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. J

    Uniformly distributed load - Max bending moment help

    Homework Statement I have to work out the reactions at A & D. Sketch the shear force diagram for the beam and sketch the bending moment diagram. i have worked out the reactions at A=56kN and D=34kN. I have done the SFD. I am just struggling doing the bending moment diagram and don't know how...
  2. 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...
  3. Fallen-S36

    Bending the Rules (Gamma ray lenses)

    http://news.sciencemag.org/sites/default/files/styles/thumb_article_l/public/article_images/sn-gammarays.jpg?itok=vYTMw8My Researchers at Institut Laue–Langevin have found a way to bend gamma rays. Gamma ray lenses, which theory had suggested were impossible, could be made from heavy elements...
  4. A

    Help with Bending Moment Diagram for Structure

    Homework Statement Hi I need help with drawing a bending moment diagram for this structure. All joints are rigid and it's fixed to the ground. I'm really struggling with this. I initially started with the horizontal beam (statically indeterminate) and found that the moments at the ends were...
  5. 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" !
  6. 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...
  7. 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...
  8. M

    Need to find the length and deflection of bending element

    Hi, I have a task and don't know the good solution. (I add the picture of my task.) I need to find the right length and deflection and to check if the results didn't exceed the allowable stress. I know the value of "q" (force). Also I could choose myself the lenght, but I need to check, if my...
  9. N

    Bending moment and shear force for screw

    Can someone help me with determining the free body force diagram, and hopefully I can go on from there. Homework Equations M = F.dI found T = 500N The answers are shear force = -62.5N , Moment = 64.4 Nm , Tension = 500N
  10. R

    Bending and welding Aluminium 2mm sections

    Hi I am planning to make a light weight camera mount for my RC multicopter (drone). Issue is due to irregular shape of the camera, need for the mount to be light weight, and setting up a small angle of inclination (5-10 degrees) the only solution I have come up with is to use light weight thin...
  11. R

    Einstein theory on bending of space

    According to Einstein's theory it is the bending of space that keeps the Earth moving on its orbit around the sun and not any invisible force. Why they still teach gravitational force in school ?
  12. T

    Space Bending: Questions & Answers

    There is something that confuses me when I read about space bending. For something to bend it needs to be in space, because otherwise bending does not exist. For example, it makes no sense to talk about the bending of bytes because bytes are not really in space. So how come that space can...
  13. Keystone

    Bending Light? – Questions & Answers

    Hi , so , i am not asking this question for invisibility or anything like that, but i do have a few questions. First off, i know that photons have no charge, but is there any way that electro magnetic pulses can effect their path when the copper coils that make the electro magnet are at very...
  14. M

    What did I do wrong? Bending moments & deflection question

    Homework Statement Problem shown as image jan2010 Q5.jpg Q5. a) Homework Equations Also shown in image The Attempt at a Solution Made a cut between A and the z-line, so ∑M = 0 = M - wx(x/2) = M - (wx2)/2 ⇒ M = (wx2)/2 and d2y/dx2 = -M/EI ∴ d2y/dx2 = - (wx2)/2EI So dy/dx = ∫ d2y/dx2 dx =...
  15. Y

    Band bending versus band sloping

    I'm trying to reconcile how a built-in potential can form in a semiconductor heterojunction in which there is a significant band cliff to majority carrier diffusion from both sides of the junction i.e. there is a cliff which should block hole diffusion from the p-type as well as a cliff which...
  16. A

    Finding Pure Bending Moment for Simply Supported Beam

    i am trying to find the pure bending moment of this beam 1. Homework Statement simply supported solid beam 3m long W=100mm D=200mm with a UDL of 2tonnes/m and a point load in the centre of 200N Homework Equations is the pure bending moment at the peak of the bending moment diagram i have...
  17. K

    Shape of a Bending Beam with P Applied at the Axis of Symmetry

    Homework Statement A beam (e.g. a steel liner) of a length L is bent between two supports, as shown in fig (a). According to the Euler column, the shape is a half period of a sine. Now, a force P is applied at the axis of symmetry - fig (b). What is the shape of the liner? y=f(x) Instead of the...
  18. A

    Allowable stress in my project

    I'm doing a little project which came to a stop. I calculated expected material stress to be ~10 MPa. (bending) I know that my material (AlMgSi0,5) should carry well that stress, however I'm interested in max allowable stress for this material...
  19. T

    Tensile Strength & Bending Stress of Metal Sheet

    Dear Friends, Merry Christmas to All. I am pleased to join this forum of Physics Experts. Please advise what is difference between tensile Strength and Bending Stress of Metal Sheets (Generally below 3.00mm and lighter). I very often encounter with cracking of steel sheets while bending in...
  20. A

    What Equations Are Needed for Calculating Beam Stress and Curvature?

