# Buckling Analysis **URL:** \ **Category:** General Questions\ **Created:** [January 30, 2024, 10:04am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463 "2024-01-30T10:04:12Z")\ **Posts on this page:** 15\ **Page:** 2
**Author:** ![lucas\_bueno](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/lucas_bueno/32/1168_2.png) [@lucas\_bueno](https://prepomax.discourse.group/u/lucas_bueno)\ **Post date:** [January 30, 2024, 10:52pm UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/21 "2024-01-30T22:52:59Z")
> [@FEAnalyst](#): > > There are even PRs with solution proposals. … which are still not merged even after a year or so… ---
**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:** [January 30, 2024, 11:12pm UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/22 "2024-01-30T23:12:01Z")
Some were reviewed and closed (after solving the related issues) by Guido shortly before the release of 2.21 but there are still quite a few left. But it’s the number of issues that’s really worrying here. Hopefully, he will find some time to resolve at least a few of them. Especially those that are nasty bugs, not just known limitations. ---
**Author:** ![jsarocena](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/jsarocena/32/2531_2.png) [@jsarocena](https://prepomax.discourse.group/u/jsarocena)\ **Post date:** [January 31, 2024, 1:18am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/23 "2024-01-31T01:18:17Z")
> [@Agazzotti](#): > > The Eulerian critical load is equal to P=E_J_3.1415^2/(4\*L^2) = 470’437.10 N (47’974.41 kgf). Carrying out the calculation with load P the result is equal to Buckling Factor = 1.02 and therefore substantially correct. By applying a load equal to P1= 980’665 N (100’000 kgf) the result is equal to Buckling Factor = 4.374 Very good observation. I don’t even think of it, such kind of observation. Thanks a lot for sharing and also for everyone for keep sharing a very helpful information and observation. ---
**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:** [January 31, 2024, 9:47am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/24 "2024-01-31T09:47:25Z")
> [@FEAnalyst](#): > > The number of unresolved bugs is growing and it might be a good time to send another reminder to Guido I am aware that although some of the bug reports have not been cleaned up and reclassified as solved, they have been worked on. Specifically I reported a problem with the Courant number in explicit and saw some changes in the code about it. It is possible that this is just a cosmetic issue or a re-classification of the report as resolved. Something like what Matej does from time to time that reviews all the posts and closes the ones that are solved. What do you think would be the kindest way to ask Don Guido about the current status of the bug list? I don’t want to be a nuisance or overlap with other users. ---
**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:** [January 31, 2024, 10:08am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/25 "2024-01-31T10:08:49Z")
> [@ANYS](#): > > What do you think would be the kindest way to ask Don Guido about the current status of the bug list? I usually just e-mail him asking to take a look at some issues of particular importance (especially when there are several such urgent issues waiting to be resolved). It seems that he doesn’t mind those remainders and always provides a comprehensive answer. I may contact him again soon as I wanted to talk with him about the issues with rigid body constraints and initial velocity in explicit dynamics with 2D/shell elements, among the others. I would also mention other bugs like the one discussed here. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [January 31, 2024, 10:47am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/26 "2024-01-31T10:47:17Z")
i do simple recreate the model, and it seems all the solver (Spooles, PaStiX, Pardiso) given consistent and identical results. ![2024-01-31 17_37_04-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/8/80eea3620228dd1c191b1578ef3507530fbcf2dd.png) p.s unit load is -1000N and quadratic hexahedral element (C3D20R) being used. > [@Gunnar](#): > > I mean there is a problem with Spooles when using more than two processors. i heard about the problem of Spooles MT in frequency and buckling analysis, in this case a distribution from CFTurbo FEA probably can solve the problems. ---
