Beam Definition and 1000 Threads

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. M

    Bending a Beam to Produce Uniform Tension

    Hello. I am attempting to build a fixture which will place uniform tension onto one surface of a rectangular beam. I know that I must force the beam to deflect along a set path, but I am having trouble determining what the equation for this path needs to be. Any guidance on this would be...
  2. H

    Polarization of white light beam

    I want to find out that what happens if we polarize a white light which has all of the wavelenghts of 400-700 (nm).Does it divide into colors?What happens to it?
  3. B

    Natural Vibration of Beam - Algebraic Query

    Folks, Just wondering what the author is doing here, given ##\displaystyle \left (\frac{2EI}{L^3} \begin {bmatrix} 6&3L\\3L&2L^2 \end {bmatrix} -\omega^2 \frac{\rho A L}{420} \begin {bmatrix} 156&22L\\22L&4L^2 \end{bmatrix} \begin {bmatrix} W\\ \theta \end {bmatrix} \right )=\begin...
  4. B

    Finding Net Torque on a Beam: Calculating Torque about Different Axes

    Homework Statement Calculate the net torque (magnitude and direction) on the beam in the figure below about the following axes. (a) an axis through O, perpendicular to the page (b) an axis through C, perpendicular to the page Homework Equations The Attempt at a Solution I...
  5. B

    Where Did the Exponentials Go in Beam Vibration Analysis?

    I am just wondering the author is doing in this calculation step. Given ##\displaystyle \rho A \frac {\partial^2 w}{\partial x^2} - \rho I \frac{\partial^4 w}{\partial t^2 \partial x^2} +\frac {\partial^2 }{\partial x^2}EI \frac {\partial^2 w}{\partial x^2}=q(x,t)## where ##w(x,t)=W(x)e^{-i...
  6. C

    Pion production with an electron beam

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  7. B

    Statically indeterminate beam (fixed ends) and the moments at the supports

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  8. S

    Length & Bending Stress: How Does Beam Length Impact Stresses?

    if you have a beam or something, anchored at one end and apply a moment at the other end, then the bending stress is given by M*y / I, where I is the moment of inertia of the beam. what affect does the length of the beam (i.e. the distance between the anchor and the end of the beam, where the...
  9. B

    Exploring Beam Deflection: Area Moment, Moment of Inertia & Center of Gravity

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  10. B

    Kinematics of Euler Bernoulli and Timoshenko Beam Elements

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  11. S

    I Beam Trolley Bearing Type

    I am having trouble finding the difference between and I beam Trolley with a roller bearing and a sleeve bearing? I know that the roller bearing has 4 wheels that sit on the bottom base of the I Beam and roll back and forth but I am not sure how a sleeve bearing is different from that? Thanks
  12. N

    Find the Shear and Moment on the Beam

    Homework Statement Derive expressions for the shear force V and bending moment M as functions of x in the cantilever beam loaded as shown. Then answer the questions. At x = 2 ft, V = M = At x = 9.3 ft V = M = I have attached an image of the question The maximum...
  13. Telemachus

    Stern-Gerlach, polarized atom beam.

    Homework Statement In a Stern-Gerlach device, an atom beam with angular impulse J, travels through a magnetic field applied normally to the trajectory. The beam is separated in 2j+1 beams in general. Find the relative intensities for these beams if J=1 and if the beam is polarized with jθ=1 in...
  14. C

    How to work out the mean shear stress I section beam

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  15. M

    Moment of Inertia of a hollow beam inside a rubber shell

    Hello guys, I am calculating Bending and Shear stresses in hollow beams. We have a particular kind of shell that we use for impact loading, so we put rubber discs around the steel shell. So my question is, how will it affect the moment of inertia ? Since I know that the rubber discs will...
  16. M

    Calculation of Bending Moments and beam deflection

    Homework Statement The picture of the beam below has a module of rigidity EI, determine the reactions at the supports and the equation of the deflection curve of the left half of the beam Homework Equations v*EI=((Ma*x2)/2)+((Ra*x3)/6) Ʃ of Forces in Y direction = Ra+Rb=0 Ʃ Moments...
  17. R

    Hinged beam suspended at an angle

    Homework Statement A 35.8 kg beam is attached to a wall with a hinge and its far end is supported by a cable. The angle between the beam and the cable is 90°. If the beam is inclined at an angle of theta=17.8° with respect to horizontal, what is the horizontal component of the force exerted by...
  18. S

