What is Vibration: Definition and 471 Discussions

Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin vibrationem ("shaking, brandishing"). The oscillations may be periodic, such as the motion of a pendulum—or random, such as the movement of a tire on a gravel road.
Vibration can be desirable: for example, the motion of a tuning fork, the reed in a woodwind instrument or harmonica, a mobile phone, or the cone of a loudspeaker.
In many cases, however, vibration is undesirable, wasting energy and creating unwanted sound. For example, the vibrational motions of engines, electric motors, or any mechanical device in operation are typically unwanted. Such vibrations could be caused by imbalances in the rotating parts, uneven friction, or the meshing of gear teeth. Careful designs usually minimize unwanted vibrations.
The studies of sound and vibration are closely related. Sound, or pressure waves, are generated by vibrating structures (e.g. vocal cords); these pressure waves can also induce the vibration of structures (e.g. ear drum). Hence, attempts to reduce noise are often related to issues of vibration.

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  1. Reno Nza

    Differential equation for a vibration problem

    Homework Statement The data given was the acceleration of the component over time, as below: time | Acceleration (m/s²) 0 | 0 0,2 |3,61 0,4 |4,5 0,6 |5,4 0,8 |7,508 1 |12 - The Rigidity constat is 12600000 [N/m] (for the spring) The damping constant is 6500 [N/m] (for the damp)...
  2. r_prieto5

    Sprocket diameter, chain link pressure, transverse vibration

    Homework Statement Power=P, rotation speed n1, rotation speed n2, chain center distance c, life = Lh All I need for this one is the formula for sprocket diameter. I have found calculators (https://www.rbracing-rsr.com/calcsprocketdiam.html) but no reference to the formula. Chain pitch and...
  3. M

    What is this and where can I find a replacement

    The square seat (?) for the accelerometer has started to fall apart and I need to find a replacement for it. If this helps, the accelerometers are placed equidistant apart from each other, and the tester hits it - the cantilever beam - with a mallet to simulate vibration. Please refer to the...
  4. NTibbs

    2-DOF problem with unknown stiffness and velocity

    Homework Statement I have a 2-DOF system, whereby I have one body that is grounded by a spring (body A), and a second body (body B) attached to the first by a spring and a viscous damper. For body A, I know the velocity and amplitude (before body B is added). I think I also have the stiffness...
  5. A

    Vibration of double pendulum

    Homework Statement m = 1 kg, l = 1 m, theta 1 and 2 are small I want to work out the natural frequencies (2) of this 2 DOF system through taking torques about the fixed point on the ceiling. I've done it using numerous fixed points and just cannot get the right answer.[/B] Homework...
  6. DavidReishi

    B Would time slow down tied to a nuclear-powered oscillator?

    I've always wondered this. Let's say we're not limited by the type of vibration, e.g. if choppy vibration doesn't constitute continuous movement, then some sort of oscillating vibration.
  7. M

    Vibration absorber for a quadcopter?

    Homework Statement I am supposed to examine the effectiveness of a vibration absorber design for a quad copter. Attached is a picture of the quad copter and the design; basically each of the spring dampers would be attached to an arm of the copter. In the case of a single quad copter arm, what...
  8. N

    Question about free damped vibration in an SD

    Homework Statement "If a horizontal force of F = 299kN is applied to the right at the girder level by a hydraulic jack and then the force is removed suddenly, find the equation of motion of the girder. Consider 5% critical damping. Find the displacement and velocity of the girder at 0.2 seconds...
  9. KarminValso1724

    B How does the vibration of a quantum string translate to a "particle's" mass?

    According to string theory, all elementary particles are really 1 dimensional vibrating strings and the frequency that the strings are vibrating create different particles with different masses and other properties. But what I seem to not be able to find an answer to is how the vibrational state...
  10. H

    Need Help Finding Cheap Vibration Testing Equipment

    Hi PF, I hope I'm doing this right, first post. I need help with a research project for the effect of the ambient vibration frequency at resonance for a piezoelectric energy harvester (It's well documented, I know, but I have to do an experiment with it anyways). Anyways, I noticed that...
  11. P

    Passive vibration suppression using piezoelectric elements?

