Questions tagged [buckling]
The buckling tag has no usage guidance.
51
questions
3
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2answers
102 views
Do yielded columns buckle?
A sufficiently slender column will fail under compression below yield stress by bowing, releasing it's axial elastic strain. This is called buckling. Depending on the slenderness of the column, the ...
1
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1answer
33 views
Shear capacity according to eurocode , when to use which equation
I am looking at eurocode to calculate shear capacity, and under section "6.2.6 Shear", there are two different shear checks:
Eq 6.18
Eq 6.19
When there is no torsion we can use equation 6....
0
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0answers
50 views
Why does figure 2 and 6 deform differently from the other shapes?
I am doing a linear buckling analysis on all the structures you see below, they are subjected to compression load in the x-axis as indicated by the arrow. You can see all structures beside 2 and 6 ...
0
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0answers
27 views
How do I find the buckling strength?
I am running something called cell periodicity study in comsol, which finds the material properties of a model. It is done by applying a uniaxial compression load, and performing a nonlinear buckling ...
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0answers
44 views
Do these linear vs nonlinear buckling plots make sense?
I am doing linear buckling analyses (where everything is linear), and nonlinear buckling analyses where you have nonlinear geometry enabled and nonlinear material behavior (hyperelastic material). ...
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0answers
19 views
Why do we need to have perturbation in our system to do buckling analysis? [closed]
Do we need it for both linear and nonlinear system?
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0answers
39 views
(Follow up) Can a thicker model giver a lower critical buckling load?
I present three seperate models with thickness of t = 0.005m, 0.01m and 0.025m respectively, all have a forced displacement of -0.01m in the x-direction, and fixed on the other end. As you can see the ...
1
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2answers
65 views
Can a thicker model have a lower critical buckling load?
I perform a linear buckling analysis for two similar geometries, where one model has thickness t = 0.01 m, and the other has thickness t = 0.035 m. Otherwise everything is exactly the same. The ...
1
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0answers
29 views
How is a linear buckling test supposed to look like?
If I had a cube like object; would this be a good way to set up a linear buckling analysis?
https://imgur.com/a/ltMDTlT
And no other forces or boundary conditions
0
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0answers
34 views
Solver cannot find any eigenvalues for linear buckling analysis [COMSOL]
I am trying to do a simple linear buckling analysis, where one end is fixed and the opposing end has a prescribed displacement of -0.1m in the x-direction that compresses the structure. Solver cant ...
1
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1answer
73 views
What Causes Asymmetrical Buckling in this structure?
I've been playing around with structural modelling on the SkyCiv platform and have created this structure, related to a project I am working on to educate myself.
It is 2m wide, 3m long and 1.5m high ...
1
vote
3answers
827 views
Why does the upper wing skin fail in buckling and lower wing skin does not?
I am aware of the fact that the buckling is mainly caused in the regions of the specimen which are in compression. But the wing skin doesn't take any axial loads and is used to resist shear, atleast ...
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44 views
How to calculate how much compression is needed for a spring to buckle
First off; School was many years ago and I know little of the mathematics behind all the physics and engineering stuff. So if you have an answer, please explain it like I'm 5?
The goal: I aim to be ...
1
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0answers
42 views
Interaction of buckling modes
I'm reading this paper on structural members subject to both bending and compression.
In the first paragraph, in context of the equations 6.61 and 6.62, it is said:
The second two terms are modified ...
0
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3answers
64 views
Meaning of this sentence in lecture notes about buckling of nonlinear column
Above picture is from my lecture notes. It deals with a column subject to axial load, which follows Euler buckling theory. The material is nonlinear, approximated by two lines as seen in the stress-...
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0answers
36 views
Program name of this buckling modeling
My instructor sent this solving with program that I don’t know the name , does anyone know the name of the program ?
0
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2answers
68 views
maximum allowed load [closed]
I have the following problem
E= 210 MPa
d = 40 mm
n = 20
y = 1.5
a =1
calculate the maximum allowed load for the system
I am confused on how to solve the problem, I really need advice.
2
votes
1answer
187 views
unbraced length of the compression portion of a long member
I am designing a truss. the bottom chord in the first two panels at each end or at the supports are in compression and the rest of the bottom chord is in tension. there is no lateral bracing along the ...
