# Questions tagged [structural-beam]

A structural element whose length greatly exceeds both its width and height, which are of the same order of magnitude.

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### Is the shear stiffness of a helical spring for bending negligible?

I want to model a helical spring by beam theory. Lets call $d$ the stock wire diameter and $D=2r$ the the helix radius (see picture below). For example: The axial stretch stiffness is given as here. ...
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### Why does a cantilever beam bend instead of shearing when a point load is applied?

I have just learnt about cantilever beams and that they are free on one end and supported on the other. In my class, my teacher showed an example of when we apply a point load at the end of a ...
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### Beam splitter using a lazer to do the splitting

My title may be misleading, and my question is definatly amateur. I would like to split a beam of light, with a second beam. I suspect this may not be possible (or only possible with large amounts of ...
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### Transfer and distribution of forces in hybrid structure

It's a simple but curious question. For an object made of reinforced concrete, it is said that concrete mainly resists compression force and reinforcement mainly resists tensile force. Whether it's ...
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### Calculate bending moment for cantilever with uniformly distributed load

I am trying to understand how to calculate the bending moment for a cantilever with a uniformly distributed load so that I can build an equation of moments, as shown in this example: I tried ...
325 views

### Moment of inertia of a cantilever beam [closed]

As part of a project, I'm calculating deflection of a cantilever beam, something like the image below where the beam bends due to a load. To do so requires its moment of inertia, and I'm thinking of ...
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### Why does the beam splitter create superposition?

Why does the beam splitter create superposition ? Ok, in a double slit you have 2 holes in a wall, and thus there are 2 ways through which the particle to go. But in a beam splitter where are those 2 ...
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### Elasticity and Hooke's law: who is applying the force?

I am currently studying longitudinal vibrations in an elastic beam. However, I am struggling a bit because it is the first time I have done continuum mechanics. More specifically, when isolating an ...
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### Derivation of equation for period of cantilever beam when the distance between the point at which a mass is attached and the pivot changes

I am a high school student writing a research paper on cantilever beams. I am investigating the relationship between the distance at which a fixed mass is placed on the beam and the time period of its ...
440 views

### 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 ...
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### 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 ...
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### Huygens-Fresnel integral and Rayleigh integral

While working with the Huygens-Fresnel integral, I learned about the Rayleigh integral again, and I can't tell where they apply and whether they can be replaced equivalently. Also, in terms of ...
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### About EBW (Electron Beam Welding) [closed]

I'm an electron beam welding process engineer. We use vacuum chambers to produce close tolerance welds for the aerospace industry. The vacuum chambers are pulled down by cryogenic pumps on the newest ...
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### FFT plot not aligning with lower natural frequencies

I have a cantilever beam with gapped springs on top and bottom and an impulse is given at the free end initially. I modelled it using finite element method with 30 elements. The beam then oscillates ...
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### Is Euler–Bernoulli beam theory still correct for non-constant (but continuous) beam cross-section?

How can I use Euler–Bernoulli beam theory for non-constant beam cross-section ? The beam is modeled as a continuous cone of known inner and outer diameters (both a function of $x$ the distance from ...
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### Strength Calculation of a Simply Supported 3D rectangular beam Under Loading As Shown In Image Attached

For a 2D and 3D circular beam we can easily calculate the strength of beam and reactions using beam theory. The same can be used for 2D rectangular plate. Also for a 3D rectangular plate with uniform ...
1 vote
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### How to find Shear Force and Bending Moment in Finite Element Method for a cantilever beam with many elements

I have a cantilever beam with lots of elements. I am trying to find the sheer force and bending moment diagrams of the beam. EVERY SINGLE TUTORIAL AND EXAMPLE I SAW ONLINE SHOWS HOW TO DO IT FOR A ...
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### Transverse Vibrations of a Cantilever beam. Why does the % change in nth natural frequency increases with n in this case?

This is the problem in detail I have a cantilever beam. Now I am making it stand upright and adding water for different heights of SUBMERGENCE I am doing this by adding an ADDED MASS term from the ...
1 vote
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### Why is the strain independent of the type of material (in beam bending)?

When a beam is bended, the strain that is produced above and below the neutral axis is proportional to the curvature of the beam and varies linearly with the distance from the neutral axis. But why is ...
862 views

### Deriving an equation for the SHM of a cantilever beam with a mass attached at the free end

I'm a high school student doing a research paper on the vibration of cantilever beams. Specifically, I am investigating the relationship between the mass on a cantilever beam and the time period of ...
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### If the range of a laser depends on its crossection perimeter does it mean that a wider beam would reach much longer distances?

If the range of a laser depends on its crossection perimeter does it mean that a wider beam would reach much longer distances? Let pressume that we can construct a 1m wide laser beam and as we know ...
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### Doubt in derivation of bending of beam, It's about derivatives and intergration

Radius of curvature of the beam in above picture is given as: $$\frac{1}{R} = \frac{d^2 y}{dx^2}$$ Please help me two points used as steps of a derivation in my book: How was the radius of ...
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### Why two wires are used in railway overhead equipment? [closed]

While watching the train video's I came across this overhead wires. After searching on internet I found that both catenary and contact wires carry same voltage and connected by vertical wires called ...
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When a load P is applied gradually on an object, the work done on it is the average of the initial and final loads, which is generally P/2 multiplied by the deflection Δ1. In the case of impact load, ...
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### Inconsistent units in modal analysis of vibrating beam

(read the last sentence for the actual question). Consider an elastically suspended solid body from a massless cantilever beam The equations of motion of such a system are \begin{bmatrix}m\\ & ...
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### Do inertia affect stiffness matrix of beam?

Refering to a pdf I uploaded at here. Why does these stiffness matrix displacement do not need to consider the inertia (determines the shape of cross-sectional area of each element) ? I have always ...
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### 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 ...
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### The state of a Stress element isolated from a beam

Consider a beam subjected to an arbitrary loading, where the loads are only present in the plane of bending. The x-y plane is the plane of bending. If I take a stress element in the beam, there will ...
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### Twisting Solid Steel Bar - Annealed, Hardened or Doesn't mater? [closed]

Workshop project underway... Been decades since I was in a physics class. Building something out of steel - options are mild steel 1018 and alloy steel 4140 that can be hardened by heat treatment. ...
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