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. M

    Calculating Shear and Bending forces in a Cantilever Beam.

    Homework Statement I am trying to work out the Shear force and bending moments in a simple cantilever bean with a point load and a U.D.L but am not sure of the equations or how to go about starting it. Its a 2 m long cantilever beam built into a wall at the right-hand end, Point C. A UDL is...
  2. G

    Help me calculate a calculated bending stress (psi) in cantilever beam?

    Homework Statement I am using a Vishay strain indicator with it hooked up to a strain gage hooked up 1" away from the wall on the solid beam. The beam is .5" by .5", and it is solid. The beam is 16" long and I am putting weights at the end of the beam. The weights are 1, 2, 5, 10, 15, and 20...
  3. M

    Stress concentration factors for hollow shafts under pure bending

    Hi everone, I am trying to make a rough estimate of fatigue life of a hollow shaft under pure bending at a particular load level.The hollow shaft has a shoulder fillet. The minuimum outer diameter is 69mm and the maximum outer diameter is 72mm with a transition radius of 6mm.The thickness of the...
  4. T

    Analyzing Cantilever Beam Bending: Is My Solution Accurate?

    Homework Statement The Attempt at a Solution Is my work correct?
  5. Z

    How to Determine Reactions at Points in Beam Analysis?

    Homework Statement Neglecting the size of the pulley at G, draw the shear and bending moment diagrams for beam AB. Homework Equations Fxnet=0 Fynet=0 Netmoment=0 The Attempt at a Solution\ What I want to do first is figure out the reactions at A and C, however I'm not sure...
  6. U

    Bending of two Square beams and side plates in contact

    hello all I have this problem to solve in ansys workbench 13 (Im new to this software): two parallel 5000mm length square beams in contact 200x80x8 (EN10219: structural hollow sections ) in frictionless contact and on the sides two side plates. At the ends I have two suports and I have on top...
  7. P

    Combined Bending & Torsion

    I have recently done a lab at university which studied the effects of combined bending and torsion. It was conducted using a Hi-tech HSM.11 piece of equipment. We applied loads at a series of angles, 0deg, 45deg and 90deg. We then worked out our principle stresses and yields. One of the...
  8. J

    Statics Shear Force and Bending Moment Diagrams Problem

    Figured it out.
  9. B

    Deriving Bending Moment Diagrams from Shear Force Diagrams

    Folks, I was checking to see was it possible to determine the bending moment diagram from the shear force diagram. Seemingly one can do it for simply supported beams but if we consider a rigidly supported beam on either end its not possible to derive the bending moment diagram from the shear...
  10. B

    Arch Bridge Shear and Bending Moment?

    This is my first course in Engineering and the professor told us today that we have to do shear and bending moment diagrams for an arch bridge. Anyone have any clue on how to do this? He gave us no information on how to do it and nothing in a book. Please help??
  11. L

    How are Shear and Bending Moment Equations Derived from Distributed Loads?

    Homework Statement draw/find the shear and bending moment diagrams of: Homework Equations V : shear M : bending moment ω : distributed load The Attempt at a Solution i already understood how the solution worked but i can't quite understand how the equations with the boxes were derived
  12. V

    Bending of light in a uniform gravitational field

    Homework Statement This is supposed to be a simple problem that shows that light bends or gets pulled in a gravitational field. A light pulse emitted in the positive x direction travels 10 s in a uniform gravitational field of 100 m/s^2. the gravitational field points in the negative y...
  13. R

    Bending of a varrying cross section

    Recently, I had lab. In the lab we took different objects and measured their strain. One object had a varying cross section. The data for strain was recorded. Right now, I'm trying to make a stress strain graph, but the problem is my equation for stress. I don't know how i can take my moment of...
  14. S

    Bending Moment in two directions

    Not Really a homework question but it will help with how i go about the homework. So i have a beam coming out of the wall and it has force acting on it like this: Woops, that 20 on the side view should be a 10 :P What i want to find is the total moment at the mid point. I know how to find...
  15. D

    Understanding Bending Moments and Second Moment of Area | Calculation Analysis

    Hi, I just wanted to know if I have answeedthis question correctly, if not where I have gone wrong. Thank you. [PLAIN]http://img148.imageshack.us/img148/6245/secondmomentofarea.jpg From what I have calculated, none are acceptable, but my calculations may be wrong
  16. R

    Bending moments and deflections, safety factors and inertia which to calculate?

