Beam Definition and 1000 Threads

  1. 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...
  2. 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...
  3. 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...
  4. 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...
  5. 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
  6. 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...
  7. 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...
  8. 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%...
  9. 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...
  10. 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...
  11. 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...
  12. Saladsamurai

    Short Beam Bending: Roark's Formulas For Stress and Strain

    Is anyone familiar with the Roark's text that can clarify some terms for me? I am trying to clarify what Roark is referring to in the above mentioned text in the section on short beams (in the 5th edition 7.10 and in the 7th edition 8.10). Throughout the text, he uses the terms "span" and...
  13. R

    Calculating Moment of a Beam | PSU Professional Portfolio

    http://www.personal.psu.edu/kar5230/blogs/kyles_professional_portfolio/How%20to%20Design%20a%20Singly%20Reinforced%20Concrete%20Beam.pdf I'm stuck with a formula above. It says that to calculate for Moment of a beam... use the formula Mu= w L^2 / 8 now given w = 1000 lb/ft, L=20...
  14. S

    If a beam of light with an angle of incidence

    Homework Statement The maximum depth of Lake Baikal, in Russia, is 1780.7 m, making it the world’s deepest freshwater lake. If a beam of light with an angle of incidence of 59.42o enters the water from the air, what is the horizontal distance between the point where the light enters the...
  15. T

    A parabolic force distribution is applied to a beam

    Homework Statement The Attempt at a Solution So I noticed the units of w_0 were in N. In other words to find the moment I would have to integrate 100∫01 x2+1-2x dx. However I ended up with the wrong answer. The correct answer requires that I integrate 100∫01 x2+1-2x x dx...
  16. W

    Solving Beam & Magnitude Reactions - 25kg Beam

    Homework Statement As shown, a roller at point A and a pin at point B support a uniform beam that has a mass 25.0 kg . The beam is subjected to the forces f1 = 50.0N and f2= 79.0N . The dimensions are l1= 0.750m and l2= 2.30m . (Figure 2) What are the magnitudes and of the reaction forces...
  17. J

    Finding reaction forces for a Beam

    How do I find reaction for loading condition shown in image. I have no idea how to tackle this type of problem. Please help. http://img6.imageshack.us/img6/725/partilaudl.jpg Uploaded with ImageShack.us
  18. parazit

    Design Beam Line for Free Electron Laser

    Hi friends. Does any of you knows anything about the beam line design tools ? I mean which program could be used to drow an electron beam line of a free electron laser from the gun to the dump ? Each device have to be indicated by name and with some other properties. The diagram must be...
  19. StevieTNZ

    What Happens to Entangled Photons at a Beam Splitter?

    Okay, I have the following scenerio (attached picture). The inputs for path b and c are two photons. both photons aren't entangled with each other - they're entangled to other photons. Before the beam splitter there is a wave plate that converts the photon into the 45/135 basis. So what we...
  20. L

    What are the elements of the strain tensor for a wide beam under bending?

    If I have a wide beam, parallel to the x axis, with its COM at the origin, then I want it to curve about the y axis, what would the elements of the strain tensor be? I have come to the conlusion that the beam would, for example,contract above x-axis and expand below it. But I don't know how...
  21. B

    What Is the Force Threshold for Beam Bending?

    Hi Guys, Do you know of any short formula to calculate bending moment of the beam on the attached image? I need to know the force at which this beam will start bending.
  22. G

    Particle Beam Simulation Service

    Are there any labs or private companies that can run particle beam simulations for a fee? If there are, any suggestions how to find them? thanks..
  23. T

    What's this steel bearing plate going to do under this steel I beam?

