A structural element whose length greatly exceeds both its width and height, which are of the same order of magnitude.
Questions tagged [structural-beam]
160 questions
18
votes
1 answer
Why is paper inelastic but flexible?
Recently I have been studying solid structural mechanics, and one of the points I find really confusing is how elasticity and flexibility are closely intertwined.
Consider an Euler-Bernoulli beam, for instance. The flexural rigidity of the beam is…
FLP
- 327
16
votes
3 answers
Similarity between Schrodinger and Euler-Bernoulli equations - any possible physical meaning?
I noticed a long time ago the similarity between Schrodinger equation and Euler-Bernoulli beam equation. Namely, Euler-Bernoulli equation is equivalent to the system of Schrodinger equation for a free particle and its complex…
Yuriy S
- 595
16
votes
6 answers
Why does diamond have lower tensile strength than Iron?
Let me first give you the tensile strength of both substances:
Diamond: 1600 MPa
Steel : 2617 MPa
As you guys should know, tensile strength is how much a material can be stressed or pulled before it breaks. The data above shows that diamond is…
Vaishnavi
- 1,107
11
votes
6 answers
What is the role of pillars in bridges?
As I can see in the picture, there are so many pillars which are holding the bridge. This picture gave a question to me that what are these pillars doing below the bridge?? An appripriate answer could be "these are providing support to bridge".
I…
Vidyanshu Mishra
- 1,859
- 3
- 22
- 42
9
votes
3 answers
Tower of building blocks
Why does a tower of building blocks (cubes) fall?
Theoretically, as long as the center-of-mass is above the blocks' bottom faces, and as long as one does not shake the tower too much, it should not fall. This means that, with sufficient care, one…
Roger V.
- 68,984
5
votes
1 answer
Solving the differential equation of a beam under moving load using green functions
i started working on this paper and i didnt understand one part of it , the problem is :
Solve this equation using green functions :
$$ EI {\partial^4 y(x,t)\over\partial x^4}+\mu {\partial^2y(x,t)\over\partial t^2}= F(x,t) :(1)$$
$$F(x,t)=…
Lofaif
- 53
- 5
4
votes
3 answers
What do tensile strength values mean and why are they reported in units of pressure?
How does one interpret the numbers when reading data about tensile strength, yield strength, and the likes?
Say for example reinforcing bars. Grade 40 Rebars are rated at 70,000 PSI for its ultimate tensile strength and 40,000 PSI for its yield…
user33483
- 41
4
votes
1 answer
Computing the strain in a cantilever beam under a known deflection
I intend to use a cantilever beam to calibrate a strain gauge, in a setup similar to the picture.
My idea is to introduce a small known vertical displacement $\delta$ on one side of the cantilever through a micrometric screw and to compute the…
user386164
- 123
4
votes
2 answers
Stress in a thick-walled pressure vessel
I can find many references that give the stress in the walls of a pressure vessel for spheres and tubes, but they all seem to be limited to a thin-wall approximation. I'll limit my writing here to spherical vessels (I don't think it should be very…
Alan Rominger
- 21,318
4
votes
1 answer
An intuitive reason for the fourth derivative in the beam equation?
The appearance of the second derivative (or Laplacian in higher dimensions) in the diffusion equation ($u_t=u_{xx}$) and the wave equation ($u_{tt}=u_{xx}$) seems intuitive to me. The quantity simply represents deviation from the local average - and…
FusRoDah
- 1,219
4
votes
0 answers
Explain cantilever dynamics of first mode
I would like to implement the time-dynamics of the first mode of a homogeneous cantilever, $w_1(x, t)$. I have found the equation for the first mode in…
Aleksejs Fomins
- 211
3
votes
1 answer
Large deflection of cantilever beam
How can I find the amount of point force at the end of a cantilever plastic beam that produces e.g. 45° slope at the end of the beam? Is this the right equation: $$F=\frac{2EI\theta ^2}{L^2 \sin(\theta)}$$
I derived this equation by putting…
NESHOM
- 131
- 2
3
votes
1 answer
Why are there no vertical normal compressive stresses when a horizontal beam has a vertically applied load?
In a beam with a a single vertically applied load and a single vertical reaction force, as well as a reaction moment, for example, this one:
We would typically consider the normal stress ($\tau_{xx}(x,y)=\frac{Fxy}{I}$, where $I$ is moment of…
Ian
- 147
3
votes
1 answer
Why is beam forming more energy efficient than a straight up omnidirectional signal?
Someone tried to explain the process of beam forming to me, and how beam forming is far more efficient than an omnidirectional signal of similar amplitude.
This seemed obvious at the time: the power of the signal is proportional to the integral over…
securityN00b
- 33
3
votes
2 answers
Why are truss members two force members and why are the forces directed along the axis of the member?
In Hibbeler's book, Engineering Mechanics: Statics, on pages 264-265 it is mentioned that two assumptions are made in the design of a truss:
All loadings are applied at the joints
The members are joined together by smooth pins
Hibbeler goes on…
Data
- 131