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.

View More On Wikipedia.org
Recent contents Top users
  1. Nemo1

    MHB Solving Max Distance Between Supports for 2m Beam w/ Yield & Tensile Strengths

    Hi Community, I have this question which I have been able to partially answer. Part 1: From samples, we measured the Flexure Modulus of a material and was asked to solve for the deflection of the material at a $1m$ span and $1kg$ which I used Maximum Deflection = \frac{wl^{3}}{48EI} $W$ $=$...
  2. davidbenari

    The Mystery of the Missing Pi Phase Shift in Gaussian Beam Interference

    The superposition of a gaussian beam and a plane wave generates a pattern of rings whose phase shift before and after the focal plane (of the gaussian beam) is ##\pi##. This means that if you measure interference before and after you'll see the minimums and maximums of intensity invert. We can...
  3. ezgie

    Effect of Collimated lens on Gauss Beam

    Hello everyone, I am trying to find effect of collimated lens on gaussian beam propagation. Do you know how to solve that? I need any equations ,then going to use them via matlab. Thanks
  4. L

    Beam Deflection: Solving with EI w''''(x) = q and Boundary Conditions

    Can the deflection curve of the beam in picture be solved by using the following approach: https://dl.dropboxusercontent.com/u/104865119/beam2.PNG 1) EI w''''(x) = q 2) Integrate four times, solve the constants from boundary conditions (deflection and moment zero at the supports) Thanks...
  5. kiwaho

    I Can electron beam accelerate electron capture beta decay?

    Some nuclides undergo decay of electron capture or beta plus. Can electron beam with appropriate energy accelerate electron capture beta decay? Same scenario: If I am looking for something, and my friend kindly hands it over to me, then I say thanks, because my seeking time is shorten.
  6. chmergatroyd

    Finding weight of a beam using torque & equilibrium?

    Homework Statement A uniform beam at equilibrium is suspended by a cord at X which is 2m from one end of the beam and and 3m from the other end. There is a mass of 28N attached to the 2m end and a mass of 10N on the 3m end. Determine the weight force of the beam Homework Equations...
  7. E

    Undetermined beam problem supported by three different springs

    Hi, I thought it would be an easy one but it isn't... I am trying to solve the problem of a beam supported by three different springs with a uniform distributed load:
  8. B

    Mo Anode X-ray Filtering in Mammography: Why is Mo Ideal?

    In mammography, an Mo anode is used because it produces characteristic X-rays at about 17-20 keV. Apparently, the ideal filter is also Mo. Why is this? Surely all the x-rays would just be re-absorbed by the filter? Thank you
  9. S

    Determine the absolute maximum bending stress of the beam.

    Homework Statement If w = 74 kN/m , determine the absolute maximum bending stress in the beam in MPa. Homework Equations I'm not too sure how to go about my calculations. Please help! The Attempt at a Solution I = [(1/12)*(200*256^3)] - [(1/12)*(192*250^3)] = 29.62*10^6 F = 74*24*1000? [/B]
  10. D

    Solving a Uniform Beam Inclined at an Angle

    Homework Statement A uniform beam of mass m is inclined at an angle θ to the horizontal. Its upper end (point P) produces a 90° bend in a very rough rope tied to a wall, and its lower end rests on a rough floor (see figure below). Let μs represent the coefficient of static friction between...
  11. Vajhe

    Computational Resources for learning about Optical Beam Propagation Method (BPM)

    Hi, I'm a physicist intern that has some problems with Optics simulations; I'm very interested in doing some Beam Propagation Method (BPM) simulation, but the information online is not that good for begginers in the area. Can anyone advise me on books, journals or such that might help me learn...
  12. S

    Does Adding Multiple Point Loads on a Continuous Beam Reduce the Maximum Moment?