    Help needed In my course paperwork I can't seem to find the relevant equations needed to complete the following in if someone could help point me in the right direction of equations needed I would be very grateful 1. Homework Statement A rectangular hollow beam length of 3m is simply...
  21. D

    Bending of Light: Newton vs Einstein

    Okay so according to https://briankoberlein.com/2014/08/01/bend-like-Newton/ link https://briankoberlein.com/2014/08/01/bend-like-Newton/ "The catch is that the amount of bending predicted by Newton’s model is half of what Einstein’s model predicted." (This is right after the changing diagram...
  22. 1350-F

    Brittle Materials: Bending Yield Strength

    It seems to me that the ultimate strength of a brittle material can be easily determined by a bending test, but what about the yield? In the brittle regime, I can see how you couldn't, since the sample would fail before it would flow significantly. However, brittle materials can be made to flow...
  23. T

    Bending Stress in Top of T-Beam

    Homework Statement T-Beam is Steel with E=200GPa Find Max bending stress MC/I (right side where no glue)[/B] 80KG Load at Point "A" shown on the Top view Blue stuff is glue, the right side has no Glue, so its just empty space 2. The attempt at a solution I = BH^3/12 , where B = 0.04m H =...
  24. P

    Bending disturbances in axisymmetrically loaded spherical

    Can anyone please give an example of the use of bending disturbances in axisymmetrically loaded spherical shell using Geckeler approximation
  25. R

    Band bending, depletion layer thickness, density of occupie

    Homework Statement Consider an n-type Si (Eg =1.1eV, ED=EC, εr=11.8) with a bulk doping density ND=1×1017cm-3, a density of acceptor type surface state 1×1014 cm-2 and these states are at the middle of the band gap. Evaluate the amount of: a) band bending b)depletion layer thickness c) density...
  26. M

    Shear Force and Bending Moment

    Hi everyone here is the question I'm having trouble with. included is my attempt and the question. 1. The Reactions at A (Assuming the boom weight is negligible) 2. The shear force and bending moment along the boom length and indicate the point of maximum bending moment. 3. The maimum bending...
  27. K

    Determining Young's Modulus by Bending a Piece of Wood

    There is an experiment to determine the Young's Modulus of the wood which involves bending it. The equation used to calculate it is like this E=WX3/4ZDY3 Where D=amount of bending W=force (N) which causes the bending Z=width of the wood Y=thickness of the wood X=horizontal distance between the...
  28. S

    Analytical solution for bending stiffness of tapered tube

    How to derive the formula to find the bending stiffness of an isotropic tapered tube which is cantilevered with a point load applied at the free end?
  29. K

    Question related to Bending Stress and Shear Stress of a I shape beam

    1. Homework Statement The beam ABCD with the cross section has pin connections at B and C and is subjected to a uniformly distributed load w. If the allowable bending stress is 150MPa and the allowable shear stress is 80 Mpa. ( Hint : the horizontal reaction forces at A and D are both zero)...
  30. J

    Piezoelectric Actuator Cantilever Beam bending

    I do not have much knowledge in piezoelectric, but all the piezoelectric I've read up on seems to only achieve maximum displacement in measurement values of microns. Is it even possible for some piezoelectric actuator to bend a 10 meter long cantilever beam up to 1 meter at its maximum...
  31. R

    Can I Calculate Shear Force and Bending Moment for Partially Loaded Beams?

    Hi, I am designing a beam to replace a load bearing wall. I have produced 2 separate UDL diagrams which, one for floor load and one for wall load. I am trying to find shear force and bending moment as in one for the total of the two diagrams. I know how to do it if the loads are spread...
  32. O

    How does band bending occur in condensed matter physics?

    I'm trained in Condensed Matter Physics, and I'm trying to learn EE. The concept of band bending always baffled me a bit. Here's why: The band edge bloch states are delocalized over the whole of the crystal, and have fixed given eigenvalues. How can this eigenvalue change over the length of the...
  33. M

    Flexural Bending Test: Structural Integrity of Pre-Preg Panel

    Hi! Need help on following question: Does a flexural bending test suffice for determining the structural integrity of a pre-preg honeycomb sandwhich panel with carbon phenolic face sheets and aluminium core? Any help will be deeply appreciated
  34. G

    Calculating Bending Stress: Theory & Answer (3.84 x 10^6Nm-2)

    How do we get the answer 3.84 x 10^6Nm-2 When I use my calculator I get 3.84 x 10^-4. See attached PDF. I guess I'm making a pretty basic error but I don't know what it is. Thanks Gavin
  35. R

    Beam problem finding max bending stress

    Alright so I drew it out like did the reactions and everything then I realized I need to include the diameter of the beam. How do I find the max bending stress while using the diameter of the beam? All I need to know is what exactly I do differently compared to drawing the bending moment...
  36. ajayguhan

    Linearly varying force and bending moment problem.