0
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0answers
93 views
ABAQUS: How to connect a shell edge with a shell face?
I'm performing a buckling analysis of a stiffened aluminium panel. The panel and flatbar stiffener(2) is created as one 3D shell extrusion. The T-stiffener (1) is another 3D shell extrusion.
How do I ...
1
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3answers
214 views
Buckling of Parallel rods
I am trying to calculate critical force $P$, if two rods (same diameter and length - rigid fiberglass sandwiched on two steel plates) are parallel to each other.
$$
P = \frac{\pi^2 EI}{(KL)^2}
$$
I ...
2
votes
2answers
108 views
How do I calculate how many newtons a hollow rod can carry without buckling?
how can I calculate how many newtons a 600[mm] long rod with a known yield strength (300 [MPa]), young modulus (190 [GPa]) and hollow (outer diameter = 16[mm], inner diameter = 10[mm]) will carry ...
4
votes
2answers
88 views
Beam buckling criterion?
If I have an I beam which I subject to some bending load, how can I calculate when the thinner middle part of the I beam will buckle? I though I could use Euler's critical load formula here, but it's ...
3
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0answers
35 views
How do FE solvers solve the case of panel buckling under pure shear?
How do FE solvers solve the case of panel buckling under pure shear?
The main problem is that global matrix of initial stess is singular in that case. One method is to apply some forces that shear is ...
2
votes
2answers
71 views
Using modes from linear buckling analysis as imperfections
I'm reading this article on buckling.
It first introduces us to linear buckling analysis, and then mentions that linear analysis can be unrealistic as it doesn't take imperfections into account. Then ...
4
votes
2answers
110 views
Why is local yielding considered the limiting case in context of buckling in Eurocode?
In Eurocode, when use buckling curves to calculate the maximum load that a compressive member can be subjected to before it risks buckling. Buckling curves are based on the Perry-Robertson formula. I'...
1
vote
3answers
164 views
Why is buckling said to be independent of material strength?
In many sources, such as here, it is said that buckling failure is independent of the material's strength.
But in many building codes, yield stress of the material is a factor that changes the ...
9
votes
8answers
2k views
Definition of buckling as a sudden deformation
On Wikipedia, buckling is defined as follows:
In engineering, buckling is the sudden change in shape of a structural component under load such as the bowing of a column under compression or the ...
2
votes
0answers
33 views
Can the critical buckling load from non-linear FE calculation be higher than the one from linear?
Let's consider a FE buckling calculation without plasticity.
Is there theoretically any chance that the non-linear analysis will give a higher buckling load than the linear one?
2
votes
1answer
156 views
Twist "buckling" critical load
I have a very long beam which is subjected to a torque (I have the moments and shear forces with respect to X along the beam). I can calculate the critical load when the beam would bend if it was ...
1
vote
1answer
119 views
For arc-length method in nastran, how to analyse post-buckling behaviour with load decrease
I am currently trying to model the buckling behaviour of a cylinder using sol 400 nonlinear static analysis using Nastran. I am using the arc-length (modified Riks) method as apparently it can ...
1
vote
1answer
40 views
How would I do a buckling analysis with an additional fixed known lateral force?
I am using Nastran for buckling analysis, and I'm new to all of this so please bear with me.
For a linear buckling analysis, I understand that you must first apply any compressive load in the static ...
0
votes
1answer
76 views
Why is buckling caused by nonlinear geometry?
I've been reading the Comsol post on geometric nonlinearity. The article introduces situations where the small angle approximation and linear analysis of structures gives inaccurate results. For ...
2
votes
2answers
77 views
What is meant by "perfect geometry" in the context of Euler buckling?
In this question for example (in the first answer) it is said that the Euler critical load formula is unrealistic, because it assumes perfect geometry and perfect alignment of the load. I've found ...
2
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3answers
1k views
Buckling vs. Yielding Failure of Columns
As I have been working through examples of construction projects, I've noticed that in nearly every case of a structural column (sample size considers only homogeneous material columns, no composite ...
3
votes
0answers
210 views
Column Buckling Boundary Conditions -- Welded Tubing Practical Application?
