Questions tagged [buckling]

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3
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2answers
147 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 (...
6
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2answers
217 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 ...
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3answers
43 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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3answers
628 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 ...
2
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1answer
91 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 ...
0
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1answer
193 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 ...
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0answers
40 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
36 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 ...
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0answers
34 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 ?
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2answers
60 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
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1answer
61 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
30 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 ...
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3answers
98 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
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2answers
79 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 ...
3
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2answers
71 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
34 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
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2answers
60 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
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2answers
71 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'...
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8answers
1k 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 ...
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2answers
79 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 ...
2
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0answers
30 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?
1
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1answer
55 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
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1answer
37 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
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1answer
51 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
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2answers
58 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 ...
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3answers
690 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 ...
2
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0answers
82 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
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1answer
65 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 ...
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0answers
29 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 ...
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 ...
1
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1answer
80 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 ...
1
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0answers
52 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
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2answers
227 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
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2answers
137 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 ...
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 ...
3
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1answer
238 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
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1answer
138 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 ...
1
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2answers
493 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): $$P_{cr} = \dfrac{\pi^2EI}{L^2}$$ ...
3
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1answer
363 views

How thick does an aluminium vacuum cylinder have to be?

Take a hollow aluminium cylinder with outer radius $r$ and length $h$, capped with two circular endcaps. How thick does the aluminium have to be, that is what is the inner diameter of the cylinder, ...