In structural engineering, buckling is the sudden change in shape (deformation) of a structural component under load, such as the bowing of a column under compression or the wrinkling of a plate under shear. If a structure is subjected to a gradually increasing load, when the load reaches a critical level, a member may suddenly change shape and the structure and component is said to have buckled. Euler's critical load and Johnson's parabolic formula are used to determine the buckling stress in slender columns.
Buckling may occur even though the stresses that develop in the structure are well below those needed to cause failure in the material of which the structure is composed. Further loading may cause significant and somewhat unpredictable deformations, possibly leading to complete loss of the member's load-carrying capacity. However, if the deformations that occur after buckling do not cause the complete collapse of that member, the member will continue to support the load that caused it to buckle. If the buckled member is part of a larger assemblage of components such as a building, any load applied to the buckled part of the structure beyond that which caused the member to buckle will be redistributed within the structure. Some aircraft are designed for thin skin panels to continue carrying load even in the buckled state.
Homework Statement
Homework Equations
The Attempt at a Solution
With this problem and in general, I am having difficulties knowing what should be the cubic and what shouldn't be from visual inspection, so in this case I can't tell why I_x is 1/12ba^3, as opposed to 1/12ab^3. How can I tell...
Hello,
I am having trouble understanding why the equivalent length in buckling problems, as well as the moment of inertia, change depending on what plane of buckling you are looking for, and how to calculate the moment of inertia in a particular plane
Alright, I took a while setting this problem up for you guys, because I am absolutely stumped and have hit a brick wall and have nowhere else to turn for assistance. Please excuse the shoddy diagram. I made it from scratch to try to illustrate the problem better.
Homework Statement
Find the...
Hi there,
I was wondering how one can calculate the displacement due to buckling. I already checked the general displacement calculations, but they didn't amount to anything.
So a simply supported beam under compression.
Thanks!
Hi all, I´m a researcher in computational biology thinking on topics quite far from my field.
I want to model long thin-walled tubes of dimensions like those treated here, for example: ≈2 m long, radius ≈50mm and thickness ≈1mm. The tubes I´m interested in should be made of...
Hello All,
I am in the process of creating a 33' tall chaotic pendulum, and cannot find any calculations for the buckling strength of pipe. The pendulum swings from side to side, but is stopped as it goes too far one way or another by a limiting cable attached to a sleeve over the pendulum...
The formulas for buckling under axial force only involve the applied force or pressure, such as with Euler buckling. But if you look at the case of a rocket as the fuel is burned off, the force, i.e., the thrust, stays the same but the acceleration increases as the mass decreases.
But we are...
Hi,
I am carrying out a series of experiments which consist of a square plate object placed over a circular hole. The experiment is done in such a way that I can apply a point force at the center of the plate and see how much force is required to pull the plate through the hole. I should add...
Hello everybody, and a happy new year!
Found in Dubbel (Taschenbuch für den Maschinenbau) page C47 7.3.2 the axial load that buckles a thin cylindre. This is not Euler's buckling of a long compressed beam, but probably from Timoshenko's theory for shell buckling applied to a thin cylinder...
hi, does anyone know how to find how much axial pre-compression is required so that buckling will occur after a temperature rise of 50 C°?
I know the cross section of the pinned at each end copper strip (4mm x 8mm)
length= 100mm
E= 100 GN/m^2
Coefficient of thermal expansion is 18 x 10^-6
Can someone give me a real-life example of an aerospace structure buckling? I need a real example to discuss column buckling theory..etc. I couldn't find any online. Thanks.
Homework Statement
i am struggling with a question i have.. i can't find the right equation to use to find what the minimum length of the column at which buckling is likely to occur??
can anyone offer any help with this as my lesson books show me nothing on how you find length?
i have D=80mm...
I was trying to solve a question where they told me to find the buckling load of a wing strut in a plane that experiences a compressive load along its axis. The strut can be considered to be a pin-jointed at both ends. Dimensions of the strut is as follows: outside diameter is 150 mm and...
https://www.physicsforums.com/attachments/42439
What is the minimum length of the column at which buckling is likely to occur?