    I am looking at one idea to passive vibration supression that involves "a resistive shunt to a piezoelectric material" but I can not find a lot of info outside of papers that I would have to pay for. does anyone know and can explain some detail about this method?
  12. Jeng Ho

    How to calculate the vibration from motor

    Good evening, I have a question about calculation vibration of produced from a motor. The engine provide is 2 stroke engine, 1.3 horsepower, 3.2 kg in mass, bore size 34mm, stroke 28 mm and with maximum rotation per minute is 10500 rpm. Can I calculate the vibration produced by engine or not...
  13. C

    Frequency of Vibration of a water tank

    Homework Statement Assume that there is a tank on a 200 ft pedestal type support. When full the tank and contents have a weight of 50,000 lbs and it is never drained to a point where the tank and contents have a weight less than 20,000 lbs. Assume the pedestal weight is negligible compared to...
  14. T

    Rotation and vibration of 2 particle spring system

    Homework Statement Homework EquationsThe Attempt at a Solution Is it possible to solve this problem without using Hamiltonian Mechanics (just by Newtonian). My instructor expects use to solve this problem without any knowledge of any advanced classical mechanics. I tried to solve this...
  15. Vivek Sagar

    How to perform forced vibration analysis cal using ansys

    Hi, My problem is that I have a flat rectangular plate acted by in-plane concentrated force. I want to do the forced modal analysis for 5 modes using ansys for this plate. Can anyone tell me how to do this. Regards, Sagar
  16. C

    Find the frequency of the cylinder's vertical vibration

    Homework Statement Homework Equations w = √k/m w = 2π/P ƒ = 1/P The Attempt at a Solution I feel like I'm so close to the answer, I think it has something to do with the fact that there's a spring and pulley in the system that is throwing my answer off. I have √k/m = 2π/P So, P =...
  17. T

    How to reduce vibration of a fixed beam?

    If I want to reduce the vibration of a beam fixed at one end, under a distributed load, does anyone know what this would involve? In the textbook, there is the idea of having a second system consisting of a mass-spring combination to reduce the vibration of the primary system. But I can't find...
  18. D

    Landau's Books - Vibration - flexible string

    Hello everyone, I would like to know if i can find in any of the Landau's books a chapter ,part concerning the flexible string ( differential equation , normal modes , stading waves ) ? I have tried to see but i can't find anything . There is a chapter concerning sound waves in a medium ( volume...
  19. Z

    What distinguishes one mode of vibration from another?

    This is a really silly/very basic question but I'm having trouble finding a clear, concise definition of a "mode of vibration"; assuming the same object that is vibrating is being discussed each time, are the only things characterizing a mode of vibration the waveform, the frequency of the mode...
  20. T

    Use of diagonal matrices in vibration analysis?

    why are diagonal matrices and eigen vectors useful in vibrations analysis?
  21. W

    Is sound a renewable energy or non-renewable energy?

    I've been searching the web for this answer and can't seem to find it anywhere. Can anyone help me? Is sound a renewable energy or non-renewable energy?
  22. A

    Solving boundary conditions for vibrating beam

    Hi there, I'm solving the equation for the transverse vibrations of a Euler-Bernoulli beam fixed at both ends and subject to axial loading. It's a similar problem to that described by Rao on page 355 of his book "Vibration of Continuous Systems" (Google books link), except the example he uses...
  23. E

    Good Vibration Stability Mapping Software?