    Homework Statement Q: A beam has a solid square cross section of 100 mm and is simply supported by two supports 3 m apart. Calculate the dead load that can be safely supported when applied to the middle of the beam. * The question doesn't state material but I'm informed that it is mild steel...
  17. F

    Band Bending & Donor Concentration in Semiconductors

    When a n-type semiconductor is brought into contact with a metal, then alignment of the chemical potentials of both systems leads to band bending within the depletion layer, e.g on the semiconductor side. does the amount of band bending (change of potential) also depend on the donor...
  18. C

    Real world prob: bending of 26mT circular plate

    Hello all, I'd like to check my work on this to make sure a safe lift is done. We have an 11m diameter, 35mm thick, 26mT circular steel plate to which we will add two trunions at the ends. The circular plate is welded in 4 parts and once we weld one side we have to flip to weld the other. That...
  19. Philosophaie

    Gravity bending due to another Gravitational Source

    Does the effect of Gravity get bent like light around another gravitational source? If the object is close enough to the Earth does the Earth's gravitational force bent the Moon's or even the Sun's gravitational effect on that object before that "line of sight" event occurs. As Einstein's...
  20. B

    Formula to Calculate Bending Moment of Beam Under UDL and Point Load

    Homework Statement 1.What is the formula to calculate the bending moment of a beam subjected to UDL? 2.What is the formula to calculate the bending moment of a beam subjected to point load? Homework Equations Bending moment (UDL) = WL^2/8 (Kg-mm or Kg-m) Bending moment (point load) =...
  21. M

    Bending moments diagram at T intersection

    Homework Statement Draw the axial force, shear force and bending moment diagrams. Show the locations and magnitude of the maximum and minimum values. Homework Equations See diagram. The Attempt at a Solution I've worked out the values from points A-B and then from points B-D. I...
  22. D

    Bending Moment on Pole due to Wind

    Hello Friends. I have a question for the following scenario: There are two wooden poles, both set into the ground so that they are sticking straight up. The height of Pole One is H1 feet. The height of the Pole 2 is H2 feet. Supported in between these two poles is a wire. The ends of the...
  23. S

    Calculating Re-acting Forces of 10m Beam w/ 3 Forces & Bending Moment Diagram

    Question : A beam 10 meters long, with 3 forces acting on it and 2 re-acting forces on it to keep it in equilibrium. The re-acting forces are at 2 meters from either end. The forces onto the beam are at 3 meters from the left end of 10kN, 10 meters from the left end of 20KN and a distributed...
  24. G

    Bending stress in gear/bearing puller

    Homework Statement I have a project where I have to determine the bending stress on a gear/bearing puller. It looks like this: http://www.posilock.com/PDFs/106.pdf . The free body diagram I'm pretty sure would look something like this: http://img20.imageshack.us/img20/1918/fbdi.jpg...
  25. S

    Calculating Bending Moment of Pinned Beam: Is it Negative?

    I have just calculated the bending moment of a beam for every metre over a 10 metre length, the beam is pinned at both ends. Is it possible for the full diagram to be Negative?
  26. G

    Local bending stress calculation in long beams

    Hi everyone, Recently I faced a problem in calculating bending stress in a long UPN profile "flange" due to concentrated force. It seems that the regular/familiar formula for bending stress in a finite/short element does not applicable in local bending of long/infinite beam. See sketch...
  27. C

    Plate Bending Analysis: Point Load Distribution

    Hello. First time on the forum. I have a plate being supported off a series of beams (see pdf). The beams are close together and restrained. The plate is simply supported on all sides and the beams simply supported. The plate is to be used to distribute a point-load over the beams and is...
  28. P

    How can I estimate the bending stress for a hollow tube under uniform load?

    Dear All, Please see the picture. I need to find the bending stress for that profile. Its hollow tube dia= 38 mm, 4 mm thick. its is acted with udl of 500 N/m2 on its outer surface. How can I estimate the bending stress, deformation. Assume it as mild steel with E = 200 Gpa, poission...
  29. D

    Bending and deflection of composite beam

    my question is regarding calculation of deflection of a composite beam, ie a beam with a cross section made up of 2 separate homogeneous materials. the methods i know for calculating deflections in homogenous beams are energy methods(catiglianos 2nd) and the elatic curve equations(second...
  30. S

    Trouble Understanding Bending Moments?

    I'm having trouble fully understanding bending moments. I get the calculations, the force times distance (lever arm), and how to calculate the bending stress (M*y/I). Its the orientation/direction that I am having trouble picturing in my head. I know this is pretty basic, but I just haven't...
  31. S

    Calculate Maximum Bending Moments & Stress

    Can anyone help me calculate the maximum bending moments and maximum stress for the figure i uploaded please.
  32. W

    Light Bending: Comparison of Theories

    In the essay „Über die Ablenkung des Lichtes I am Schwere*feld der Sonne“ ( http://adsabs.harvard.edu/full/1931ZA...3..171F ) the authors - Freundlich, Klüber and Brunn - presented 1931 graphically the results of three expeditions, which took place 1919, 1922 and 1929. They put together all...
  33. Eagle9

    Maximum bending moment in blade

    Imagine that the electro motor is rotating the blade in air at sea level: http://img822.imageshack.us/img822/4655/222on.jpg During this rotation the air impedes the blade’s rotation and if the blade rotates too quickly or if it is made of fragile material rod will be simply broken or bent...
  34. D

    ANSYS Bending Moments Calculation

    Dear All, I have been trying to calculate the bending moment redistribution on continuous, steel fiber reinforced, beams. The idea is simple, introducing to the ANSYS model elements, with lowered E-modulus, according always to the evolution of the cracking observed on the actual tests...
  35. O

    Bending of a parabolic plate with some thickness

    Hi, I am trying to obtain a relation for calculating the deflection of a parabolic plate of thickness (say 't') clamped at one end, with a concentrated load along the center line at the "apex" end. Any direct links for the formula? Thanks!
  36. B

    Calculate Bending Moment of Wooden Joist - 1.0 & 2.0 m

    3) A wooden joist of rectangular cross-section spans a gap of 5.0 m and supports a load of 30 kN placed 3.0 m from the right-hand end. The joist has a depth of 150 mm and the maximum tensile strength that it is allowed to withstand is 12 MPa. a) Calculate the bending moment 1.0 m and 2.0 m...
  37. I

    What is the neutral axis for a rectangular beam with depth 'b'?