    Is the moment in a continuous beam maximum when there is one point load because if you had multiple point loads they would cancel each other out since there are several pin connections along the beam? For example, if I had a 20 kip load moving across a continuous beam and found the maximum...
  13. H

    Does an electron beam bending lose energy by photon emission

    A beam of electron in vacuum with velocity v enter a region of spa e with a electric field E. The field is such the electrons circle with radius r. The electrons are now accelerating at constant tangential speed. Because this is not an atomic orbital then by classical physics the electrons...
  14. Jonski

    Maximum Deflection of Brass Beam: Troubleshooting Homework Solution

    Homework Statement I am trying to find the maximum deflection in a brass beam, however after taking a physical reading the theoretical answer I get is quite off and I am wondering what I am doing wrong. Homework Equations They tell us the max deflection is( Load*Length^3)/(48*E*Second Moment...
  15. R

    A CO2 Laser Beam Folding for 10kw Power Output

    Why is it that equivalent length is so important for laser beam power output (Length = Power/60) - http://www.laserk.com/newsletters/whiteCO.html. I was reading that in order to get multiple kilowatts of power out of a CO2 laser beam you have to fold the beam a great number of times. Why is...
  16. Marcin H

    Why Does the Change in Momentum Equal 2pi in Laser Beam Force Calculations?

    Homework Statement Homework Equations F=(del)p/(del)t The Attempt at a Solution I understand how to do part a, but on part b I don't understand why the change in momentum is 2pi. I originally did the problem by just subbing (del)p with h/lambda. Why is it 2pi?
  17. J

    Calculating stress and strains for beam of applied force

    Homework Statement If I consider a force, which is applied to both ends of a rectangular beam to its cross section with dimensions w (width) and h (height) and I know the length of the beam is l and the force is parallel, how can I calculate the stress? Also, what if the force were parallel to...
  18. Jonski

    Calculating Reaction Force at A for a Beam with Pin Joint | Beam Homework

    Homework Statement Calculate the reaction force at A? Homework Equations ΣMb = 0 The Attempt at a Solution As there is a pin joint at B it is possible to consider the bar only from A-B. From here I applied ΣMb = 0 120 + 20*2 + Ay*4 = 0 This gives Ay = -40kn Also since there are no forces in...
  19. H

    How Accurate Are My Calculations on Alpha Particle Scattering and Energy?

    Hi, I calculated the scattered angle & the kinematic factors for both Al & Au to be Is what I did right? Also E (Alpha) = stopping power x depth = 250 x 0.5 = 125 keV As for the maximum & the minimum scattered energy i didn't know how?
  20. Silverado

    Is My Method for Deflecting a Beam of Electrons Invalid?

    Homework Statement Homework Equations W = -U for conservative forces F = qV x B = qvBsinθ W = Fd for conservative forces K = 1/2mv^2 sinθ = 1 for 90° angles E1 = E2 (conservation of mechanical energy) The Attempt at a Solution [/B] W = -U -Fd = U E1 = E2 K = U K = -Fd = -qvBsinθd K...
  21. R

    Fixed-Fixed Beam with two UDL

    I'm looking for the max bending moment and max deflection of the beam shown in the problem statement. I tried using the double integration method to find the deflection, but it does not look right. I did the model in ANSYS to evaluate the solution, and the result does not match with my...
  22. Alettix

    Measurement of Focal length with Laser beam

    Homework Statement Hi! I have lately come across some tricky experimental physics tasks, where no solution is given. Some of them involved parts where the focal length of a convex lens had to be measured with a laser. How do you do this? Homework Equations 1/l + 1/d = 1/f (1) where f is the...
  23. U

    Structural engineering question -- maximum load taken by beam

    dear all , My question is what is the maximum load taken by beam of UB 610 x 229 x 125Kg/m for a span of 5 mtr? its supported on both side by anchoring on concrete beam.
  24. King_Silver

    Calculating Vertical +Horizontal Forces of Beam in Equilib.

