I’m relatively new to Calculix and currently working on solving a static linear elastic problem. I’ve been trying to find a way to output the element stiffness matrix to a result file. Could someone please guide me on whether this is possible and, if so, provide instructions on how to achieve this?

I’d recommend *SUBSTRUCTURE GENERATE and *SUBSTRUCTURE MATRIX OUTPUT for earlier versions of CCX rather than *FREQUENCY, all are valid approaches but maybe these are more fitted to the request.

Conversely, I would recommend *FREQUENCY, SOLVER=MATRIXSTORAGE. The stiffness matrix generated by it should be the same as the one used in linear static analysis. Matrices used in substructures can be defined in a different manner, specific to superelements. This applies to both matrix file syntax and concepts (retained nodes in substructures, limitations of substructures and so on).

You will get a global stiffness matrix this way. Abaqus has a *MATRIX GENERATE keyword with an optional ELEMENT BY ELEMENT parameter to generate local matrices.

It produces a global stiffness matrix unless you make a substructure consisting of just a single element. Still, I would be careful with this approach.