topic Re: no convergence of nonlinear problem in Robot Structural Analysis Forum

no convergence of nonlinear problem

Anonymous — Thu, 14 Mar 2013 10:24:16 GMT

Hello,

I have this 3D model which I doing an analysis for.

Before adding WIND2 (lateral) load case, I had no problems with the calculations. However, when WIND2 loads were added, I received the analysis warning/error "no convergence of nonlinear problem" . I am not very familair with non-linear analysis so I do not really know what is going on.

Also, I have used tension only elements to act as cables. Is this correct?

Your help will be appreciated.

Re: no convergence of nonlinear problem

Rafal.Gaweda — Thu, 14 Mar 2013 10:37:51 GMT

Correct settings

Re: no convergence of nonlinear problem

Anonymous — Thu, 14 Mar 2013 10:50:25 GMT

Thank you Rafal for the prompt reply.

May I ask why this problem occured only when lateral loads were added?

Also, it is correct to use tension only elements to act as cables in the model?

Re: no convergence of nonlinear problem

Rafal.Gaweda — Thu, 14 Mar 2013 12:02:30 GMT

May I ask why this problem occured only when lateral loads were added?

Usually wind or snow or temperature does not act on weightless structure it means vertical load are required to stabilize structure

Also, it is correct to use tension only elements to act as cables in the model?

It depens on what simplification you can use creating model.

But if you are not concerned about results in "cables" - you can.

Re: no convergence of nonlinear problem

t.sautierr — Sat, 08 Nov 2014 09:10:38 GMT

Never thought about using tension element instead of cables when I need to design cables 🙂 the calculation element behind are the same : unidirectionnal stiffness and releases at the end ? There would be no problem when using P delta analysis for example?

Re: no convergence of nonlinear problem

jokiller70 — Tue, 11 Nov 2014 10:03:53 GMT

Any way to set this from API?

Re: no convergence of nonlinear problem

Rafal.Gaweda — Wed, 12 Nov 2014 07:38:14 GMT

Any way to set this from API?

Using RobotNonlinearAnalysisParams

Re: no convergence of nonlinear problem

krabadavar — Mon, 24 Aug 2015 11:39:35 GMT

Hello

I have the same problem with no convergence.

I know that the model has other errors because of the

nonsupported claddins on beams, but it gives some results

whitout a nonlinear support (uplift).

The model is attached here

http://www.filedropper.com/model

I tried also to put the rest of the loads to be auxiliary.

Regards,

Re: no convergence of nonlinear problem

Rafal.Gaweda — Mon, 24 Aug 2015 14:34:34 GMT

First of all I would start with correcting model
1. Walls should be connected with other walls or slabs - see panels 7594to7597 7627to7630
and walls starting with panels 8266 8267 8269
2. Claddings are not the slabs so I guess you should use ordinary panels or diaphragms
3. Bars not connected with model, see nodes : 783 784 810 811 23403 23404
4. Mesh model properly without kinematic links

Re: no convergence of nonlinear problem

krabadavar — Tue, 25 Aug 2015 05:10:34 GMT

Hi Rafal,

Thanks for the answer I'll try to correct what you said . Isn't possible also wall to sit on beams only.

Because this is the case that I have. I missed some beams in this big model

but I'll add them now.

Regards,

Milko

Re: no convergence of nonlinear problem

Rafal.Gaweda — Tue, 25 Aug 2015 07:25:51 GMT

Isn't possible also wall to sit on beams only.

Of course it is possible.

Re: no convergence of nonlinear problem

krabadavar — Thu, 03 Sep 2015 11:51:41 GMT

Hello again,

I've changed all the claddings to be slab 30cm in concrete.

I repaired also the errors. And stil it doesn't calculate with the uplift.

Also I'm trying to export it to Revit and after 3 hours thinking(aproximately)

It gives "Unknown runtime error". I saw in the other forums that this

could happened under windows 10, but this is not the case. I have win 8.

Any ideas?

Re: no convergence of nonlinear problem

Rafal.Gaweda — Thu, 03 Sep 2015 12:00:14 GMT

File please.

