Combine a sol106 static solution with a static thermal subcase.

I have flexure that I am using a solution 106 to deflect part of the flexure with an SPCD in steps up to full pre-load. From this pre-loaded state, I would like to add a thermal soak on the pre-loaded flexure from this last load step. There are four thermal cases I wanted to consider to combine with the last static load step, if that is possible.

0 Sanjay Patel over 4 years ago

Hi Derek,

Solution setup would be as follows. SUBCASE 2 starts from where SUBCASE 1 ended. And only additional loading that is in subcase 2 is applied. In the case below LOAD=1 was fully applied in subcase 1 and needs to be carried thru in subcase 2 so total mechanical loading in subcase 2 will be the same as subcase 1. It does not apply additional loading in subcase 2. If you remove the load entry in second subcase it has effect of unloading the mechanical loading in the structure.

SOL 106

CEND

TEMP(INIT)=100

SUBCASE 1

LOAD=1

SUBCASE 2

LOAD=1

TEMP(LOAD)=10

SUBCASE 3

LOAD=1

TEMP(LOAD)=20

SUBCASE 4

LOAD=1

TEMP(LOAD)=40
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0 Don.Graff over 4 years ago

As long as the type of temperature loading is just a standard delta-t type load, not radiation, conduction, etc, then this should be possible with SOL106. I found a sample workshop with a preload subcase followed by a temp loading subcase. It uses temperature dependent material properties, but that is not necessary. I'll attach the pdf first and then the Nastran input file.

Attached Files (1)

Chap5-WS5-temp-dep-mat.pdf
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0 Don.Graff over 4 years ago

here is the input file...

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chap55s1-150.dat
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0 derek.lewis over 4 years ago

Could I use the final pre-load subcase as the start point for several thermal load cases? Starting from the nominal pre-load, I might consider a cold, hot and a survival case for different delta-T from room temperature.
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0 Sanjay Patel over 4 years ago

Yes, what ever the the final pre-load is, you will have to carry it thru the subsequent subcases.
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0 Don.Graff over 4 years ago

But if you want to only start from the end of the preload, and pick up with a new temp loading condition, you would have to do a RESTART. You run the first SOL106 up to the end of the preload, and keep the resulting Master/DBALL/IFPDAT files, and then you can restart of that solution into a new loading condition... you would run as many separate restart runs as there are separate thermal load cases. Of course, if you want to go from the end condition of one thermal loading into the next thermal loading, RESTART is not needed... just stack the subcases in the order you want the loading to progress.

I'll attach a simple read-only restart example.

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plate-run1.dat
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0 Don.Graff over 4 years ago

then the restart file...

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plate-run2.dat
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0 derek.lewis over 4 years ago

There isnt an option using subcase selection for the thermal cases?
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0 Don.Graff over 4 years ago

I don't think so- if anyone else knows otherwise, please add a comment! That is possible in a SOL400 run, where you can point to the desired previous STEP for a new STEP/Subcase.
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0 derek.lewis over 4 years ago

I have RBE2s with CTE values on them. Would I add a TEMP(INIT) case command above the subcases?
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