The buckling equation is: F= ((∏^2)*E*I)/(K*L)^2
E is the modulus, I is the area moment of inertia, K is the buckling coefficient, and L is the length of...
Hello everybody!
From time to time, I'd like to compute the minimum force that buckles a truss, and hand computations get quickly too complicated.
So: could you recommend me a piece of software for that?
What I need:
- Quickly learned and installed, for Windows, free of nearly (I know...
hi, i am a beginner of this forum.
i am not really sure how to use this forum actually.
i would like to ask, how to find euler buckling load? what is the formula i need to use?
If the cylinder rod is pushing (extending), we have to consider buckling. What happens when it is pulling?
Please let me know what properties of the rod we do have to take care of.
For fixed-fixed BC's, i have to arrest x and y displ. For simply supported case, i have to arrest y displ. Then my doubt is, while applying force at the end of the column, how the displacement will happen for fixed-fixed column.
Hi i am doing my project on corelation between experiment and analysis for buckling. So for doing the experiment i should prepare my own test rig . but how it is possible could anyone help me in my project?
Homework Statement
A rod of leangth L and flexural rigidity EI is pinned at one end by means of torsional spring having a constant beta, and fixed on the other end.
The rod is subjected to a compressive axial force P.
Determine the critical load for instability.(image of the problem is...
in a question i have been asked to assess a steel structure made of two IPE beams given the attached schematic
my question is regarding the buckling of the IPE400, to find the coefficient "K" i have used the julian-lawrence nomogram.
as far as buckling about the Z axis goes, the...
Homework Statement
http://www.imageupload.org/thumb/thumb_62195.jpg
Homework Equations
KQ = PKGQ
where K = stiffness matrix,
Q = displacement vector,
P = buckling load,
KG = geometric stiffness matrix
det(K-PKG)=0
The Attempt at a Solution
Elements 1 (A-B), 2 (B-C) and 3 (vertical) each...
Hi all,
I was looking at the buckling problem of a piece of paper with both ends clamped. When the two ends come closes they form a bulb-like shape and I was interested in deriving the shape numerically by solving NL ODE, which comes from energy methods (neglecting gravity).
The ODE I got...
Hi there,
I'm looking to run an analysis of a thin cylindrical shell using Abaqus CAE. Does anybody know where I can find a tutorial or some fairly beginner friendly material. By the looks of it simula run real life courses on how to use the program but I need to figure a way of knocking...
Hey guys,
Got a quick question here; A simply supported beam of square cross-section is under compression. Which is the preferred direction for buckling? Why? Does your answer change if the beam is clamped at both ends?
a steel rod, 40mm in diameter and 1.00m long, is pinned at each end
i) calculate the euler buckling for the rod
ii) identify three other possible end fixity conditions for the rod and demonstrate how euler buckling load would be affected in each case
iii) explain the relation between the...
Hi guys, I wonder whether we can roughly estimate the energy used to buckle a hollow tube (by calculation)?
I was asked to calculate the backstay of a cane to ensure it can stand for the rebound force due to abnormal operation.
Thanks in advance.
the buckling shape for clamped-free column is v(x)=1-cos(n*pi/2*L), n=1,3,5 ...
how could i use the discrete model to get the buckling mode shape matrix?
for example 3x3 matrix
form a stiffness matrix and solve the eigenvalue problem?
L=1;E=1;I=1
l=L/3 % 3-element beam...
Hi, I am currently studying for my Masters Degree in Mechanical Engineering at the University of Strathclyde (Glasgow, Scotland) and as part of my final project I have to design a 'rig' with which to conduct experiments on climbing belays.
The problem I am having is in designing the 'rig'. I...
Hello,
I have a problem with calculating buckling on a stepped bar with roark's formulas for stress and strain.
By these tables (page 718-722) they show tables where you can find K1 values to calculate the maximum buckling load.
In these tables you compare:
-(E2I2/E1I1) E is youngs...
Dear firends,
I want to study the above siad topic in detail.
Please let me know the exact phenomina or analys steps.
Thanking you in advance,
Regards,
Anil K Vishwa
When calculating buckling force i have only found how to calculate it with a force applied to the entire cross section, how can you use Euler's if the force is applied just to an edge or point.
