Beam Definition and 1000 Threads

  1. F

    Calculating Reaction Forces in a Beam - Moment About Point B

    I am calculating the all reaction forces in this beam. However, I want to ask: By taking moment about point B, why does the moment of the UDL become 15*7*5.5 instead of 15*7*4.5 Thanks !
  2. DrVirz

    Solving Beam with 2 Hinges: Struggling with FBD & Forces

    Hi all, Having trouble with the following question, trying to work out the FBD and forces. I am fine with working out the max tensile and compressive forces however I can't get that far as the two hinges are throwing me off. As I understand, the moment at the hinges should be 0, is this...
  3. R

    Bridge Beam Shapes: Why Are They Different?

    I pass a river with two bridges on it, right next to each other. One older, one newer. The newer one is all concrete construction & the shape of its spans makes intuitive sense to me i.e. minimum thickness at mid span. Like this sketch: The older one has sort of the opposite shape with max...
  4. J

    What Is the Minimum Beam Energy for Proton-Proton Collisions?

    Homework Statement Calculate the minimum beam energy in a proton-proton collider to initiate the p+p→p+p+n0 reaction. The rest energy of the no is 547.3MeV.Homework Equations For a head on collision between particles a and b, from conservation of total energy: Ex = Ep + Ep' = 2Ep so that...
  5. B

    Calculate force required to tip beam on a rope w/ friction

    Homework Statement The uniform I-beam has a mass of 74 kg per meter of length and is supported by the rope over the fixed 300-mm drum. If the coefficient of friction between the rope and drum is 0.50, calculate the least value of the force P which will cause the beam to tip from its horizontal...
  6. T

    Explaining Bending Stress in Cantilever Beams

    Hey everyone, I was just wondering if someone could explain to me what Bending stress is? Supposed you have a cantilever beam with a point load at the free end, I know that the bending stress will decrease as you move away from the fixed end? but why? and how can you back that up? Also, as...
  7. S

    Multiple distributed loads on a beam

    Hi all, my professor has hinted at proposing a question of this sort to us for a shear and bending moment diagram. Now while I am comfortable with having [either] a uniformly distributed load or a varying one, I'm not sure how to deal with both. I can't seem to find anything in my textbook to...
  8. Vircona

    How to Determine Maximum M and T in a Cantilever Shaft?

    Hey, all, So I posted a similar thread yesterday about my project design issue, but I've made progress on it by taking a different approach. For the project, I have a cantilever shaft of fixed length (1.2m) and a tensile axial loading, and two torsional loadings in the same direction at...
  9. T

    Fourier series, is this valid?

    Hi, I have a Fourier problem that i do not know if it is valid to do the calculations like this. The Fourier transform looks like this ## \hat{v}(x,\omega) = \frac{\hat{F}(\omega)}{4(EI)^{\frac{1}{4}}i \omega^{\frac{3}{2}}(\rho A)^{\frac{3}{4}}}\left[ e^{-i\left[\omega^2 \frac{\rho A}{EI}...
  10. S

    Path of Light Beam in Plane Parallel Plate

    Homework Statement In plane parallel plate the refractive index is a function of coordinate ##z##, so that ##n=n_0 -{n}'z^2## for ##{n}'>0##. The origin of the coordinate system is in the middle of the layer, and ##z## is parallel to the normal of the layer. In paraxial approximation calculate...
  11. C

    Calculate Torque for 8N Forces on 0.6m Beam

    Homework Statement Two 8.0N forces act at each end of a beam of length 0.60m. The forces are parallel and act in opposite directions. The angle between the forces and the beam are 60 degrees. What is the torque of the couple exerted on the beam? 1. 2.4Nm 2. 4.2Nm 3. 4.8Nm 4. 9.6Nm Homework...
  12. T

    Calculating Transverse Wave Propagation in a Semi-Infinite Beam

    1. A transversely directed transient force F(t) acts at the free end of a semi-infinite beam. a) Show how displacement, velocity, acceleration and strain at an arbitrary position along the beam can be determined. b) Calculate (MATLAB) the transversal acceleration (or an other quantity) at an...
  13. S

