Is there a way to output B Matrix using input deck cards


Is it possible to output the B matrix to a result file using input deck cards in CalculiX, similar to how we can output the stiffness matrix using the *FREQUENCY card?


Only the stiffness and mass matrcies can be outputted this way. But since CalculiX is open-source, maybe you could find a way to extract it by looking at the source code where it’s computed.


Thank you @Calc_em for the response.

Keep in mind that the B matrix will be based on solid elements, not 1D or 2D simplifications.

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Do you mean the composite coupling matrix? I don’t think CCX has that because the composites are solids with stress, rather than shells with force and moment per unit width.

I think that the OP means the strain-displacement matrix commonly used in literature when forming the stiffness matrix.


Can anyone identify the file or subroutine within the CalculiX source code where the B-matrix and the constitutive matrix (material property matrix) are computed?

Not sure is that easy, I’d start reading carefully chapter 10 of the manual, then try to pull the thread from here…