    Fixed Ended Beam applied to couple moment

    Homework Statement Hi, i am trying to understand how to find the reactions (Ra & Rb) and moments (Ma & Mb) of the beam shown in the sketch below. Not an exact number but in terms of Mo(couple moment) and L(length). Homework EquationsI have the answers which are Ra = -Rb = 3Mo /2L AND Ma...
  19. M

    Multi-Section Beam Bending Calculations

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  20. B

    Stress on a beam supported by mass-less cable, friction at play, no angle given

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  21. Z

    Find Time t_0 for a Beam to Not Catch Up with Earth

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  22. B

    Moments of deflection/ curvature of radius of a supported beam

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  23. B

    Euler Bernoulli Beam 4th order ODE -Balance of Units

    Folks, I am trying to understand the balance of units for this eqn ## \displaystyle \frac{d^2}{dx^2}(E(x)I(x) \frac{d^2 w(x)}{dx^2})+c_f(x)w(x)=q(x)## where ##E## is the modulus of Elasticity, ##I## is the second moment of area, ##c_f## is the elastic foundation modulus, ##w## is...
  24. T

    Statics: Balancing beam of unknown length

    Homework Statement A horizontal meter stick has a mass of 217 g. Three weights ride on the meter stick: 265 g at 40.7 cm, 191 g at 75.9 cm, and 195 g at 99.3 cm. At what location on the meter stick would the system be in balance if it were suspended there?Homework Equations ƩF=0 Ʃτ=0 Center...
  25. 1

    High energy proton beam collimation

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  26. S

    Why we have to tap the frame during Deflection of Beam Experiment?

    hi, last week we did an experiment to find the deflection of simply supported beams. During the experiment, after every measurement we had to tap the frame slightly. Does anyone know why we had to do this? If you could explain it to me I would be grateful.
  27. D

    MHB Vibrating beam concept question

    If we had a beam fixed at $x = 0$ and on pin rollers at $x = L$, why would $u_{xx}(L,t) = 0$ and $u_x(0,t) = 0$. $u(0,t) =0$ since the at $x = 0$ the beam is fixed and $u(L,t) = 0$ since the beam is on roller and wouldn't have any displacement, correct?
  28. M

    Kinetic Energy of Electron Beam.

    Homework Statement Two horizontal plates connected to 600v with the positive at the top. A positively charged ion between the plates moves downwards under the force of the field (neglect gravity). The ion has charge 1.6×10^–19C and mass 2.3×10^–26kg. Show that the kinetic energy of the ion is...
  29. C

    Bending moment of I section beam

    Homework Statement Hi everyone this is my first post. I am having a problem with the bending moments of the beam (see attached files). I cannot for the life of me seem to get the bending moment to finish at 0 so I can draw the bending moment diagram. I know this is generally quite a simple...
  30. C

    Calculating the mass of a beam of non uniform density.

    Been doing some physics problems from my mechanics class. This is the first time I've attempted a problem like this and am not so confident with solving it, I could be correct and just being paranoid but I just have a feeling I've made a mistake somewhere, would appreciate if someone who is...
  31. M

    Obtaining the Green Function for Euler Beam with Specific Boundary Conditions

    Hello there, I would like to obtain the Green function for the operator F, F [u(x)] = u '''', and the boundary conditions u(0) = u'(0) = u (1) = u' (1) = 0. I am looking for a function G ( x, s ) such that G'''' (x,s) = delta (x-s) (the apecis referring to differentiation w.r.t. x, and...
  32. S

    Cantilever Beam Failure as a function of Force Applied to Free End

    Hello, First post, go easy. Trying to do some basic calculations on how to find when a steel cantilever beam will yield when a load is applied to the free end of the beam. I have attached my best MS Paint diagram of the problem. Assume the left end is clamped and essentially a fixed end...
  33. D

    A cantilever beam, find the tension forces

    Homework Statement http://i.imgur.com/5p9UF.jpg The Attempt at a Solution http://i.imgur.com/LZtRh.jpg and this is what was tried to do. But apparently T2 is complete off, any ideas? Or there is some other way to calculate this? Or perhaps someone can point me to better book other than...
  34. P

    Why is the second cross section preferred for designing a beam?