Re: no convergence of nonlinear problem

Rafal.Gaweda — Thu, 03 Sep 2015 12:10:12 GMT

Have you copied files as described here:
http://forums.autodesk.com/t5/robot-structural-analysis/robot-2016-and-windows-10-compatibility-update-from-win7-64bit/m-p/5769233#M36756 ?

Re: no convergence of nonlinear problem

krabadavar — Fri, 04 Sep 2015 05:14:13 GMT

Hello again,

Yes I've copied the .dll files from the other forum under the location shown there.

The model is here:

http://www.filedropper.com/mall-model029

Regards,

Milko

Re: no convergence of nonlinear problem

Rafal.Gaweda — Fri, 04 Sep 2015 12:53:33 GMT

No luck 😞
Developers have to look at it closer.

Re: no convergence of nonlinear problem

Rafal.Gaweda — Fri, 04 Sep 2015 15:21:37 GMT

If you replace sections on bars

1to6 16to18 8 9 58to64 93to102By3 104to111 124to130 137to139 171to176 247to249 557to559 562to571By3 567to624By19 574to576 581to593By3 597to599 657to660 20 23 43 47 54 95 98 121 134 135 142 151 183 190 191 208 209 212 217 218 223 245 293 294 570 582 589 595 603 631 634 638 646 647 652 664to668 702to706 766to771 783to786 804to810 812to814 828to833 838to840 873to875 881to884 918to922 1218to1335By39 1228to1348By40 671 682 686 687 690 696 698 700 754 755 775 777 779 780 793 795 823 835 836 850 855 858 860 862 863 879 934 935 1194 1195 1198 1210 1214 1301to1307By2 1311to1368By19 1315to1325 1337to1339 1354to1357 1361to1364 1382to1394By4 1400to1403 1230 1235 1237 1255 1258 1291 1300 1312 1351 1375 1377 1384 1389 1393 1416to1419 1431to1435 1437to1443 1448to1451 1461to1463 1466to1471 1475to1488 1500to1503 1627to1634 1643to1646 1648to1692By11 1427 1428 1445 1446 1454 1455 1457 1459 1473 1491 1506 1511 1512 1590 1591 1598 1604 1617 1620 1622 1623 1638 1640 1650 1652 1662 1665 1666 1693 2269 2703 2712 2713 2747 2752to2759 3307to3309 4720to4723 4726to4737 4743to4754 7397to7400 8635to8637 8642to8644 2768 2775 2776 2778 2781 3033 3185 3189 3191 3192 3196 3210 3214 3215 3224 3232 3239 3267 3268 3271 3272 3276 3282 3287 3289 3298 3305 3912 4710 4716 4717 4740 4741 4777 6957 6958 6969 7126 7161 7163 7219 7264 7265 7419 7420 7512 8603 8623 8624 8626 8627 8639 8640 8663 8664 8673to8680 8685to8690 8697to8699 8701to8705 8707to8725 8727to8742By5 8745to8750 8752to8754 8682 8731 8736 8740 8743 8759 8761to8794By11 8766 8776to8780 8792 8799 10755 10757to10765 10768 10770 10771 10773 10778 10790to10805 10808 10809 10817 10832 10833 10917 10918 10943 11030 11054 11065 11070 11083 11092to11094 11096 11097to11118By7 11113to11115 11119

by standard Rectangular sections it should work

Revit 2016 file here: http://we.tl/Txp7M1ptlz

Re: no convergence of nonlinear problem

krabadavar — Wed, 09 Sep 2015 12:14:42 GMT

Thanks for the model ,

For the time being I use Revit 2015 but we also succeeded meanwhile.

I found that the error was on level GMH only. And yes - repaced some of the sections there with different and succeeded.

Also some of the reversed T-sections were defined as a column sections and then used as beam sections (just a lazyness not to change local axes later - don't kill me ). I thought this causes errors but we found that this don't return errors.

Regards,

Milko

Re: no convergence of nonlinear problem

tofighXR9EB — Thu, 08 Jul 2021 12:12:29 GMT

Hi Rafal

Thank you for sharing the information. I have faced other warnings after changing the analysis type to what you advised. It says that non-linear analysis cases cannot be included in code combinations.

I greatly appreciate it if you could advise, please.

Regards

Tofigh