# Model not reaching convergence

**URL:** <https://forum.itascainternational.com/t/model-not-reaching-convergence/1595>\
**Category:** PFC\
**Created:** [July 22, 2024, 6:38pm UTC](https://forum.itascainternational.com/t/model-not-reaching-convergence/1595 "2024-07-22T18:38:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![paudyalp11](https://avatars.discourse-cdn.com/v4/letter/p/9fc348/32.png) [@paudyalp11](https://forum.itascainternational.com/u/paudyalp11)\
**Post date:** [July 22, 2024, 6:38pm UTC](https://forum.itascainternational.com/t/model-not-reaching-convergence/1595/1 "2024-07-22T18:38:45Z")

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Hello everyone,

I am currently trying to calibrate a direct shear test. I am using the ‘rrlinear’ model for ball-ball contact and the linear model for ball-wall contact. I am having trouble settling the balls before the consolidation phase of the test, and the model does not seem to converge. I suspect this has something to do with big overlaps during ball generation, but I can’t put a finger on on what I would need to change to avoid this issue. I have attached my data file to this message and would appreciate someone taking a look.  
[dst\_algorithm.dat](https://forum.itascainternational.com/uploads/short-url/7kqPnIGpy7ZrN0Li3qX5IRXEx51.dat) (3.7 KB)

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**Author:** ![dblanksma](https://avatars.discourse-cdn.com/v4/letter/d/858c86/32.png) [@dblanksma](https://forum.itascainternational.com/u/dblanksma)\
**Post date:** [July 24, 2024, 7:04pm UTC](https://forum.itascainternational.com/t/model-not-reaching-convergence/1595/2 "2024-07-24T19:04:03Z")

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Hello @paudyalp11,  
In this case the porosity value in the **ball distribute** command is too high (0.41). You need to reduce this value. I used 0.35 and the model solved to equilibrium with a **model solve ratio-average 1e-5**.