no convergence of nonlinear problem

[Anonymous]

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. 

[Rafal.Gaweda · Accepted solution]

Correct settings

[Anonymous]

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? 

[Rafal.Gaweda]

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.

[t.sautierr]

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?

[jokiller70]

Any way to set this from API?

[Rafal.Gaweda]

Any way to set this from API?

---

Using   RobotNonlinearAnalysisParams

[krabadavar]

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,

[Rafal.Gaweda]

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

[krabadavar]

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

[Rafal.Gaweda]

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

Of course it is possible.

[krabadavar]

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?

[Rafal.Gaweda]

File please.

[Rafal.Gaweda]

Have you copied files as described here:
http://forums.autodesk.com/t5/robot-structural-analysis/robot-2016-and-windows-10-compatibility-upda... ?

[krabadavar]

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

[Rafal.Gaweda]

No luck 😞
Developers have to look at it closer.

[Rafal.Gaweda]

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

[krabadavar]

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

[tofighXR9EB]

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