    I'm doing some work on my house at the moment, and have had a design produced by a structural engineer for a steel I-beam to span a newly made (4 meter) opening in a brick wall. They've given me a design (see the attached picture for my interpretation) for the bearing of the I-beam which I...
  24. L

    Cantilever beam with non-udl on - solution provided, understanding

    Problem and Solution (albeit to a beam of different length L) provided in attachments. Hi, I have been able to follow the provided solution to get the moment equations and understand the x1 and x2 positional references etc. I also understand that integrating the moment equations provides the...
  25. C

    Deflection in a simply supported beam with a rigid arm underneath

    The attached question shows a simply supported beam with a UDL of 30kN/m and has a rigid arm underneath with a load. This question was a research one but unfortunately I have had no luck. I thought that this could be solved by doing moments for the arm but am unsure on whether that would...
  26. B

    Deflection of electron beam in oscilloscope

    Homework Statement Calculate the deflection of an electron beam as it passes between the plates of a CRT tube. In the picture, the parallel plates create an electric field, with the positive plate on top and the negative plate on bottom, causing the electron's path to be deflected upwards as...
  27. K

    Beam support conditions (Boundary Conditions) in practice

    Hi all. Let's say I want to reproduce the support conditions for a beam. The easiest one I could think of is fixed end. Like I hammer an end of the beam into the wall. This represents fixed boundary condition. Likewise can anyone point out how to reproduce Simply supported end condition in...
  28. W

    Comparing Deck Beams: 4"x10" vs. 4"x12" with Same Material and Load Conditions

    This is for a deck: Which beam is stronger? A) a beam with cross-section dimensions 4"x10" and 8' long B) a beam with cross-section dimensions 4"x12" and 12' long Both beams are same material and are both simply supported at the ends. Same load type (either concentrated or distributed...
  29. S

    Bending moment for curve and straight beam

    It’s clear that bending moment for a curve beam is less than straight one And you can attribute this to moment of inertia, but there is something i don’t understand Which is if i have straight beam with small moment of inertia or huge moment of inertia simple supported beam), the moment will...
  30. Doofy

    What is meant by the term beam spill ?

    what is meant by the term "beam spill"? in the context of a beam of particles from an accelerator?
  31. A

    Sun's light beam and diffraction grating

    Hello. Lets say we have 2 small holes (1&2) which makes tiny light beam from the Sun's light. (similar to laser beam) ......1|......|2... (Sun) -> >-------------------------------------|dg|-----{order 0}-------(Earth) ......1|......|2... |dg| is diffraction grating perpendicular to the light...
  32. S

    Derivation of stiffness matrix for a beam and other related questions

    My main question is why we derive the structure matrix for a beam like the attached first picture; we assume the beam on the left on point B has no deflection? While i check this by computer analsysis program and it has an effect. Please explain in details The second question is the...
  33. C

    How to produce beam of neutrons?

    I am just curious, for nuclear power plant or nuclear weapon/detonation, how to create a beam of neutron that's energetic enough to go inside the U-235 atom and trigger the chain reactions? What was the most conventional or the oldest way to create this beam of neutrons in lab back in the...
  34. O

    Anolok (dark brown) finish to terminate laser beam

    Is it ok to use anodized aluminum with anolok (dark brown) finish to terminate laser beams? Most use black anodized aluminum, but can the former be used instead?
  35. A

    Curved beam stress calculation problem

    Homework Statement Calculate stress in a curved beam and compare with FEA model. Homework Equations Stress = (M*(r-rn))/(Aer) The Attempt at a Solution I used the above formula, which is repeated in many textbooks and reputable engineering websites, to calculate stress in a...
  36. K

    Free Body Diagram for simply supported beam

    Homework Statement As shown in the attachment, a free body diagram (FBD) must be drawn Homework Equations sum of horizontal force = 0 sum of vertical force = 0 The Attempt at a Solution 1. Forces F1 and F2 appear exactly as they are in the FBD 2. At point A, there is an outward horizontal...
  37. P

    A 1 Gev/nucleon ion beam strikes typical matter

    A 1 Gev/nucleon ion beam strikes typical matter ... In this thread: https://www.physicsforums.com/showthread.php?t=622502 the key to figuring out what will happen would seem well modeled by any study or analysis of a 1 Gev/nucleon ion beam striking matter (e.g. a baseball). The density...
  38. J

    Splitting a light beam into opposite circular polarizations?

