# Element Removal in CalculiX for Fracture **URL:** \ **Category:** Uncategorized\ **Created:** [March 31, 2021, 5:28pm UTC](https://calculix.discourse.group/t/element-removal-in-calculix-for-fracture/520 "2021-03-31T17:28:33Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![bsnow](https://avatars.discourse-cdn.com/v4/letter/b/f4b2a3/32.png) [@bsnow](https://calculix.discourse.group/u/bsnow)\ **Post date:** [March 31, 2021, 5:28pm UTC](https://calculix.discourse.group/t/element-removal-in-calculix-for-fracture/520/1 "2021-03-31T17:28:33Z")
I’m currently looking into converting some Abaqus fracture simulations (Charpy Impact & Compact Tension tests) into Calculix. I’m currently using an Abaqus VUMAT that has a flag which deletes elements in the mesh once the material damage reaches a certain amount (specifying the state variable # corresponding to deletion as \*Depvar, Delete=#), but I am struggling to determine if Calculix has a similar capability. Any suggestions would be greatly appreciated. ---
**Author:** ![jbr](https://avatars.discourse-cdn.com/v4/letter/j/ecccb3/32.png) [@jbr](https://calculix.discourse.group/u/jbr)\ **Post date:** [March 31, 2021, 6:07pm UTC](https://calculix.discourse.group/t/element-removal-in-calculix-for-fracture/520/2 "2021-03-31T18:07:34Z")
I’m not sure if this can work but maybe the `*MODEL CHANGE` card? Page 526 of ccx 2.17 manual. > With this option, one can activate or deactivate elements and contact pairs. Furthermore, one can turn the mechanical strain in existing elements into residual strain at the start of a new step. Not sure if can be combined with the `*DEPVAR`s. ---
**Author:** ![bsnow](https://avatars.discourse-cdn.com/v4/letter/b/f4b2a3/32.png) [@bsnow](https://calculix.discourse.group/u/bsnow)\ **Post date:** [March 31, 2021, 8:00pm UTC](https://calculix.discourse.group/t/element-removal-in-calculix-for-fracture/520/3 "2021-03-31T20:00:46Z")
That is interesting but from further reading I think \*MODEL CHANGE wouldn’t be able to dynamically remove elements. After reading some of the Abaqus documentation on element deletion however, I think I may be able to work around that though by just setting all of the stresses to zero in the element once the damage criterion is met, so I’ll just have to modify the user material a bit. Thanks for the quick response and help. ---
**Author:** ![jbr](https://avatars.discourse-cdn.com/v4/letter/j/ecccb3/32.png) [@jbr](https://calculix.discourse.group/u/jbr)\ **Post date:** [April 1, 2021, 2:34am UTC](https://calculix.discourse.group/t/element-removal-in-calculix-for-fracture/520/4 "2021-04-01T02:34:40Z")
You are welcome 🙂. Sounds like a good workaround. ---
**Author:** ![Uom0](https://avatars.discourse-cdn.com/v4/letter/u/8797f3/32.png) [@Uom0](https://calculix.discourse.group/u/Uom0)\ **Post date:** [June 16, 2021, 6:51pm UTC](https://calculix.discourse.group/t/element-removal-in-calculix-for-fracture/520/5 "2021-06-16T18:51:02Z")
Just be aware that if you reduce the stiffness to 0, you could get an ill conditioned stiffness matrix (one could use for instance 1e-6). Furthermore, the elements are still populated in such a matrix and might cause some troubles if not removed from the analysis. Anyways, just try. ---
**Author:** ![bsnow](https://avatars.discourse-cdn.com/v4/letter/b/f4b2a3/32.png) [@bsnow](https://calculix.discourse.group/u/bsnow)\ **Post date:** [June 17, 2021, 10:03pm UTC](https://calculix.discourse.group/t/element-removal-in-calculix-for-fracture/520/6 "2021-06-17T22:03:40Z")
That’s a good point, thanks. Currently I am using Explicit Dynamics though, so it shouldn’t be too big of a deal.