    Homework Statement Below are attached 2 beams, A and B. I have to calculate the vertical and horizontal reactions at both supports in both questions. I have done a lot of calculations and believe I have a good understanding of what is needed to be done however my forces are not balancing for...
  25. S

    Preferential bending loading direction of a beam

    Hi All, I'm trying to think through a problem and was hoping to ping the community for guidance. Suppose you have a beam that's symmetric about 2 axes (like a u channel or a triangular extrusion). Is it better to load the beam in compression on the side with material furthest away or should you...
  26. T

    What happens when an electron is hit by a laser beam?

    Just a quick question. We know that an accelerated electron shoots out light, and light that falls on an electron in an atom, excites it. But what happens to an electron in vaccum, when it encounters a laser beam? If an electron beam from an electron microscope, were to to intercept a laser...
  27. T

    How to reduce vibration of a fixed beam?

    If I want to reduce the vibration of a beam fixed at one end, under a distributed load, does anyone know what this would involve? In the textbook, there is the idea of having a second system consisting of a mass-spring combination to reduce the vibration of the primary system. But I can't find...
  28. B

    Ultrasound - Doppler angle vs. beam steering angle

    In ultrasound what is the difference between beam steering angle and Doppler angle thanks
  29. S

    Beam of Light Exerts a Force, Why?

    According to my optics book when you shine light on an object it exerts a pressure on the object in the direction of propagation. If light is made of alternating electric and magnetic fields, and these fields are in directions transverse to the direction of propagation, then why should the...
  30. M

    Laser Beam Propagation: Calculating Power & Radius

    Hi all, I am interested in finding the power of a laser diode as function of the distance z, assuming a free space propagation. I think to have enough information to work it out but I am stacked at the moment. Given: the initial power, P0 = 1mW beam width clip (e-2 = 13.5%), wx = 3μm, wy =...
  31. ErikaPanda

    Method to calculate beam deflection

    How do you get deflections of a fully restrained beam? :) I already solved for the propped reactions and end moments.. I'm not sure how to do that part. :/ ありがとうございます。 :)
  32. S

    Could a Meson Beam Weapon from Sword of the Stars Ever Be Realistic?

    There's this game called sword of the stars and one of the most interesting weapons is the meson beam. Essentially what happens is that mesons are generated and accelerated close to the speed of light so that they decay once they're inside an enemy ship, thus bypassing all defenses and creating...
  33. L

    Simplification of load on beam for Max M and D

    Guys I have tricky question : I have beam loaded like that: Is there any easy way to do simplification of this load ( I don't mean transfer the UDL to Point Load). Mentioned that I mean the way to not do the calculation of moment to find max in 4 section and the two almost 4 double integrals...
  34. D

    Beam Sizing for Engineering Student Project

    Hi, I'm new here and I'm here to seek for help... I have this school project, I'm supposed to create an app (Funny that they asked an engineering student to do programming huh?). Basically this app involves beam calculations. It's supposed to suggest an appropriate beam sizing ( the cross...
  35. A

    Is P-Polarization Essential for Effective Laser Cutting on Target Surfaces?

    if I have laser beam irradiated normally on the target surface and in the same time time it is p- polarized. under these conditions, we will have the electric field which is completely parallel to the target surface and have a great effect on the target surface. my questions is; is this...
  36. A

    Solving boundary conditions for vibrating beam

    Hi there, I'm solving the equation for the transverse vibrations of a Euler-Bernoulli beam fixed at both ends and subject to axial loading. It's a similar problem to that described by Rao on page 355 of his book "Vibration of Continuous Systems" (Google books link), except the example he uses...
  37. Y

    Reaction forces in a two segment beam

    Homework Statement Homework Equations ∑Fx=0 ∑Fy=0 ∑M=0 The Attempt at a Solution [/B] I am just concerned with part a. I got the correct answers doing this: First, FBD of segment AB: +cw ∑M_A=0: -136 - 6*By = 0 By = -22.7N two ways to get Ay: one: +cw ∑M_B=0: -136 + 6*Ay = 0 Ay =...
  38. R

    Is starlight a TEM00 gaussian beam or plane wave?