    Is it possible to split a single light beam into two beams of opposite circular polarization? A properly oriented calcite crystal will separate a unpolarized beam into two beams, one vertically polarized and one horizontally polarized. Other polarizers pass just one polarization and absorb...
  39. S

    Calculate Dead Load of Beam w/ Solid Square Cross Section

    Homework Statement A beam has a solid square cross section of 100mm and is simply supported by two supports 3m apart. Calculate the dead load that can be safely supported when applied to the middle of the beam. Homework Equations Solid square cross section of beam: 100mm Material...
  40. B

    Calculating Moment and Deflection for Handrail Beam with Attached Bolt

    Hello everyone, I have a question regarding the moment and deflection calculation of this handrail beam that I have. I am attaching a picture to give you guys a look at what I am working with. The hand railing is 4" x 4" and it is not attached half way, its just resting on that beam, it...
  41. M

    Smallest diameter collimated laser/optical beam?

    Most of the applications requiring small diameter laser spots are generated by focusing of laser light and that has a theoretical diffraction limited minimum diameter equal to the wavelength. Does anyone know what is the smallest fully collimated beam (small divergence say single digit milli...
  42. D

    Bending of a curved beam to protect a tank nozzle

    In the tank building industry some pressure vessels use curved pieces of flat bar, welded to the tank, to protect nozzles in the event that the tank rolls. I'm trying to determine how thick the flat bar should be for a given length so that it won't bend too much and allow a nozzle to be damaged...
  43. C

    Lasers/lifetime of metastable states on brightness of beam

    If we consider two laser beams with identical 3 level energy level schemes except that the metastable state for one has a lifetime of 1μs and the other, 100μs. Which will give the brighter (more intense) beam? I gather that, since all things are identical up to the metastable state, the...
  44. N

    Dynamic Analysis Cantilever Beam (Staad Pro vs Analysis)

    Hello Phys Forum I’m trying to solve a dynamic problem that involves a cantilever beam fixed onto a support that experiences a time history load on the free end of the beam as shown below: / / /--------------------------------[] / / Cross section Beam is rectangular beam with 1m width and...
  45. J

    Moment Diagram of Cantilever Beam with Fixed End at Left hand side?

    Just want to ask if the moment diagram of Cantilever beam with fixed end at left is the same as with fixed end at right. What I mean is that they are just mirrored ? Thanks
  46. K

    Finding Reactions of Cantilever Beam Inserted Into Wall

    Homework Statement a cantilever beam 5 m long with a mass of 100 N/m carries a concentrated load of 1000 N at its free end. The end of the beam is inserted into a wall 0.5 m thick. What are the reaction on the beam. Homework Equations The Attempt at a Solution My problem is I...
  47. R

    Long Span Beam Design for Optimal Seismic Performance

    Are there any structural engineers here or know the stuff. I'd like to know this. Can structural engineers design long span beam for example 12 meters reinforced concrete beam that is as good as standard 6 meter beam in seismic performance or are 6 meter beams always better compared to 12...
  48. C

    Theoretical particle beam weapon

    This is just for fun so don't take it too seriously... So I've read about particle beam weapons and as far as I understand its simply a concentrated beam of particles ie electrons emitted towards an object. I'm pretty sure I'm missing a big piece here when I say it (it just sound too easy) but...
  49. J

    Calculate the Dead Load on a Simply Supported Beam

    Homework Statement A beam has a solid square cross section of 100mm and is simply supported by two supports 3m apart. Calculate the dead load that can be safely supported when applied to the middle of the beam. Homework Equations Dead Load= volume * weight of material The...
  50. R

    Deflection of a tube beam where hollow is off-center

    So I am trying to figure out how I can calculate the deflection and ultimate bending moment capacity of a hollow tube beam when the hollow portion is not concentric. A regular concentric tube is easy enough but this has me out of my depth. I assume that it will no longer be symetric in its...
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