFF for the modal analysis.
Seems to be on by default....options for modal analysis
L O A D S T E P O P T I O N S
LOAD STEP NUMBER. . . . . . . . . . . . . . . . 1
CYCLIC SYMMETRY HARMONIC INDEX. . . . . . . . . 4
SPIN SOFTENING EFFECTS. . . . . . . . . . . . . ON
INERTIA LOADS X Y Z
OMEGA. . . . . . . . . . . . 0.0000 0.0000 1561.8
PRINT OUTPUT CONTROLS . . . . . . . . . . . . .NO PRINTOUT
DATABASE OUTPUT CONTROLS. . . . . . . . . . . .ALL DATA WRITTEN
For some reason I thought turning it off was part of the omega command, but
I seem be wrong.
The CORIOLIS command looks like it might be the ticket, but not sure. Also
not sure that command works on my element type (SOLID45).
Is it as simple as setting the speed to zero for the modal solution? I am
not even sure what Ansys does with speed in a modal solution.
Hope someone out there has dealt with this.
Thanks,
Dan Bohlen
Senior Engineer, Stress Analysis
STAR review chairman, military structures NGP engine focal GE Aerospace
1 Neumann Way
Evendale, OH 45215 USA
Build B90 Col. H5 cube BK35-251
M/D H358 Cell 513-917-3402
Building 200 Col. G3 cube BC088 Desk Phone 3-8816
GE FOCUS: Safety, Quality, Delivery, Cost
"In God we trust, all others bring data." W Edwards Deming
Xansys mailing list -- xansys-temp@list.xansys.org To unsubscribe send an
email to xansys-temp-leave@list.xansys.org If you are receiving too many
emails from XANSYS please consider changing account settings to Digest mode
which will send a single email per day.
Please send administrative requests such as deletion from XANSYS to
xansys-mod@tynecomp.co.uk and not to the list