    I have attached both the question and my attempt at solution. My problem is reducing the equation further to get the value of a/L
  37. avito009

    Bending of Light due to Gravity

    Why does light bend due to gravity? I thought hard, read a lot and I found 3 reasons I can give as the answer. But first let me tell you what Newton said. According to Newton light (Photons) is massless so light can't bend due to gravity because only things with mass can be affected by...
  38. R

    Water bending with static electricity

    thinking about growing cacti in a tropical climate...could i perhaps build a charged scaffold around them to keep most of the rainwater away? if this is possible i might lose the walls i tend to stay in as well by upscaling it.
  39. M

    What is the formula for calculating steel rod bending in a mouse trap?

    Sorry this isn't really intro to physics, it's high school physics... I'm investigating the force vs angle of a mouse trap and I need to talk about the uncertainties one thing is that the lever (hammer/arm/part that hits the mouse) bends. So the angle isn't very accurate. What formula do I...
  40. B

    Bending moments on a rotating body

    Homework Statement A body (let's call it a rod for simplicity) is in frictionless space, and is composed of 4 smaller sub-rods fused (cannot break) end to end. Each sub-rod has a unique mass (m1, m2, m3 and m4) and length (l1, l2, l3, and l4), but they all have the same diameter d. A force...
  41. P

    Problem with values for a bending moment diagram

    Homework Statement I have a 5m long simply supported beam, with supports at points 0m and 5m. There's a UDL of 10kNm^-1 from 0m to 4m. It has downward forces acting at 2m (10kN) & 4m (15kN). I need to sketch a bending moment diagram to determine the position & value of the max bending...
  42. J

    Increasing bending stiffness of a steel tube

    Hello, Looking for some advice on increasing bending stiffness of a mild steel 1" x 0.065" round tube. This is for a motorcycle frame and clearance is an issue. There is a fuel tank above and the engine below this top tube (two running parallel) that I wanted to reinforce against bending...
  43. I

    Calculating Bending & Shear Moment: Homework Statement

    Homework Statement (a) Calculate the maximum bending moment (b) Calculate the maximum stress in the beam (c) At the point of maximum stress sketch a graph of the stress distribution through the thickness of the beam, indicating which are tensile and compressive stresses. (d) Determine the...
  44. N

    Bending Vectors: Can We Make Curvy Ones?

    Can we make curvy vectors? Or to put it another way: Instead of one straight direction, can the direction be round(or something like that)? Thanks
  45. L

    Beam bending of an angled flat plate

    Hello everyone, I am wondering how to properly go about calculating the stresses caused by bending on an angled flat plate. Two approaches seem valid but they give much different results: -Calculate the new area moments of inertia for the angled flat plate (new Ixx, ymax)...
  46. O

    Bending Light - Exploring How & Why Laser Light Moves in Springs

    Hello. I saw this experiment: The light from laser is bending in small hole and moving in spring. I don't understand why. Please, can you tell me why? Why does spring moving in spring, not in air? It will happens in each spring? Why it occurs? Thank you very much
  47. C

    Light bending with electric or magnetic field?

    If photons are oscillating electric and magnetic fields, then we should be able to deflect photons trajectories by external electric or magnetic field, right? Are there any experiments, either successful or unsuccessful, that attempted to bend the light in some such way?
  48. B

    Bending Moment of a Cantilever Beam

    This is a problem from Michael Lindeburg's FE Review Manual. It is in Chapter 20, Number 11 if you have the book. PROBLEM: There is a picture of a cantilever 2 m in length attached to a wall. There is a force applied at a 30 degree angle from the horizontal at the free end of the beam...
  49. H

    Help with Bending of a Plate with unique boundary conditions

    Hi, Can anybody help me withg the following problem: A rectangular plate with points starting from top left corner and going clockwise:: A B C D. Sides CD and DA are simply supported, and a point force F is applied anywhere on the surface. I am looking for the bending stress distribution...
  50. U

    Discovering the Shape of a Bending Plate: Mathematical Proof in 2D Statics

    This is sort of statics, but this came up in my physics class before. You have a plate, supported only in the middle by a simple support. So, this beam is balanced on the support, and is bending under it's own weight. What shape does the beam take? I was thinking either a inverted parabola or...
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