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thermal analysis

Altair Forum User

hello

I want to do simple problem in hypermesh

a circular rod with both ends fixed

initial temp is 20 dec

and heated to 300dec

what wwill be stresses due to thermal expansion????????????

how to do this problem in radioss

and i want to use output of this analysis and continue the analysis to frf so can we do that?

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Altair Forum User

Hi Sagar,

Refer to the OptiStruct tutorial: OS-1010: Thermal Stress Analysis of a Coffee Pot Lid

Altair Forum User

thank you

so now i have thermal analysis results

now i want to continue my analysis and conduct frf analysis after thermal analysis

i think it can be done by cntnlsub r8?

even i can do it for large problem only doing frf will consuming lot of scratch space and ram

then simultaneously running the both loadcase thermal and frf need even more sources

so is there any way in which i can carry out thermal separatly and frf separatly with giving thermal output as input to frf?

Altair Forum User

HI Sagar,

CNTNLSUB is valid only for Non-linear subcases.

Can you explain your objective exactly so that I can suggest the best way to work.

Altair Forum User

i am having a pipe connected with metal bellows

in contact with hot air (inducing thermal stresses)

and i want to perform frf on this?

Rahul Rajan_21763

Yes, you can use OptiStruct. There is no temperature load referencing in FRF analysis. It needs to run thermal-structural analysis and preloading for FRF in the following way,

1. Create heat transfer subcase (100) to obtain temperature distribution

2. Create static subcase (200) to run thermal-structural analysis using TEMP(LOAD, or BOTH) = 100

3. Create eigenvalue subcase (300) with same b.c. as modal FRF subcase and use preloading from Subcase 200.

4. Create modal FRF subcase for vibration load (preloading only works for modal FRF, not direct FRF). It will use modal space from subcase 300 which is preloaded.

Please let me know if you have any question.

Altair Forum User

Hi,

I want to do a thermal analysis using RADIOSS, as it involves impact as well. In optistruct, I have done the thermal analysis using MAT1 wherein I specified the thermal expansion coefficient (A). What material should I use in RADIOSS and how can I specify the thermal expansion coefficient.

Thanks and Regards,

Sai Phanindra

Altair Forum User

Hi Sai,

Check LAW 18. Purely thermal material

Altair Forum User

You can also give conductivity, temperture exponent in LAW2 isotropic non linear.

Altair Forum User

Hi Prakash,

I know the value of thermal expansion coefficient (alpha). Can you guide me how it converts to the temperature exponent in LAW2?

Thanks,

Sai

Altair Forum User

Sai,

these are the available entries to consider thermal role in LAW2.

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

RAMGANESH

Yes, you can use OptiStruct. There is no temperature load referencing in FRF analysis. It needs to run thermal-structural analysis and preloading for FRF in the following way,

1.       Create heat transfer subcase (100) to obtain temperature distribution

2.       Create static subcase (200) to run thermal-structural analysis using TEMP(LOAD, or BOTH) = 100

3.       Create eigenvalue subcase (300) with same b.c. as modal FRF subcase and use preloading from Subcase 200.

4.       Create modal FRF subcase for vibration load (preloading only works for modal FRF, not direct FRF). It will use modal space from subcase 300 which is preloaded.

Please let me know if you have any question.

Dear Rahul,

Similar kind of problem i want to solve in optistruct.

i want to check the structural integrity of my model under the loading conditions of inertial force in all direction, pressure loading,Temperature loading and under certain frequency range.

Kindly provide your valuable guidelines

Thanks

RAM

Rahul Rajan_21763

We will continue this discussion in seperate post you created.