I'm trying to do some calculations for a personal project. I'm trying to understand column strength / buckling. My questions relate to Effective Length Constant, which is based on Boundary ...
1
vote
1answer
84 views
Simple steel column buckling calc - where am I going wrong? (Eurocode)
I'm trying to follow an example of this, but I get a wildly different answer than expected and I can't see where I'm going wrong.
The example I've got, is for a 2.8 m steel column (RHS 150 x 100 x ...
0
votes
1answer
268 views
MSC Nastran - BAR3/4 elements - can't assign any properties
I'm modeling a pipe in Patran, and I'd like to try bar3 and bar4 elements.
I assing the properties CBEAM to my geometry, but when I create the mesh, Patran tell me bar3 and bar4 don't support that ...
0
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0answers
44 views
MSC Nastran CQUAD8 on a pipe - excessive pivot ratio
I'm modelling a pipe in Patran with CQUAD8 elements, but I get this error, like the structure is not costrained. I do have costrains on both ends of the pipe. What can the problem be?
If I use ...
1
vote
1answer
122 views
2D Solid - Axisimmetric - Missing properties and material
Goodmorning,
I'm trying to understand how 2D solid elements work. I want to study the local buckling of a simple aluminium pipe with thin walls.
From what I understood, I can use 2D solid elements ...
3
votes
2answers
206 views
How to compute core stress in honeycomb structure?
Assume I have a honecomb(sandwich) panel under distributed normal load. Each edge of this panel is simply supported(pinned) as on the picture below:
The problem is how to find the core stresses σ-z (...
1
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0answers
56 views
Buckling of composite plates help
I am trying to write code for the buckling of composite plates using the Ritz approximation but I can't understand something. According to Reddy (Mechanics of laminated composites), this is the ...
0
votes
2answers
350 views
Hollow Steel Tubing: Critical Load for Sidewall Buckling
I'm looking to construct a something with hollow steel tubing (e.g. 10ga 2"x3" rectangular tubing) suspended horizontally welded to an outer frame on both sides.
I've already calculated the ...
1
vote
2answers
154 views
Can buckling failure at the first critical load be avoided by "instantaneous" loading?
Previously, I was told by someone I trust well that a column can avoid buckling at the first critical load by applying the load "instantaneously" with a magnitude between the first and second critical ...
6
votes
2answers
244 views
Eccentricity for staggered 2x4 wal
I have a staggered 2x4 wall on a 2x6 sill plate as illustrated below (16" on center on each side = 8" on center each stud). The wall is loaded from both sides by floor joists, so I would ...
1
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1answer
1k views
Critical Buckling Load for a Spring Supported Bar
The above is a past exam question from an introductory structural analysis course, one in which although we have studied the Euler buckling load equation, we have just been given parameters for the ...
1
vote
1answer
148 views
Possibility of buckling in non-slender member?
The above diagram is misleading. In reality, both the length and thickness are equal to 8mm. As this is from a past paper (one notorious for awkward questions), I'm not sure if it's a typo (an 8m ...
0
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3answers
2k views
Inertia Relief and Buckling SOL105 in Nastran
Has anyone ever tried running buckling simulations in Nastran where inertia relief is invoked? I am just using a simple plate and I am getting "funny" modes (unrealistically low eigenvalues which ...
3
votes
1answer
271 views
Methods to Measure Buckling without Expensive Equipment
I'm working with some flexures (circularly symmetric tube with pins at the ends). Their bending stiffness matches my FEA. However, I'm concerned that they are buckling, reducing their overall axial ...
1
vote
2answers
526 views
Buckling of a cantilever with midway support
I'm trying to understand the implications for buckling and column sizing in the drawings below.
A 3000mm 120x60 RHS steel column supports a 350mm horizontal steel beam. The column base and right side ...
11
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2answers
4k views
Buckling: Do buckling mode shapes of n > 1 occur in reality?
In the buckling of columns we know that:
$$P = \dfrac{n^2\pi^2EI}{L^2}$$
The smallest value of P occurs when $n=1$ which gives a simple buckling shape (one wave):
$$P_{cr} = \dfrac{\pi^2EI}{L^2}$$
...