Thanks
I was wondering if the Euler buckling method is simply theoretical or actually accurate in the real world. I am asking this both for complex structures and a simply compressed rod or beam.
Thanks
Homework Statement
Finding the critical buckling load of a really short column with wide cross section (is it still considered a column?)
E = 22 GPa
Yield: 300 MPa
Load: 28N
thickness: 0.226 mm
I = 670706.51 mm^4 (is this right?)
Load Applied Area (as indicated by white arrows)...
I should probably know the answer to this but anyway...
I want to compute the critical buckling load for a simple 3D rectangular cross-section beam, though the thickness in the z-direction is small.
If a load is applied in the negative y direction, which direction do I use for my...
Hey everyone, so I am in an Adv. Steel Design Course and I am supposed to design a beam under a given distributed DL+LL and Concentrated DL+LL. We are supposed to design the beam under two different conditions... a.) It has continuous lateral support b.) Lateral support is provided at the ends...
Hi,
Thank you for taking the time to look at my problem.
I am considering a vertical pole fixed in the ground at the bottom and experiencing a horizontal point load at the top. This pole is fixed with guy ropes from the top to the ground at a certain angle. See attached image.
Assuming...
Hello
I have a question, I haven't got my books with me.. So hope you can help me..
I have a crane system like this:
http://dl.dropbox.com/u/559096/column.jpg
If the column have the boundary: Fixed-Free. Is there a easy way to calculate the maximum displacement? (in the top)
Knowing that the torsional spring is of constant K and that the rigid bar is of length L, determine the critical load P_{cr} beyond which the column would buckle. See pic for the problem.
[As the spring uncurls, it applies moment K \theta to the bar.]
The answer is P_{cr}=K/L
In Euler's equation is the critical buckling load the force that will initiate a bend in the column, or is it the force that leads to catastophic failure.
If we start with the initial assumption that there is some lateral force due to system imperfections to initiate the buckling. It seems...
Homework Statement
A piece of spaghetti 5 cm in length and 2mm in diameter has a weight of 0.2 gms. It will break under tension at a load of 5 kg (force). And its Euler buckling load is 500 gms (force). What length of the spaghetti could be suspended vertically from one end before it broke...
For an Intro engineering class we've working on a project to make bridges out of spaghetti. To determine if the different spaghetti components of my bridge are strong enough to hold the force that's being applied on them, I've been trying to calculate the spaghetti's critical buckling load for...
Hello everyone,
I am studying for an upcoming exam and have become somewhat confused as to exactly what geometric and material buckling represent. Are they representative of the shape of the neutron flux distribution in the reactor? Are these quantities related to the structural deformation...
Homework Statement
I want to find the euler buckling for a open I beam( middle section like a box) that is subjected to three point bending with a point load on top.
I am not so interest in a solution but explanation on how this could be worked out using the euler equation for buckling...
Homework Statement
the question is in the picture.
the rectangular steel bar shown supports a concentric load of 13000lbf. Both ends are fixed. If te modulus of elasticity is 29x10^6 lbf/in^2, what is the maximum length the rod can be without experiencing buckling failure?
Homework...
I experimented column buckling analysis with different two load conditions in MSC.Nastran.
In the first condition, force was loaded from the downward direction at the top of the column.
In the second case, force was inflicted toward horizontal direction.
But P[critical] of two cases...
Hi,
I have a problem with the experimental buckling load that I have deduced for a compressive axial load applied to a tube of circular cross section. The buckling load is 2.34% larger than the theoretical buckling load! The beam is connected to supports via knife edges; these are rigid bodies...
Hi all,
I am a student of Music technology and for a project that I am working on I need to do an unusual FEA. I want to create a simulated model of the sound phenomenon that occurs when a sheet of material is deformed. As part of this I am required to a dynamic finite element analysis for...
Dear all,
I have a question are as follows:
It is a I-Section joist, the question is find the compressive load could it take with ball-jointed ends.
i want to know what is ball-jointed ends ?? is it mean the base of the I-Section joist ??
if yes, what is the surface area i need to...