# Is there a way to output B Matrix using input deck cards **URL:** \ **Category:** Uncategorized\ **Created:** [May 30, 2024, 5:29am UTC](https://calculix.discourse.group/t/is-there-a-way-to-output-b-matrix-using-input-deck-cards/2291 "2024-05-30T05:29:55Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Anoop\_ng](https://avatars.discourse-cdn.com/v4/letter/a/4491bb/32.png) [@Anoop\_ng](https://calculix.discourse.group/u/Anoop_ng)\ **Post date:** [May 30, 2024, 5:29am UTC](https://calculix.discourse.group/t/is-there-a-way-to-output-b-matrix-using-input-deck-cards/2291/1 "2024-05-30T05:29:55Z")
Hi, 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? Thanks!! Anoop ---
**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\ **Post date:** [May 30, 2024, 7:22am UTC](https://calculix.discourse.group/t/is-there-a-way-to-output-b-matrix-using-input-deck-cards/2291/2 "2024-05-30T07:22:43Z")
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. ---
**Author:** ![Anoop\_ng](https://avatars.discourse-cdn.com/v4/letter/a/4491bb/32.png) [@Anoop\_ng](https://calculix.discourse.group/u/Anoop_ng)\ **Post date:** [May 30, 2024, 7:26am UTC](https://calculix.discourse.group/t/is-there-a-way-to-output-b-matrix-using-input-deck-cards/2291/3 "2024-05-30T07:26:05Z")
Thank you @Calc_em for the response. ---
**Author:** ![jbr](https://avatars.discourse-cdn.com/v4/letter/j/ecccb3/32.png) [@jbr](https://calculix.discourse.group/u/jbr)\ **Post date:** [May 31, 2024, 12:58am UTC](https://calculix.discourse.group/t/is-there-a-way-to-output-b-matrix-using-input-deck-cards/2291/4 "2024-05-31T00:58:13Z")
Keep in mind that the B matrix will be based on solid elements, not 1D or 2D simplifications. ---
**Author:** ![vicmw](https://avatars.discourse-cdn.com/v4/letter/v/6de8d8/32.png) [@vicmw](https://calculix.discourse.group/u/vicmw)\ **Post date:** [June 1, 2024, 11:04am UTC](https://calculix.discourse.group/t/is-there-a-way-to-output-b-matrix-using-input-deck-cards/2291/5 "2024-06-01T11:04:43Z")
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. ---
**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\ **Post date:** [June 1, 2024, 3:36pm UTC](https://calculix.discourse.group/t/is-there-a-way-to-output-b-matrix-using-input-deck-cards/2291/6 "2024-06-01T15:36:06Z")
I think that the OP means the strain-displacement matrix commonly used in literature when forming the stiffness matrix. ---
**Author:** ![Anoop\_ng](https://avatars.discourse-cdn.com/v4/letter/a/4491bb/32.png) [@Anoop\_ng](https://calculix.discourse.group/u/Anoop_ng)\ **Post date:** [June 3, 2024, 10:10am UTC](https://calculix.discourse.group/t/is-there-a-way-to-output-b-matrix-using-input-deck-cards/2291/7 "2024-06-03T10:10:32Z")
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? ---
**Author:** ![JuanP74](https://avatars.discourse-cdn.com/v4/letter/j/b5a626/32.png) [@JuanP74](https://calculix.discourse.group/u/JuanP74)\ **Post date:** [June 3, 2024, 5:06pm UTC](https://calculix.discourse.group/t/is-there-a-way-to-output-b-matrix-using-input-deck-cards/2291/8 "2024-06-03T17:06:27Z")
Not sure is that easy, I’d start reading carefully chapter 10 of the manual, then try to pull the thread from here… ![imagen](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/e/e6b2c2df6b560294604e677d71c42369e22c836d.png)