What is Beam: Definition and 1000 Discussions

An I-beam, also known as H-beam (for universal column, UC), w-beam (for "wide flange"), universal beam (UB), rolled steel joist (RSJ), or double-T (especially in Polish, Bulgarian, Spanish, Italian and German), is a beam with an I or H-shaped cross-section. The horizontal elements of the I are flanges, and the vertical element is the "web". I-beams are usually made of structural steel and are used in construction and civil engineering.
The web resists shear forces, while the flanges resist most of the bending moment experienced by the beam. The Euler–Bernoulli beam equation shows that the I-shaped section is a very efficient form for carrying both bending and shear loads in the plane of the web. On the other hand, the cross-section has a reduced capacity in the transverse direction, and is also inefficient in carrying torsion, for which hollow structural sections are often preferred.

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  1. W

    Modern Physics Question: Davisson and Germer Expt. beam diffraction

    Homework Statement In the experiment of Davisson and Germer (a) show that the second- and third-orderdiffracted beams cannot occur and (b) find the angle at which the first-order diffracted beamwould occur if the accelerating potential were changed from 54 to 60 V. (c) What...
  2. ichabodgrant

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  3. CMATT

    Laser Beam Intensity: Solve W/m², J, & mm | Help Needed

    What is the intensity in W/m² of a laser beam used to burn away cancerous tissue that, when 94.0% absorbed, puts 539 J of energy into a circular spot 2.11 mm in diameter in 4.00 s?? I've tried a couple different equations and I keep getting the answer wrong. This is due tonight, I'm super...
  4. E

    How do I represent load distribution of over hanging object

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  5. Anton Alice

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  6. A

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  7. A

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  8. HorseRidingTic

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  9. A

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  10. S

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  11. B

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  12. C

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  13. A

    What would the angle φ be for this deflected laser beam?

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  14. J

    Question about the location of max bending stress in a beam

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  15. H

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  16. P

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  17. C

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  18. Corwin_S

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  19. Eric Diaz

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  20. David Lewis

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  21. M

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  22. cvnaditya

    How to solve the large deflection of the cantilever beam

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  23. J

    Why doesn't the vertical light beam get out of a black hole?

    For this we need a thought experiment: imagine you're on a gedanken planet manning a gedanken laser cannon, and it's pointing straight up. The light doesn't curve round, or slow down as it ascends, or fall down. It goes straight up. Now let's keep you safe in a bubble of artistic licence, and...
  24. G

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  25. B

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  26. C

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  27. szopaw

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  28. G

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  29. J

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  30. F

    Low-cost low threshold optical beam limiter?

    Do you guys know a low-cost low-threshold optical beam limiter, with cost somewhere ~$100. Or if you know certain method to fabricate such. I would be greatful if you could include links and/or references. I am still noob in photonics so I am only familiar with a beam limiter that blocks the...
  31. S

    Can a beam of light guide or manipulate electrons in motion?

    Can electrons be "guided" or "carried" by a beam of light, something in the manner of how a ship can be guided by a current? So suppose we emit a uniform field of electrons. I don't know if field is the right word. I mean a bunch of electrons of more or less uniform distribution are being...
  32. C

    How to find beam spring stiffness coefficient?

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  33. J

    Derive Euler–Bernoulli equation from Navier-Cauchy equations

    Hello Is it possible to derive the Euler–Bernoulli equation: \frac{d^2}{dx^2} \left(EI \frac{d^2w}{dx^2} \right) = q from Navier-Cauchy equations: \left( \lambda + \mu \right)\nabla\left(\nabla \cdot \textbf{u} \right) + \mu \nabla^2\textbf{u} + \textbf{F} = 0 I don't really know where to...
  34. A

    Beam Deflection with single support

    Hello I am trying to setup a problem to represent a pipeline crossing over another perpendicular pipeline on the seabed. I am trying to represent the problem as a simple beam and having some issues with the supports i am selecting and the boundary conditions. Attached is a picture representing...
  35. Turbine