**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:** [January 31, 2024, 10:54am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/27 "2024-01-31T10:54:30Z")
Yes, it can give good results like when the load is 1 N or 470437.10 N (the OP’s case). The problems start when the load is larger than the buckling load and the issues might be mesh-dependent as well. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [January 31, 2024, 11:06am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/28 "2024-01-31T11:06:48Z")
if i can remember correctly, this problem has been fixed by Victor from Mecway (many thanks). Simple re-testing with load of -500000N for the problem cases above, still provide consistent result for all solver here. ![2024-01-31 17_58_28-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/1/121fb53aa73d2447682bf79582b8ccd5f235d7b6.png) ---
**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:** [January 31, 2024, 11:12am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/29 "2024-01-31T11:12:51Z")
I reported the issue here: [First buckling mode skipped when applied load is much bigger than buckling load · Issue #74 · Dhondtguido/CalculiX · GitHub](https://github.com/Dhondtguido/CalculiX/issues/74) > [@synt](#): > > Simple re-testing with load of -500000N for the problem cases above, still provide consistent result for all solver here. Apparently because it’s still close to buckling load. 980665 N causes problems. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [January 31, 2024, 11:42am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/30 "2024-01-31T11:42:42Z")
> [@FEAnalyst](#): > > Apparently because it’s still close to buckling load. 980665 N causes problems. i can confirm. It seems load magnitudes still can be greater than buckling loads until two times, out of these ranges the lowest factor did not report well and it jumps to next probable buckling shapes. ![2024-01-31 18_33_42-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/4/4d2fd9f5e4dcb15d5cbf66eef5c3faf7e82355bc.png) ---
**Author:** ![andrea.starnini](https://avatars.discourse-cdn.com/v4/letter/a/46a35a/32.png) [@andrea.starnini](https://prepomax.discourse.group/u/andrea.starnini)\ **Post date:** [May 31, 2024, 8:31pm UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/31 "2024-05-31T20:31:00Z")
I’m studying a reinforcements for a column against buckling. For this aim I started a buckling analysis of a simple HEB200 column using RBE on the base and on the head of the column. I found a strange behaviour of the default CCX solver on Prepomax: With a compression load of 1 kN the results are compatible with Euler theory and the first buckling mode is relative to instability around the weak axis, which is obvious. Augmenting the compression load to 1000 kN the first buckling mode disappear, maybe because is less than 1. I think that’s could be dangerous because buckling factors less than 1 are neglected. Are there some parameters that I neglected? ![immagine](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/0/06e8e322655f580c7213f8e45d06c02a87cf7c50.png) ---
**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:** [May 31, 2024, 10:32pm UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/32 "2024-05-31T22:32:16Z")
Check this: [First buckling mode skipped when applied load is much bigger than buckling load · Issue #74 · Dhondtguido/CalculiX · GitHub](https://github.com/Dhondtguido/CalculiX/issues/74) ---
**Author:** ![andrea.starnini](https://avatars.discourse-cdn.com/v4/letter/a/46a35a/32.png) [@andrea.starnini](https://prepomax.discourse.group/u/andrea.starnini)\ **Post date:** [June 1, 2024, 4:13am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/33 "2024-06-01T04:13:38Z")
Ok, but I don’t encountered this problem with CCX 2.20 and 2.21. ![immagine](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/d/db6046666fcd96e0be5c66fcd01f587a42ca570e.png) ---
**Author:** ![Victor](https://avatars.discourse-cdn.com/v4/letter/v/3e96dc/32.png) [@Victor](https://prepomax.discourse.group/u/Victor)\ **Post date:** [June 1, 2024, 5:14am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/34 "2024-06-01T05:14:09Z")
1 isn’t a hard limit, and it can produce results a little lower than that. ---
**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:** [June 1, 2024, 6:34am UTC](https://prepomax.discourse.group/t/buckling-analysis/1463/35 "2024-06-01T06:34:53Z")
It’s highly mesh- and solver-dependent too but the problem is still there in most cases. [Previous page](https://prepomax.discourse.group/t/buckling-analysis/1463.md?page=1)