What is Bending: Definition and 665 Discussions

In applied mechanics, bending (also known as flexure) characterizes the behavior of a slender structural element subjected to an external load applied perpendicularly to a longitudinal axis of the element.
The structural element is assumed to be such that at least one of its dimensions is a small fraction, typically 1/10 or less, of the other two. When the length is considerably longer than the width and the thickness, the element is called a beam. For example, a closet rod sagging under the weight of clothes on clothes hangers is an example of a beam experiencing bending. On the other hand, a shell is a structure of any geometric form where the length and the width are of the same order of magnitude but the thickness of the structure (known as the 'wall') is considerably smaller. A large diameter, but thin-walled, short tube supported at its ends and loaded laterally is an example of a shell experiencing bending.
In the absence of a qualifier, the term bending is ambiguous because bending can occur locally in all objects. Therefore, to make the usage of the term more precise, engineers refer to a specific object such as; the bending of rods, the bending of beams, the bending of plates, the bending of shells and so on.

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  1. C

    Bending stress of beam in contact with a flat surface?

    I am designing a spinal disc with 2 metal endplates. These endplates are rectangular in shape and are fixed to form a flat contact surface with the vertebrae bone surface. My question is based on the bending stress of these metal endplates. I need to work out the possible thickness of these...
  2. C

    How Should Bending Stress Be Calculated in a Spinal Disc Endplate Design?

    http://img341.imageshack.us/my.php?image=endplateballsocketij7.jpg" I am designing the appropriate size of an upper endplate for a spinal disc and was wondering what would be the best way to calculate bending stress in this design. The image is shown in the link above. It is a ball and socket...
  3. O

    Is Time Bending the 3rd Dimension in Spacetime Curvature?

    http://en.wikipedia.org/wiki/Image:Spacetime_curvature.png" The picture linked above shows the spacetime curvature. Apparently, it's a 3d model. But it's not! What i think (and basically trying to find out about) is that space itself is imagined as the 2d grid. What the Earth does is...
  4. R

    Formula involved in calculating Flexuliar Bending

    Hi! I'm new. I was just want to size Cloumn using a steel which carries a sign board area of 16.60 sq. m and a wind velocity of 130 Km/hr. is it possible to caculate the stress using those two (2) given? Thank you
  5. Saladsamurai

    Shear and Bending Moment Diagrams

    Shear and Bending Moment Diagrams! Homework Statement Homework Equations Newton's 2nd and 3rdThe Attempt at a Solution So my main confusion is this: I found the reaction at A to be 19 kN If I make a vertical cut through some arbitrary point along the beam and and do some analysis I get...
  6. G

    Steel Tube Bending: Gai Abraham's LEV Automotive Engineering Question

    My name is Gai Abraham, an automotive engineer trying to build a little LEV (low emission vehicle) I have contacted you previously and I wish to ask further help on the bending of steel tubes. Namely I have designed a chassis from bent steel tube, the technical sheet on S.S. astm 301...
  7. W

    Calculate Min Drum Diameter for Copper Strip 4mm Thick, max Stress 332MN/m2

    Homework Statement 3. Calculate the minimum diameter of drum on which copper strip 4mm thick may be wound if the maximum bending stress is not to exceed 332MN/m2. Assume E = 95 GN/m2 σ /(yxE)=r Homework Equations The Attempt at a Solution would this work if so i make it...
  8. M

    Shear Forces and Bending Moments in Beams

    Homework Statement (Q) A beam 4m long is supported at the left hand side by a hinge support and on the right by a roller support. It is under a non-uniform load intensity throughout by a load intensity given by: w = 25Cos(pi x/8)kN/m. Write equations for the shear force and the bending...
  9. S

    Shear force bending moments diagram help?

