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Non Linear Optimization with Pretension

Altair Forum User

Hello All,

I am running a Non Linear Optimization with the following load conditions:

STEP-1

Assembly fit using PCONT clearance

Pretension

STEP-2

Temperature change from 23 degres to -40 degrees

Non linear optistruct run was clear but when I run the model for optimization I get the following error:

*** ERROR # 415 ***
Static Subcase 2 has 'STATSUB(PRETENS)' defined.
Optimization with compliance cannot be performed.

Any suggestions will be highly appreciated.

Thanks

Praveen

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All comments

Rahul Rajan_21763

What type of optimization you are running , Responses & Version of Hyperworks?

Attached screenshot for Thermal compliance(Version 14.0)

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

Hi Rahul,

My Hyperworks version is V14.0 student edition, but I can not find the 'thermal compliance' in the 'response' panel, I can only find 'temperature' response.

Could you advise? thanks.

Neo

Altair Forum User

Hi @wumindao

Thermal Compliance is currently not available through Student Edition. It was added in of the 14.0 updates which is not a part of Student Edition.

as a workaround, you can add thermal compliance as shown in image below by editing the deck in any text pad.

Thermal compliance will be a part of responses in Student Edition in coming release.

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

Hi @wumindao

Thermal Compliance is currently not available through Student Edition. It was added in of the 14.0 updates which is not a part of Student Edition.

as a workaround, you can add thermal compliance as shown in image below by editing the deck in any text pad.

Thermal compliance will be a part of responses in Student Edition in coming release.

<?xml version="1.0" encoding="UTF-8"?>

Hi Prakash Pagadala,

Thanks for your reply!

I have done so, but there was an error after the run.

The error message is ' DRESP1 1 is not referenced from within a linear heat transfer SUBCASE.
This type of response must be specified from within a linear heat transfer SUBCASE.'

(Note: DRESP1 is Thermal Compliance, I set VolumeFrac<=0.3 as a constraint, and set TCOMP be min. as objective. )

Could you please advise that how to make the response 'Thermal compliance' be specified from a Subcase?

Altair Forum User

Hi,

Is it possible to share the model file?

If yes, please use the file transfer link in my signature below to share files.

Altair Forum User

Hi,

Is it possible to share the model file?

If yes, please use the file transfer link in my signature below to share files.

Hi Prakash,

I am sorry but I can't find your signature as well as the 'transfer link', the signature not displayed.

Please find the file as attached.

Actually, I want to do a thermal topology optimization , same as the one in this paper:

https://www.researchgate.net/publication/304703093_Thermal_Topology_Optimization_in_OptiStruct_Software

Could you suggest some examples for me to do the thermal topology optimization? Thanks very much!

Unable to find an attachment - read this blog

Altair Forum User

@wumindao

I will share another modified file with you soon by mail.

But Currently QBDY1 is not allowed in design domain. You will end-up with new error message. Make neccesary modifications and run the model.

Altair Forum User

@wumindao

I will share another modified file with you soon by mail.

But Currently QBDY1 is not allowed in design domain. You will end-up with new error message. Make neccesary modifications and run the model.

Hi Prakash,

Thanks for your help!

Appreciate that if you could just make a simple file and shared with me.

As refer to attached files, could you just make a file that same as chapter 6.1 in the attached paper? I have made one but the error still come out which is ' DRESP1 1 is not referenced from within a linear heat transfer SUBCASE. This type of response must be specified from within a linear heat transfer SUBCASE.'

<?xml version="1.0" encoding="UTF-8"?>

Unable to find an attachment - read this blog

Altair Forum User

Hi,

Try this atatched file

<?xml version="1.0" encoding="UTF-8"?>

Unable to find an attachment - read this blog

Altair Forum User

Hi Prakash,

Your file works very well ! Thanks.

But I modified my file (e.g., make a new component which is non-design space, added VolumeFrac) and make it looks same as your one, but the error message still come out which is ' DRESP1 1 is not referenced from within a linear heat transfer SUBCASE. This type of response must be specified from within a linear heat transfer SUBCASE.' .

May I know where you have modified ?

Altair Forum User

@wumindao

The reason is that TCOMP response should be within subcase. I moved the response within subcase (you can edit the file and see the changes)

Altair Forum User

Hi Prakash,

I got it, thanks!

Altair Forum User

hello prakash,

I am facing the same problem,

DRESP1 1 is not referenced from within a statis subcase.

This type of response must be specified from within a static subcase.

This error occurs in MINMAX 2.

I dont know what the issue is, below is the .fem file

$$ optistruct
$
DISPLACEMENT(H3D) = ALL
ENERGY(H3D) = YES
MINMAX = 1
$$------------------------------------------------------------------------------$
$$ Case Control Cards $
$$------------------------------------------------------------------------------$
$$
$$ OBJECTIVES Data
$$
$
DESGLB 2
$
$
$HMNAME LOADSTEP 1'normal_modes' 3
$
SUBCASE 1
LABEL normal_modes
ANALYSIS MODES
SPC = 3
METHOD(STRUCTURE) = 2
$$--------------------------------------------------------------
$$ HYPERMESH TAGS
$$--------------------------------------------------------------
$$BEGIN TAGS
$$END TAGS
$
BEGIN BULK
$$
$$ Stacking Information for Ply-Based Composite Definition
$$
$
$HMSET 2 1 'cons'
SET 2 GRID LIST
+ 1909658 THRU 1909663
+ 1909999 THRU 1910006
+ 1909665 1909666

$HMNAME DESVARS 1topo
DTPL 1 PSOLID 73
+ MEMBSIZ 15.0
+ DRAW SINGLE 7036745 7036750
+ OBST 72
$$
$$ OPTIRESPONSES Data
$$
DRESP1 2 volfrac VOLFRAC
DRESP1 1 com COMP
$$
$$ OPTICONSTRAINTS Data
$$
$
$HMNAME OPTICONSTRAINTS 1cons
$
DCONSTR 1 2 0.3

DCONADD 2 1

$$
$$ OBJECTIVE REFERENCE Data
$$
$
$HMNAME DOBJREF 1'MAX_Comp'
$
DOBJREF 1 1 1 -1.0 1.0
$
PARAM,CHECKEL,NO
$$
$$ GRID Data
$$
GRID 501 -369.646-44.6784304.9563
GRID 3709 -210.0 -119.061-19.825

Altair Forum User

Hi @iamyasir

Can you edit the file and move the MINMAX below the casecontrol cards section or just above the HyperMesh Tags section?

If this did not work, Is it possible to share the model file?

Please share using the file transfer link in my signature below.

Altair Forum User

Hey Prakash,

Thanks a lot for your resposne.

I will try moving the MINMAX below the case control section as you suggested.

Other question that i had is, if i can create constraints for stifness in X,Y and Z direction

Below is the optimization setup that i want to run:-

Objective: Min (Weighted compliance)
Constraint 1: Volume fraction < Target Percentage
Constraint 2: Frequency > Targeted Frequency
Constraint 4: Stiffness in X-direction > Target X
Constraint 5: Stiffness in Y-direction > Target Y
Constraint 6: Stiffness in Z-direction > Target Z

Can you please help me in setting up the model.

Thank you

Regards

Yasir

Altair Forum User

Hi,

You can constrain the displacement in directions. But I see a conflict with objective and constrains as minimizing compliance is same as increasing stiffness...