    Powell Lens Equations for Gaussian to Flat Top Beam Conversion

    I am a Post graduation student and I am doing a project on the conversion of a Gaussian beam into a flat top beam using optical components. I have found that the best component to do the same is a Powell lens. I would like to know more about the equations connecting the input beam diameter...
  14. T

    Calculating Deflection and Stress in a Tapered Cantilever Beam

    Hey all, So I have this beam problem and I honestly am lost with it! The beam is I-section cantilever, tapers in depth along its length (See picture attached) with a point load at the free end. I am trying to figure out the deflection formula and how to derive it! Also, when calculating its...
  15. spovolny

    Free Beam Bending: Find Complete Answer & More

    Consider a beam with an upwards concentrated force applied to its center. This is equilibrated by a distributed downwards force. There are no displacement boundary conditions. I've tried approaching this with simple beam theory, but I can't get a complete answer (shear, moment, slope...
  16. P

    Continuous beam deflection (structural)

    Homework Statement Using continuous beam theory, constructing BM diagram from points b to c, to calculate the max deflection. I only found a have a single solution, though the BM digram show two points of zero bending. I can provide the solution. [edit: Rb = 685 N] Homework Equations...
  17. C

    Can Magnetic Beams Enable Faster Space Travel?

    Hey all, So I've been writing a hard science fiction novel and need real answers from someone who understands the fields better than I ( I have no formal education outside basic high school classes in physics) The problem I have is I'm not a fan of faster than light travel but I need a way for...
  18. C

    Wavefunction normalisation for proton beam

    Homework Statement Calculate the normalization parameter A in the wavefunction ## \varPsi(x,t) = A e^{i(k\chi - \omega t)} ## for a beam of free protons traveling in the +x direction with kinetic energy 5 keV and a density of ##7.5 * 10^9 ## particles per meter beam length. Homework...
  19. E

    Maximizing Higgs Particle Travel: Insights on Acceleration and Detection

    When you accelerate higgs.. would it travel the same as photon with alternating magnetic and electric field traveling on permissitity and permeability of the vacuum. In other words, how do you make scalar particles travel? If we can make really sensitive Higgs detector.. then you make higgs...
  20. J

    Constructing a Bending Moment Function Using McCauley's Method

    I have A beam of 1.2 m long, supports at 0m and 0.8 m. forces of 10 N at 0.4 m and 5N at 1.2 m I need to find the deflection equation for this situation. Can someone have a look and see if they can come up with the equation. As I have tried but my results do not match what I am expecting
  21. A

    How does length affect the bending of a horizontal beam?

    Homework Statement We were shown this image ^ We were later told that it is suggested that the depression (y), is directly proportional to the length of the beam cubed (L3). We were asked to give reasons why this is so. EDIT: The 1kg mass is placed at L/2 Homework Equations y is directly...
  22. C4l1

    How Can the Euler-Lagrange Equations Describe Light Path in Optical Fibers?

    Homework Statement An optical fiber is one way to guide light efficiently from one point to an other. It is currently used for data communication: it offers low loss and very high bandwidth, ideal for the requirements of the internet. Generally, we can describe an optical fiber as a medium with...
  23. N

    Deflection of a Beam: Solving for vB using the Double-Integration Method

    Homework Statement For the simply supported steel beam [E = 200 GPa; I = 129 × 10^6 mm4], use the double-integration method to determine the deflection vB at B. Assume L = 4 m, P = 60 kN, and w= 40 kN/m. Can someone please help, when I insert x=2m into the equation i derived for M, and then...
  24. Valerie Prowse

    Equilibrium problem - Vertical beam, cable

    Homework Statement A uniform vertical beam of mass 40 kg is acted on by a horizontal force of 520 N at its top and is held, in the vertical position, by a cable as shown. a. Draw a free-body diagram for the beam, clearly labeling all of the forces acting on it. b. Calculate the tension in the...
  25. George Zucas

    What is an I55 beam and how does it compare to other common beam types?