    Homework Statement It's number 4 I'm doing Homework Equations ΣmomentA= 0 ΣFx= 0 ΣFy= 0 The Attempt at a Solution i've got the correct answers i think, but I'm not sure how to draw the shear force and bending moment diagrams because of the moment that's included. i did draw...
  10. W

    Verify my calculation, bending moment torque

    I made a diagram with the calcs on it, should be fairly simple, I just need to make sure I'm doing it right or if I'm way off. link to the diagram These are the beginnings of my homemade engine dynamometer...I thank you for your assistance.
  11. M

    What Happens When You Bend a Plastic Cup?

    I was drinking from a plastic cup today with some physics friends, and we noticed that when we bent the cup, a white patch of plastic would form there, and the plastic would not be transparent at that point anymore. We were baffled by this observation, and none of us could really explain what...
  12. marcus

    Lambda contibutes to bending (says Wolfgang Rindler)

    http://arxiv.org/abs/0709.2948 The Contribution of the Cosmological Constant to the Relativistic Bending of Light Revisited Wolfgang Rindler, Mustapha Ishak (The University of Texas at Dallas) 5 pages, 2 figures (Submitted on 19 Sep 2007) "We study the effect of the cosmological constant...
  13. I

    Thermal Expansion with bending bars

    Well I'm having problems trying to understand this problem with a bending bar in my textbook. Since we barely touched the subject of thermal expansion in class (there were no examples on this kind of problem) I'm a little confused. The hint in the problem makes no sense to me and gets me no...
  14. V

    Bending Rectangular Cantilevers Under Gravitational Force

    Hello, actually, I am looking for some data concerning horizontal cantilevers that bend under the influence of the gravitation force. The cantilever should be rectangle-shaped, with given young-modul, poisson-ratio and of course measures. In addition to that, the deformation of the cantilever...
  15. G

    Equations for Bending and Deflection of a Beam

    bending for beam -- deflection Homework Statement bending for beam -- deflection Homework Equations The Attempt at a Solution
  16. J

    Checking a Problem: Speed of Bending Rod Tip

    I made up a problem and wanted to make sure that I did everything right. A thing rod with mass M is bent into the shape of a quarter circle with radius R. It is positioned so that it looks like the arc made as theta moves from terminal position (+ x axis) to 90 degrees counterclockwise. I...
  17. D

    Bending Guitar Strings: Learn How to Make a Synth Effect

    Hi everybody I’m currently making/coding my own guitar synthesiser and I are interested in creating a 'bend' playing effect. By modifying the tension of guitar strings I presume I will be able to change the rate in which sounds travels in these strings. From playing guitar myself I thought...
  18. H

    Calculating Light Bending by Gravity: Can You Teach Me?

    Hey all. I was wondering what is the math behind calculating how much light is bent by gravity/curvature of space. Can someone teach me?? thanks
  19. X

    General Cantilever Equations for Bending Aluminum

    I am trying to determine some general cantilever equations. I have an aluminum beam extending out 235 mm (L) from an aluminum block. The beam is 25 mm wide (W) and 3 mm thick (H). A force is applied at a point approx. 200 mm from the block and I am interested at a point 25 mm away from the...
  20. A

    Calculating Bending Moment & Torque from Mohr's Strain Circle

    Hi, desperately need help with this assignment question as its in for 2moro! "At a point on the surface of a shaft with diameter of 100mm, a 45deg rosette strain gauge is positioned with the middle gauge along the axis of the shaft. The gauges measure strains of a= -0.00015, b = 0.0003, c =...
  21. P

    Beam Bending & Stress: Solve 2 Cantilever Problem

    I'm stuck on a beam bending problem I have. I have 2 cantilever beams one one top of the other applying a force. I need to know find the stress on the left hand beam and the deflection. I have the formulas (using Roark's formulas of stress and strain) but there's nothing about two cantilevers...
  22. L

    Help Needed: Determine Bending Moment at 0.600m from Roller Support

    hey every1... I'm really really stuck on this problem and unless i get it and a few others right I am going to fail my engineering statics course :( Any help would be apreciated so much... The Question that goes with that diagram I've attatched is: Determine the bending moment at a...
  23. F