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    Hi guys, Hopefully a fairly simple question. All beam formulas I've come across, whether in my own textbooks or Machinery's Handbook, have two sets of formulas for beams. One will be for "simply supported", where one end is pinned and the other end is a pin-roller. The other connection type is...
  36. acron

    Making a Particle Beam Cutter: Physics Perspective

    How would one go about making a particle beam cutter? I'm thinking like a powerful laser type cutter. Please no mechanical engineers, I want a purely physics point of view.
  37. acron

    A Phased directed energy beam emission

    How would someone go about to make a phased particle energy beam? What are the physics behind it? Any research that anyone knows on the subject that I could take a look at? Thanks
  38. A

    MATLAB How to calculate stress on a beam using MATLAB?

    Hey all, I want to calculate the stress and strain on a beam using MATLAB and I would also like to make a stress-strain curve as well. The problem is as follows: I have a hollow rectangular aluminum beam that is fixed at both ends. I have the material properties and the dimensions of the beam...
  39. M

    Load on a beam: More unknowns than equations?

    Homework Statement Homework Equations FBD and all forces and moments = 0 The Attempt at a Solution Sketched in the image. So, I don't know how to go on with my analysis of the load, since I can't determine the reaction forces. Can someone please help me? Thanks in advance!
  40. M

    Beam statics: continous load analysis

    Homework Statement I just don't understand how to set the problem for the free body diagram (point (a) and (b)). Can someone help me with this problem? Thank you in advance.
  41. K

    How to estimate the power of laser beam

    I posted a question about Rabi frequency here https://www.physicsforums.com/threads/what-is-rabi-frequency.331082/ some times ago. The replies there answer some of my questions but I am still looking for detail explanation on the relation between Rabi frequency and the power of the beam. I read...
  42. Daumantas

    Bending moment of countinuous tapered beam

    Hello, I can't find the formula for bending moment calculation of continuous tapered beam. the cross section is I (H) form, where web is 179.5 cm flange is 67 cm, web thickness is 1.5 cm and flange thickness is 2.5 cm. And this beam changes its height to 89.7 cm all other dimensions is the...
  43. I

    Find the frequency of the oscillation of a horizontal beam.

    Homework Statement A uniform meter stick of mass M is pivoted on a hinge at one end and held horizontal by a spring with spring constant k attached at the other end. If the stick oscillates up and down slightly, what is its frequency? [Hint: Write a torque equation about the hinge.] The length...
  44. C

    Virtual work in finite plane bending of Euler-Bernoulli beam

    Please refer to the following image, which shows a portion of the deformed centerline of a beam in its equilibrium configuration with a uniformly distributed load. The stress resultants are the axial forces T, transverse shears Q, and bending moments M at sections 1 and 2, with the rotations...
  45. cvnaditya

    Deflection of cantilever beam having two Young's modulas

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  46. J-dizzal

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    Homework Statement Homework Equations ΣF=0 ΣM=0 The Attempt at a Solution I think i correctly identified two 2 force members at A and B. But would the system be a 3 force member? If it is i don't quite know how to solve for the missing angles. Is the problem asking for the sum of the...
  47. J

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  48. B

    Particle beam has What Amount of voltage per meter LHC

    So for sake of example the LHC beam one pointing at the other to cause a collision, the one beam is 6.5 TeV per beam. How can I calculate the volts per meter or given size of pulse? I understand that the particles have kinetic energy in the form of the speed of their travel but theoretically...
  49. B

    Could a particle beam reach the surface of the moon?

    Could a particle(proton, gold ion, electron) beam reach the surface of the moon, given current technology? Would the beam diffuse too much too scenter the regolith? Or would the beam have to be focused or continually refocused in order to achieve that? If so why can they do it with laser...
  50. M

    Forces and Friction on a Block and a Beam

    Homework Statement A block of mass M = 1 kg is placed between a vertical wall and the end of A beam mass m = 10 kg . If μ S = 0.6 A , determine the minimum value of the angle θ min θ for which the block remains in equilibrium and the coefficient of friction Static B μ S corresponding to prevent...
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