Using New configuration to set up Multistep Analysis

disla

Hi,

I have used the “New configuration” sheets in Mecway to set up a Multi-Step Analysis.
A can write the whole required boundary conditions in the first configuration and activate them only at the required step.
I have a Custom Step content at the first Step *RESTART,WRITE and a custom model definition with *RESTART,READ at the second.

My idea was to run the first configuration (Step1) and then run the second configuration (Step2) with a previous hand modification of the *.rout to *.rin file.

I’m finding some issues.

-First configuration (Step1) writes a file Step1_Mecway_Step_1.rout but second configuration (Step2) search for Step1_Mecway_Step_2.rin. Not a big deal as I can adjust the name of the file before running Step 2.
-*RESTART,READ is not working properly. I guess the problem is that it is set up inside a “custom model definition” and the card is written at the end of the INP.
-I’m in need of independent generation of Custom Cards and Custom Step contents too in the same way as I can introduce multiple Modify Keyword.

I think that if custom cards were added at the proper position the actual New configuration tool could open the door to Mecway being capable of multistep analysis.

¿Am I right or does someone anticipate some other evident drawbacks?

Victor

Wow that's really pushing the boundaries.

I'm not sure about multiple custom model definition and custom step contents because if you unsuppress more than one in a configuration, Mecway has to make a decision about the order they're applied in. It wouldn't be an issue for your use case but needs to be somehow made obvious and configurable.

Custom model definition gets put immediately before the first automatically generated *STEP section, not at the very end.

Perhaps as a dirty workaround, define one step using custom model definition as:

*STEP
...
*END STEP

and the other as custom step contents as:

*END STEP
*STEP
...

Mishal

Hi @disla, this really sounds amazing. I have done this sort of stuff on Strand7, didn't even know that it would be a possibility on Mecway. It would be really nice if you could share a simplified model for the case when you have it up and running.

disla

Custom model definition gets put immediately before the first automatically generated *STEP section

I think that's the issue. *RESTART,READ must be at the very beginning of the inp itself not the *step block.

didn't even know that it would be a possibility on Mecway

you can insert aditional steps by custom cards. My suggestion was to benefit from MECWAY easy way of writing the card for you . If you need an OP=NEW for example it makes you write all the new BC by hand so you lose all the advantages that Mecway provides when translating instructions into an inp file.

Sergio

I was a big fan of multistep analysis (as I came from Abaqus), but after a lot of experiments (writing manually cards for the second, third.. steps) I have found that I can make all of my multistep simulations in one step using an appropiate Time Period and then tabulate the loads or displacements, in this way all can be done in the Mecway GUI. Is the same for the *RESTART card, a lot of expermients to make it run, to find out that result file are not combined with the initial ones... so was a waste of time to me. Even *SUBMODEL, the time that I need to understand (because is not used everyday), validate and prepare a model would be the same as making a mesh refinement and run the whole model directly.

What kind of simulations are you running that needs multistep that cannot be run with tabulated loads/displacements?

disla

Hi Sergio ,

Mainly change BC. Can’t find the way to introduce OP=NEW inside the same step.

Sergio

Are you tring to remove an impossed displacement? Can you apply a reverse displacement in place?

disla

It is more a release than a return to the initial position.

Sergio

Would be interesting to see the problem, can you share it?

disla

Not really but it’s easy to understand.
My model is considerably pre-heated before operation. Once heated, It is intended to work on that temperature range it’s whole life.
The expansion process is controlled as much as possible with lateral guides that help to reduce off centering.
Before operation, guides must be removed as they have done their job. I want my model completely free before operation loads take effect. I can set up contacts if there is no option but I would like to avoid it.

Sergio

Without seeing the model, I would use guides (modelded and include contact) and move away before main loading.

disla

I think I don't have other option now.
Thank you Sergio.