    Drawing Bending Moment & Shear Force for a Beam w/ Constant Moment

    Can anyone draw me a correct Bending moment diagram and shear force diagram for this beam? i have drawn the shear force diagram for this case but I do not know how to draw the bending moment disgram for this case because this question involve a constant moment. Normally the rule for bending...
  24. T

    Calculating Shaft Diameter for Bending & Torsion Loads

    what formula should i use to calculate the shaft diameter according to the load due to bending and torsion??
  25. T

    Calculate Bending Moment & Stress of Axle w/ 300N Load

    Calculate the bending moment in the centre of the axle?? What limit stress is valid for this loading case ? may i know how to form the moment eqn?? F=300N picture - http://files.filefront.com//;5410274;;/ pls help thanx
  26. T

    Limit stress and bending moment

    Calculate the bending moment in the centre of the axle?? What limit stress is valid for this loading case ? picture - http://files.filefront.com//;5410274;;/ pls help thanx
  27. T

    Finding Maximum Deflection of Bending Curve

    if i have a bending curve eqn of w'(x) = (q/6)<x-l>^3 - ql/4 <x-0>^3 - 3ql/4 <x-l>^2 + (9ql^3)/24 suppose to find the deflection of maximum of the beam, we have to set w'(0)=0 .Am i right?? then if it is right,how can i find the value for x on which the max bending occur because i don't...
  28. T

    Bending moment and shear force diagrams

    http://www.sendspace.com/file/czhuhx http://www.sendspace.com/file/gviky7 pls have and look at the link above and kindly tell me how to draw the bending moment and shear force diagrams.this is in the chapter of statics mechanics thanx
  29. C

    Why Does a Beam Bend Only About the Centroidal Axis?

    in beam bending the resistance of a cross section is measure by moment of inertia about centroidal why. How do we know that the bends only about the centroidal axis . Any detailed discussion on this?
  30. T

    Maximum bending moment for statics

    for statics , in the bending moment diagram,or the shear stree diagram how can i find maximum bending moment ?? any condition for that??or any recommended websites with diagram is appreciate thanx
  31. I

    Bending property solid metal pipe vs hollow metal pipe

    i wanted the techinical information. bending property of solid pipe and hollow pipe with same diameter. which will bend more and why ? i wanted the technical answer please help me out :smile:
  32. T

    Shear force and bending moment

    does anybody has any websites or relevant material on how to draw the shear force and bending moment diagram?? pls help... thanx
  33. V

    Shear Force and bending moment diagram

    Hi guys, For a Engineering Project, we will be suspending a bridge using a cantilever system. We have to draw the shear force diagram (SFD) and bending moment diagram (BMD) for the horizontal and vertical members. The arrows on the diagram represent the loading from the bridge itself. I...
  34. B

    Gravity & Light: Bending the Laws of Physics

    At what mass does an object start to noticeably bend light?
  35. B

    Can note bending on a trumpet be explained through physics?

    For a physics research project I am doing the physics of note bending on the trumpet. Basically without pressing any valves I can bend a middle C to B natural. I am having problems finding any materials that talk about this except in passing mention. Such as, experimentally there are problems...
  36. K

    Bending of Light around a Star

    I know that the formula for the angle of bending of light around the star \theta \; in radians is: \theta \; = \frac{4GM}{rc^2} This is equal to full bending of light, half of which occurs on the rear side of the star and the other half occurring on the foreground side. So half of this...
  37. O

    Solving a Bending Moment Question: R1 = 110kN & R2 = 141kN

    Hi, I've got a little problem with a bending moment question. Here it is (really sorry for the bad diagram!) http://img474.imageshack.us/img474/7844/help15eu.jpg" R1 and R2 are reactional forces, which using moments I have calcualted to be: R1=110kN R2=141kN Section A of the...
  38. R

    Light bending around neutron and bound photon

    I assume that the neutron is a particle with finite size and is <really> a single particle (that is that it does not have any further structure or components-like nucleus) and lastly it is electric nutral. I hope that these assumptions are close to the experimental observations. I am making life...
  39. C

    GR, time-like energy, and photon-path bending?