    I am simulating a radio telescope and confused on what kind of source should I setup to simulate a star. Should it be a TEM00 gaussian beam or simply a plane wave?Cheers, Robin
  39. sciencejournalist00

    A Quantum entanglement by the means of beam splitters

    I saw many of you saying in their posts that non-linear crystals like barium borate are the only means of producing entangled photons. And because they are expensive, only some of you can afford them. But I browsed the international science magazines and found this...
  40. S

    Patient treatment with photon beam

    Homework Statement Doing some past papers but I got stuck to this question! Any medical physicists can give me a hand please? A patient is treated with a 6MVphoton beam, 12.5 x 12.5cm at 110cm (Source to Axis Distance: SAD) to a 9cm depth. The machine is calibrated to deliver 1.0cGy per MU at...
  41. Z

    Calculating Tension & Mass of AB Beam

    1. Homework Statement I have to calculate the tension of AB beam and the mass. The force of beam BC is 200N 2. Homework Equations My work The Attempt at a Solution T=226.10 M=25.01
  42. M

    Offset Cantilever Beam - Horizontal & Vertical Deflection

    Homework Statement The offset cantilever beam, ABCD, is fabricated from structural steel. Es = 30,000,000 lbs/in2, I = 60 in4. A load of 2000 lbs is placed at point D. Neglect the weight of the beam. Determine the horizontal and vertical deflection at D with respect to A in inches. Homework...
  43. I

    Why Is the Slope of a Beam Zero at Its Midpoint Despite Maximum Deflection?

    Can someone explain why the slope dy/dx = 0 at x = L/2? L/2 is the midpoint and there would be a deflection here so surely the slope of the deflection curve shouldn't be 0? I'm finding it hard to visualise this. EDIT: I think I understand the above. The slope of the deflection curve at x = L/2...
  44. M

    Deflection and slope of a beam, homework question

    I don't get how to solve this problem in the simplest form... I would appreciate your help thanks! I have had some attempts at the question but the question is supposed to be non-calculator-use, so the method should rather be simple, and I couldn't come up with any sort of neat way to solve the...
  45. S

    Tensile Stress at Mid-span of Beam

    Hi, I'm struggling with finding the tensile stress at the mid-span of this beam. I've done the previous questions but have no idea how to begin with this one as I've never dealt with this question before. What is the general method? Correct answer is 1.66MPa. Thanks.
  46. U

    Good source homework problems for beam spring structures?

    Hello there, In this semester I'm studying the vibrations course. In this course we get questions like calculating the total stiffness, set up differential equations and so on. The book that we use (Theory of Vibrations) has not been very useful, our exams give beam spring structures related...
  47. M

    Volume Charge Density of Proton Beam

    Homework Statement 1.0 mA proton beam accelerated through potential difference of 1 keV. Determine the volume charge density of the beam after acceleration assuming uniform current distribution within diameter of 5mm, with zero current outside of this. Particle starting from rest. Final answer...
  48. AdamMcParland

    Integrating Multiple Young's Moduli in Composite Beam Design: Tips and Tricks

    Having trouble figuring out how to link the two Young's Moduli to the Bending Moment, any suggestions?
  49. A

    Who Hits Wall First: Light Beam or Light Traveller?

    I am trying to understand in non-mathematical terms the meaning and physical reality posed by Einstein’s law which tells us that the speed of light is the same relative to all observers. I start with a basic hypothetical: Observer A observes B riding a motorcycle that is traveling at 50 mph...
  50. M

    Light Beam Opposite Motion: Einstein Special Theory

    Hello Everyone. I recently studied the Einstein special theory of relativity. I studied the thought experiment where a beam of light is thrown from a moving spaceship in the direction of its motion and the distance after a certain time interval was different from perspective of a man on...
Back
Top