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No Mass Matrix When Using DMIGPCH

Hi,

I ran DMIGPCH to extract the mass and stiffness matrix for the attached file. The result only extracted a stiffness matrix. There does not seem to be in input to request a mass matrix, so I assume it should be outputted automatically. Can anyone explain why I might not be getting one? Unable to attach the .pch due to huge size (350 mb).

Thanks

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Robert Lawson

It seems like this should work as you have it, but it doesn't. It must be being a bit lazy (or efficient?) about creating a mass matrix if it doesn't need to.

Add an ANALYSIS=MODES and METHOD=? to your case control, and then an EIGRL to your bulk data. Then it will give you a MAAX.

Crashphys

Thank you for the suggestion. I'll give it a try, but my solution was eventually to just convert to a NASTRAN model (very easy) and use that. Most open source code that exists to interpret it follows NASTRAN format anyway...

David Vásquez

It seems like this should work as you have it, but it doesn't. It must be being a bit lazy (or efficient?) about creating a mass matrix if it doesn't need to.

Add an ANALYSIS=MODES and METHOD=? to your case control, and then an EIGRL to your bulk data. Then it will give you a MAAX.

Hi Robert, can you explain me how to add analysis and method like you said, i was looking but i didn't find where are this options.