    Does time-like curvature of spacetime cause light to bend, for example, around the sun? Or is the gravitational bending of light only due to the space-like curvature? So far, I understand the concepts as: Time-like curvature is caused by the mc^2 part of E, while space-like curvature is caused...
  40. U

    Statics: Shear force and Bending Moment

    I need to understand how to work this type of problem before my final exam. How do you find the Maximum shear force and Maximum bending moment? Thanks
  41. michael879

    Sun Bending Light: Gravity Warps Space-Time?

    wasnt the fact that the sun bends light coming from distant stars proof that gravity warps space-time? I am sure I am wrong but can someone explain to me how they know it wasnt just refraction of the light as it passed the sun's "atmosphere"? Light bends around Earth due to our atmosphere and...
  42. E

    Can Chromatic Aberration Create Gravitational Fields?

    Ok We All Know That A Gravitational Feild Can Bend A Beam Of Light Now Can The Reverese Of This Be True? Can A Bent Beam Of Light Produce A Gravitational Field ?
  43. C

    Moment-beam under bending momen?

    A beam is under bending. Let us take a small part of a beam with length x. It has end A and end B. At end A the bending moment is M1 & shear force is S1 and at end B the bending moment is M2 & shear force is S2. Let me take the moment equilibrium for this element about B. M2-S2-M1+S1=0...
  44. K

    Bending load limits, aluminium extrusions?

    Hi I want to determine the bending load limit to elastic failure of extruded aluminium square section, 50 mm sq, warious wall thickness, 1, 2, 3, 4, 5 mm I thought I could get a good estimate from the tensile strength. I found a value of 90 Mpa for commercially pure aluminium but doubt...
  45. S

    Light Bending Effect in General Relativity: Understanding Gravitational Lensing

    In GR the bending of light around a Large Mass produces a Gravitational Lensing effect. I have a gedanken, I have a light source that has a finite 'ridgid' beam, a L.A.S.E.R beam. I point the beam into the night sky, at a location to the far West Horizon. I now proceed to arc the beam across...
  46. X

    Minimum bending radius for a tube

    How do you calculate the minimum bend radious for a tube? Its a SS tube and we want to bend as small a radius as possible...
  47. D

    Mechanics of Materials Bending Stres Problem

    Mechanics of Materials Bending Stress Problem Hi, I have a homework problem for mechanics of materials involving bending stress. Here is the exact wording: "Show that the maxiumum bending stress for a beam of rectangular cross-section is Omax = Mc/I [(2n + 1) / (3n)] if instead of...
  48. J

    Schottky contacts - band bending

    Hello! I am looking a bit at the Schottky contacts, metal-semiconductor, and I am starting to get a hang of it, but some things are missing. Specifically: Why must the distance from the Fermi Energy to the vacuum level in the metal and the distance from conduction band edge to vacuum...
  49. E

    Help Needed: Modeling Beam Bending with Electrostatic Forces

    Hey-- I'm trying to model the bending of a beam due to electrostatic forces. (Femlab does offer this model on their website, but the module I'd need to run it costs $600!) I have no problem modeling a beam bending, and I have no problem creating a parallel plate capacitor, but when I...
  50. O

    Bend a Laser Beam - Learn How It's Done

    Bending a laser beam ?! I was surfing the web when I encountered this photo: http://www.ieav.cta.br/soldagem/LASER%20verde.gif I can only read English and Persian, unfortunately the page was in another language I can't get even a word of it. Anyway I'm badly interested to know a bit...
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