    Consider the cross section of two beams of same material as shown in the file attached. The area moment of inertia I about the central axis is equal for both the c/s. I have calculated it. Can somebody explain why the second c/s (2 in the figure ) is preferred for the design?
  35. R

    Maths solution for partially restrained cantilever beam

    Hello Can somebody guide me to a mathematical solution for a cantilver beam which is totally restrained on only 2/3 of its depth. Thanks in advance
  36. Telemachus

    Particle beam without spin into a magnetic field

    Hi there. I have to solve this problem. The statement says as follows: A particle beam with l=1, without spin and with momentum p is incident on the plane x= 0. In the region x<0 the particles move freely and for x>0 are under the action of a constant magnetic field H in the z direction V(x) =...
  37. H

    Beam overhang pressure distribution

    Hi, Please do not shout at me if you find this query posted on another thread; I am spreading my net wide. I am investigating the overhang beam pressure distribution when part of the beam is resting on an elastic foundation. We are all aware of the assumption that when a moment is reacted...
  38. karush

    MHB Max Beam Deflection: Find $x$ Value for $D$

    The deflection D of a beam of length L is $D=2x^4-5Lx^3+3L^2 x^2$ where $x$ is the distance from on end of the beam. Find the value of $x$ that yields the maximum deflection. this is from a unit on inflection points so assume this is $\frac{d^2}{dx^2}$ and also looks like an implicit...
  39. L

    Torque of man on a beam trying to paint his house

    A man of mass mm = 95 kg decides to paint his house. To do this, he builds a platform using a uniform beam with a mass of mb = 100 kg and a length of L = 7 meters. The beam is supported by two sawhorses, as shown in the diagram above. 1) If the man stands over the support at point B...
  40. H

    Find height of ball under water beam

    Homework Statement The 250 g ball is supported by the vertical beam of fresh water which issues from the 12 mm diameter nozzle with a velocity of 10 m/s. Calculate the height h of the ball above the nozzle. Assume the stream remains intact and there is no energy lost in the jet stream...
  41. L

    Tension in the hawsers holding a beam

    Homework Statement In the illustration we have a beam attached to 2 hawsers which are BX and DY respectively. We have pressure mounted on different parts of the beam. What is the tension in the hawsers Homework Equations The Attempt at a Solution I don't know how to approach this...
  42. E

    Moment of a Distributed Load on Beam, Scanned work and Diagram.

    Homework Statement Determine the forces of reaction.Homework Equations SUM of Y forces=0 SUM OF FORCES ABOUT POINT B = 0 The Attempt at a Solution My attempt is in the link, I scanned the diagram along with my work. Thanks for the feedback, appreciated. http://imgur.com/i3cB2 <----- Link
  43. A

    Vibrating uprigt cantilever beam

    Suppose a cantilever beam stands uprigt, such as a tube attached to the floor in one end and free at the other end. Suppose then that a force is applied normal to the beam at some point along the beam causing a deflection. Then suppose that at t=0 the force disappears, and the intertia of the...
  44. A

    How to calculate radius of curvature of beam?

    If I start out with a flat beam of length a and then I fix one side and then bend the other side up to form an arc with height h, is that enough information to determine the radius of curvature of the bent beam? If so, how would I do it? Thanks...
  45. V

    Minimum beam dimension for specific max stress

    Homework Statement A beam (note: part of a truss, I chose to use the beam in the truss with the most force and length for my calculations, which I assume is the correct thing to do) of length 6m with a force of 9N is being constructed out of a material with a Young's Modulus of E = 70 \times...
  46. T

    Beam splitters cubes configurations

    Hello guys, I'm not sure this is the right place to ask the question, but I hope someone would have experience with beam splitters cubes. If I want to split a laser beam over more than one level with more than one beam splitter cube, so the first beam splitter splits to two beams with 50%...
  47. E

    Tapered cantilever beam deflection and stress distribution

    Homework Statement A positive moment of 12000Nmm at the tip applied as two equal and opposite point loads of 1000N in the x direction at C and D. The beam is fully fixed along AB. Young's modulus E = 200*(10^3) MPa and the poisson's ratio = 0.3. Geometric Properties: Width, b=10mm...
  48. D

    What is the required force to achieve constant radius beam bending?

    Hi All, I need to calculate how much force is required to bend a beam to a constant radius. The beam will be simply supported on both ends and the force will be applied much like a 3 point bend but with a curved face instead of a single point. For most of my application, the beams are...
  49. J

    Gaussian Beam Width and Refractive Index

    Homework Statement I know that in free space, the width of a Gaussian beam can be written as W=W_0\sqrt{1+(\frac{z}{z_0})^{2}}. However, I was wondering if it was possible to express this width as a function of refractive index instead (since I don't believe a Gaussian beam originating in say...
  50. R

    Axial traction of a beam on support

    hello My question is rather off the usual queries concerning beams, which is maybe why I'm struggling to find a solution. If we suspend a totally rigid beam at its extremities with springs to measure forces, the springs will both indicate q x L /2. If the beam is supple, it will sag and...
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