    I was supposed to measure a beam at a far away worksite but after a series of unfortunate events, I wasn't able to. All I know at the moment is it is referred to as I55 beam. I searched for it using every combination of words I can think of but cannot find it. We normally don't use beam...
  26. P

    Suspended Beam: Solving Homework with Unknown Equations

    Homework Statement Homework Equations I do not know exactly. The Attempt at a Solution I honestly have no idea how to approach this.
  27. A

    Uniform beam reinforced with iron, how to approach?

    So I am starting to learn for the final exam a bit early and I am trying to do this problem with a uniform beam which is reinforced with iron inside. I know how to calculate this if it wasn't for the reinforcement within the concrete. I know that the purpose of the iron reinforcement is to...
  28. R

    Focal length of 2 lenses to reduce laser beam diameter

    I need to reduce the beam diameter of a laser I am using. I plan to do this by first passing the beam through a positive spherical lens with focal length f1 and then a negative spherical lens with focal length f2 and f2 < f1. By placing the lenses so that the two focal points overlap I will have...
  29. S

    Simple Beam Bending - Where am I going wrong?

    I am trying to find the width of a square hollow structural member that can withstand the forces above. However, my calculations are showing me that a square hollow aluminum tube of 4 mm by 4 mm with a wall thickness of 1/16 of an inch would be adequate, which I don't believe. Is anyone able...
  30. A

    The smallest angle flashlight beam can make with horizontal

    Homework Statement At the aquarium where you work, a fish has gone missing in a 10.5m -deep, 9.45m -diameter cylindrical tank. You shine a flashlight in from the top edge of the tank, hoping to see if the missing fish is on the bottom. What’s the smallest angle your flashlight beam can make...
  31. C

    Calculating normal stress in a beam

    Hello So I've done some calculations, I'd like to see if my stuff is right. Thanks :) Please view attached http://i.imgur.com/AfMZyr0.jpg area = (pi)(9^2) = 254.46 Cos53.13=15/CG CG=25kN Normal stress = 25000/254.46 =98.25
  32. K

    What is the force at the joint C on the right beam?

    Homework Statement Pay attention that the left support A is a fixed axis and the right, B, is a free moving axis. C is a joint. The left beam (to the joint): 2m, 6[kN], the right beam: 3m, 10[kN]. What is the force F. Homework Equations Moments: ##M=F\cdot L## The Attempt at a Solution To...
  33. K

    Tensions in Hanging Beam with Given Weights

    Homework Statement The weight of the beam is 2000N, the masses: m1=200kg, m2=300kg. What are the tensions in the ropes. Homework Equations Moments: ##M=F\cdot L## The Attempt at a Solution Moments around A: $$\mbox{and}\left\{\begin{array}{ll} 1.5\cdot T_B+1.2\cdot T_B+0.6\cdot T_A=1962\cdot...
  34. A

    Shear, bending, and stress in a beam; Please explain

    Homework Statement Homework EquationsThe Attempt at a Solution I can't understand the solution and what is the variable "X" !
  35. T

    Random question -- if a laser beam did not spread out

    Assume I have an ideal laser pointing which light will always move parallel to where the laser pointer is pointing. This mean that no matter how far I stand away from the laser pointer, I will see the same spot of light with the same light and intensity. In that case is it possible to determine...
  36. K

    Free body diagram of a beam construction

    Homework Statement Beams AC and BD are light (no mass) and they're conjoined at B. Points A and D are fixed but frictionless. The radius of the wheel is R and the weight hanging on the pulley has the mass m. Homework Equations Fx=0 Fy=0 M=0 The Attempt at a Solution I'm stuck at the very...
  37. A

    Bending moment Diagram for fixed-fixed beam

    Homework Statement There is a beam, say length L, with a force F UP on the left built-in support and a CLOCKWISE moment. The right side has a force, F, DOWN and a COUNTERCLOCKWISE moment i.e F up, cw moment -------------------------------------------------------------F down, ccw moment...
  38. K

    Creating a spring using only beams

    Attached is my ANSYS model of a spring made using cantilever beams. In playing around with with different dimensions, I noticed that the longer I made the connecting section (dirty green section) the less of a total deflection there was. Could someone explain to me why this is? The overall goal...
  39. N

    Why is the maximum bending stress not at the center of the beam?