    Hello friends, a question about the engineers bending equation, M/I = E/R = (sigma)/y so take for example a beam with a rectangular cross section with depth 'b'. Will y then equal b/2 ? As y is measured from the neutral axis? Thank you in advance for your time, Claudius
  38. S

    Strong axis bending question

    Homework Statement there's a composite beam that's wood on top (150mm along the x axis, 250 along the y) and a little piece of steel along the bottom (150mm along the x, only 10 along the y). Ew is 10,000MPa, Es is 200,000MPa (these are the elastic moduluseseses). the beam is to be analyzed...
  39. C

    Why Does Light Bend Away From the Sun?

    I am reading God's Equation by Amir Aczel and he talks a lot about the early observations of eclipses which showed a displacement of the starlight around the sun, because space is curved around massive objects. But why does light bend away from the sun? If it's being affected by gravity...
  40. D

    Calculate Reaction Forces at B & D: Beam Bending Homework

    Homework Statement Calculate the reaction forces at B and D See attached jpeg. The Attempt at a Solution sum of vertical forces By + Dy = 7 + (9*5) Do I then solve for the moment about D or A or B? for moment about D i have: -Dy -7 -(9*5)+9By+(12*2)=0 is this correct, please explain to...
  41. D

    How to Calculate the Maximum Bending Moment of a Simply Supported Beam with UDL?

    A simply supported beam is loaded with a uniformly distributed load (UDL) W=40 kN/m from C to D. The maximum Bending Moment value occurs at the mid-length of the beam, i.e. 3.5 m from the left hand end A. What is the value of the maximum bending moment? Give your answer in kNm, with 1 decimal place.
  42. R

    Calculating Bending Moments Along a Beam

    Homework Statement Calculate bending monents at 1m intervals along the beam Homework Equations The Attempt at a Solution I'm not sure where to start really? I think this is nearly there? Ma = 0 M1 = -5 x 1 M2 = (-5 x 2) + 26.7 M3 = (-5 x 3) + 26.7 - 10 M4 = (-5 x 4) +...
  43. ?

    Moments and Bending Moments

    Hello, I have a small question about moments and bending moments. So, if I have a beam with a loading given by q (N/m) which is given as a function of x then what do these calculations get me? \int xq(x) dx \int (\int q(x) dx) dx The first integral gives me the moment about a point because I...
  44. M

    Calculate Max Bending Moment for 10m Beam ABCD

    Homework Statement The beam ABCD in question is 10m long with supports at A and C. At B there is a 50KN point load and another 20Kn point load at D. The is a uniform load between A and c of 30KN/m. A is 8m from C, A is also 2m from b and d is 2m from c. I need to find the max bending...
  45. F

    Understanding Spacetime Bending & Gravity Effects

    I'm having some troubles understanding how spacetime actually looks and what causes gravity and unifying the idea with the general relativity consequences, like light bending. So, if spacetime is bent by massive objects like in this picture: HOW does the light bend outwards that massive...
  46. I

    Optimizing Conduit Bending for Wire Pulling Efficiency

    Pertaining to conduit bending and ease to pull wire, would it be easier through one 90 degree bend of a set radius, or would it be easier to pull through two 45 degree bends using the same radius. The 45's could be any distance apart from each other, I don't think it would matter too much (am I...
  47. A

    Finding Maximum Bending Moment of a Beam – Help Needed!

    hi i want to find out the bending moment of a beam at a distance from one end is given by M=1/2\omega (lx-x^2) where \omegaand l are constant. how do we find maximum value and why its maximum value i would realli apreciate it if someone would help me
  48. S

    Calculating Fixed End Moments with Uneven Beam Heights?

    Ok, so I have a problem as follows: A beam is simply supported at joints A, B, C D and E. there is a UDL acting on the BC member The member is 6m long with a UDL of 60kn/m However the tricky part is that this member is 1.2 times higher than the height of the members AB, CD, and DE. So BC =...
  49. A

    Bending Wires and Magnetic Fields?

    Homework Statement see attached. this question is from a test that doesn't allow any calculators and usually makes students solve the problem in 1 minute max. Homework Equations perhaps biot savart is to be used? but I doubt that can be done in the time limit... The Attempt at a...
  50. S

    Maximum bending moment in aluminium alloy beam

    I have three questions and need to calculate the magnitude of the maximum bending moment 1) A 4 m long aluminium alloy beam, simply supported at its ends, carries a central concentrated load of 2 kN. The T-cross-section of the beam (see Figure A2) consists of a rectangular flange and web...
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