# Step Time reduction in case of convergence failure

**URL:** <https://prepomax.discourse.group/t/step-time-reduction-in-case-of-convergence-failure/2551>\
**Category:** General Questions\
**Created:** [March 19, 2025, 11:34am UTC](https://prepomax.discourse.group/t/step-time-reduction-in-case-of-convergence-failure/2551 "2025-03-19T11:34:33Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![ANYS](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/anys/32/7737_2.png) [@ANYS](https://prepomax.discourse.group/u/ANYS)\
**Post date:** [March 19, 2025, 11:34am UTC](https://prepomax.discourse.group/t/step-time-reduction-in-case-of-convergence-failure/2551/1 "2025-03-19T11:34:33Z")

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Hi,

I’m experiencing an unexpected response from the solver. I have setup a NLGEOM quasi-static analysis which I know it must fail at around TOT time = 0.158600E+01 sec.  
The steeped default process passes through 0.150000E+01 sec to 0.160000E+01 sec , fails to converge as expected but…, instead of reducing the step time to try something in between (0.150000E+01 sec. , 0.160000E+01 sec.) it keeps trying to solve for the same value again and again. My external load is ramped according to a simple linear amplitude (0,0) & (1,1).  
My goal is to get the final picture as close as possible to the failure.  
I don’t recall this behavior when using Mecway. Is there something I should set up in Prepomax to allow a Step Time reduction in case of convergence failure.

 ![screenshot.58](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/0/0fb72b743b44e87938346db1767b03592a8c9a8e.png)  
 ![screenshot.57](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/c/ccf967460223d46dbf2891e837b64280f1ab4424.png)

Thanks

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [March 19, 2025, 1:15pm UTC](https://prepomax.discourse.group/t/step-time-reduction-in-case-of-convergence-failure/2551/2 "2025-03-19T13:15:39Z")

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It tried reducing the increment size:

 ![status](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/6/6a53d5b3a9668312342dcf29f313d3e72450d168.png)

but those were failed attempts and the step/total time wasn’t updated.

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<div class="post-metadata">

**Author:** ![ANYS](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/anys/32/7737_2.png) [@ANYS](https://prepomax.discourse.group/u/ANYS)\
**Post date:** [March 19, 2025, 2:08pm UTC](https://prepomax.discourse.group/t/step-time-reduction-in-case-of-convergence-failure/2551/3 "2025-03-19T14:08:18Z")

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Thanks FEAnalyst. I 'm not sure to understand the monitor.

I have set up a direct squeme with increments of 0.05 and it has pass 1.55 sec.  
That probably means the value shown in the monitor is a success step time?¿?. Maybe it is attempting to go further that 1.6.¿?¿

 ![screenshot.59](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/6/63837cbff11659bb726ae36fa2ddc80f089aba8a.png)

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<div class="post-metadata">

**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [March 19, 2025, 3:11pm UTC](https://prepomax.discourse.group/t/step-time-reduction-in-case-of-convergence-failure/2551/4 "2025-03-19T15:11:40Z")

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> [@ANYS](#):
>
> That probably means the value shown in the monitor is a success step time?

Something like this - it only updates step/total time when it converges for that time. This is well visible in the case of analyses that fail from the start (screenshot from Abaqus):

 ![image](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/f/f4ca76f6cbb8173f0e45075c90c5321014924b38.png)

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<div class="post-metadata">

**Author:** ![ANYS](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/anys/32/7737_2.png) [@ANYS](https://prepomax.discourse.group/u/ANYS)\
**Post date:** [March 19, 2025, 6:30pm UTC](https://prepomax.discourse.group/t/step-time-reduction-in-case-of-convergence-failure/2551/5 "2025-03-19T18:30:19Z")

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Now it’s clearer to me, thank you very much. Monitor only update the value when it has converged. I thought monitor was showing me the next attempt not the recent success.

NOTE: Now I’m finding another unexpected result. I have switch to mortar as contact method to see how it performs compared to Surface to Surface.  
Now the iteration process reduces the overall time step close to the failure time step automatically as I would expect to a value of 0.157500E+01 closer to the expected result.  
After that point, contact brakes , but analysis keeps going without failing ?¿?¿. Results are nonsense from that point.

 ![screenshot.60](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/f/f159212dab871074919335359eb5348da5ab0a77.png)