    This isn't a homework question. I just have a thought I'd like an answer to. When I think of a bending beam it's obvious to me that the point on that beam which is under the most stress would be the center ( assuming equal loads on each side). my question is what is the scientific explanation...
  40. K

    Need help with more indepth beam theory?

    I have a project for a class and our goal is to design a beam using 1018 steel to achieve a certain deflection under one load and not fail under an even larger load. The design I have come up with is very similar to a cantilever beam, but is has a variable cross section. I have used the...
  41. I

    Solving a Laser Beam Deflection Problem Using Equations

    Dear all, I have pretty simple problem in terms of understanding but I can't write an analytical solution. Consider you have a laser beam (without divergence, single wavelength). You can see the intensity distribution on the screen perpendicular to the beam. Then you insert a thin glass layer...
  42. J

    Bucklig: deflection at Euler load

    Hello I was trying to calculate the horizontal deflection of the free end of vertical clamped beam. The beam would be loaded at the free end with a horizontal force H and a vertical force P. My idea was to calculate an initial deflection due to the force H. Then calculate the additional...
  43. S

    Calculating shear stress in a beam?

    The equation for shear stress as I know it is VQ/It where V is the shear force, Q is the first moment of area(?), I is moment of inertia and t is the length of the section in question. My question is, is there a general formula for Q? In my Solid Mechanics notes I've written that Q = ∫y.dA but...
  44. J

    Solve Torque Beam Problem: Mass Calculation

    Homework Statement The beam is 47 cm in length. The other length measurements are R1 = 11 cm, and r2 = 26cm. The mass of the beam is 6.0 kg. Determine the mass on the beam. Homework Equations τ= F(R)Sinδ ( don't know if the circle thing is theta closest one i could find for it. The Attempt at...
  45. T

    How to Estimate Vibration Stop Time for a Decelerating Cantilever Pipe?

    Hi there! Im trying to do an analysis in Abaqus of a cantilever pipe, with a tip mass at the free end, that is decelerating to a stop at 10 m/s2 from 10m/s, causing it to vibrate. To validate my results I am doing some handcalcs. I have done a static analysis and calculated the maximum...
  46. C

    Why is Normal Area to Light Rays Invariant?

    It is a fact that all inertial observers would measure the same area normal to a beam of light rays in relativity. You can prove this by considering the displacement vector connecting a light ray to its neighbouring light rays. But I wondered if there were some intuitive explanation of why this...
  47. B

    Forces on a beam, replace with force and couple

    Homework Statement http://oi58.tinypic.com/2a5d4w3.jpgHomework Equations [/B] So I can just sum up all the forces then sum the moments?The Attempt at a Solution [/B] FBx = 0 lb FCx = 800 cos30 = 692.82 lb FEx = 0 lb FBy = -2500 lb FCy = 800sin30 = 400 lb FEy = -1200 lb Resultant force: FAx...
  48. A

    How to split up a photon-neutron beam?

    I need urgent help! we have a beam made of some neutrons and some photons. I thought about the beryllium polycrystaline but I'm not really sure it could work. The beam has an energy of 2 MeV moreless. Sorry for my spoken english.
  49. K

    Reaction force on a leaned beam

    Homework Statement A beam of 12[kN] is on a smooth floor on one side and on a rough edge on the other. The total length of the beam is 10[m]. What is the reaction on the edge. Homework Equations Moments (torque): F1L1=F2L2 The Attempt at a Solution I drew the forces. the reaction on the floor...
  50. terryds

    Understanding Normal Force Direction in Leaning Ladder & Cable Beam Systems

    I know that normal force is a reaction force. http://www.sumoware.com/images/temp/xzhhpaacgkdktjna.png In the leaning ladder problem, the normal force is perpendicular to the floor and the wall. But, in the cable and beam problem, why isn't the normal force perpendicular to the wall ...
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