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How to generate a superelement with bolt preload in Optistruct?

Jin1

I have tried the following steps, but encountered issues. Here are my steps:

① In the first load step, I used Non-linear static analysis for bolt preload and successfully computed the results.
② Then, I added a subsequent analysis step using a generic analysis step, referenced the corresponding card in CMSMETH, and used statsub(PRELOAD) to reference the preload analysis step. The preload calculation worked normally, but a prompt indicated that Param,IR4NLCOM needed to be enabled.
③ However, when running the second analysis step, an error occurred: "Specified load case number 1 out of allowed range (1-0)".

My goal is to obtain the stiffness changes after preload, consolidate them, and generate a superelement.

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Accepted answers

solon

Yes, it is reasonable. This way you will include the pretension effect (stiffening of the structure) in the super element.

All comments

solon

Please, share the model.

Jin1

This is my model. It's very strange. I couldn't use the previous model, but I remodeled it, and it seems to have calculated successfully. Can you help me check if there are any other problems? Is it reasonable to generate superelements in this way?

bolt.fem

solon

Yes, it is reasonable. This way you will include the pretension effect (stiffening of the structure) in the super element.