    Hello Physics Forum patrons! I am currently in search for some software and maybe hardware to analyze and map vibration/stability for rotating cutting tools (CNC milling). Being primarily a machine programmer and product designer, I have a very minimal understanding of vibration from a physics...
  24. R

    Vibration proof hinge and lock

    Hi All. I am stuck in a problem. Please check the image attached. It's part of a foldable mechanism of a quad copter arm. The red part is fixed to the body, the grey part is fixed to arms. The transparent part is a threaded collar/sleeve. The yellow part is a stopper. The hinge is a connecting...
  25. F

    Period of Vibration of Torsion Pendulum

    Homework Statement Given the period (T) and the moment of inertia (I), find the Torsion constant (K) T= 1.32s I= 0.0383 kgm^2 Homework Equations The Attempt at a Solution The answer is K=0.8678, I'm not really sure how to get the answer, but I think it has to do with the units.
  26. muharifiandi

    Frequency response of Torsional Vibration

    Hello engineers! I have a project to measure/ obtain natural frequency of torsional vibration. Below is the detail: 1. Object measurement: Two rotor attached to one shaft and the shaft is supported by two bearing. The shaft is connected to a motor. I give the scheme below. 2. Equipment: two...
  27. Observeraren

    Vibrations in a glass with water.

    So I just poured water in a glass to clench my thirst. Hit the 2/3 empty glass with a pen and a high frequency started resonating for a brief moment, which I percepted as sound. When I tilted the glass the tilt resulted in change of frequency. When the glass was empty there was no change in...
  28. S

    Plate Buckling Deflection Function for Rayleigh Ritz Method

    G'Day Everybody, I am computing buckling of a rectangular(edges: a*b) specially orthotropic composite plate. The boundary conditions are clamped-clamped at the opposing loaded edges and the other two edges are free (also known as CFCF). After having the boundary conditions and the governing...
  29. J

    Calculating/simulating effect of mass changes in a gyroscope

    Can anybody suggest a free SW to simulate the behavior of a gyroscope upon adding/removing a mass in various places with respect its rotational axis and/or baricenter? It looks like it's quite complex to manually calculate or just "imagine" it. A gyro standing on a floor does behave in a...
  30. Ronie Bayron

    What Is the Speed of Sound and Vibration in Solids?

    Say, I have 10 Km (1m dia.) exposed pipeline under construction phase. 9 Km of the pipe line was already done. Its so happen that at the next pipe length installation, the plane operator mishandled the pipe and it collided at the end where connection should be made, big time that the magnitude...
  31. W

    Air time/displacement calculator for floor vibration

    This question might be out of the scope of this forum but, Assume an object (lets say cube) rests on an even floor that at all points is vibrating vertically at the same frequency at all times. (a platform going up and down) The floor is vibrating vertically at a FIXED displacement. How can i...
  32. F

    Are the vibration modes at the lattice centre odd or even?

    Homework Statement Good morning. I am currently doing an solid state problem; in this part, I have to tell if these vibration modes are odd or even. I am working at the lattice centre. The modes are these http://postimg.org/image/8nmv7ickz/. Homework Equations None The Attempt at a Solution...
  33. F

    Studying vibration modes of ice X

    Good afternoon. I am doing an study on ice X, a material with this structure http://postimg.org/image/nub4if9kb/ I want to know why in the centre of the brioullin zone the hidrogen atoms must remain at rest on an even mode. My reference book is Charles Kittle's, but there is no discussion about...
  34. R

    Equation linking superstring vibration with mass?

    Is there an existing equation, or set of equations, that directly links the specific vibration of a superstring filament with the resultant particle mass? A brief explanation of any mathematics would be helpful. Thank you.
  35. A

    Uniformity of thermal vibrations

    Hello, I have a question on the nature of vibrations due to thermal energy. Earlier today I read this article which talked about cooling a glass string to near absolute zero using feedback from a high precision sensor. http://phys.org/news/2015-08-smallest-vibration.html what I understood from...
  36. H

    Vibration Based Energy Harvesting

    So, personally, I'm really excited about having wireless energy harvesting. I was looking up articles on piezoelectrics, since that seems to be the leading thing these days, and I encountered an article that designed a MEMS circuit (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3958224/). It's...
  37. B

    Mathematical modeling of the deflection of a rod

    A rod is radially mounted on a motor shaft and provided with a flat end plate. By turning movement, the end plate will touch a pointed object, and the angle turned is measured.By the torque of the motor during acceleration and deceleration, a vibration and deflection happens on the rod. The...
  38. Spacexplorer

    Understanding How Dampers and Springs Work in Car Suspension Systems

    Hi guys. It could be an easy question but I started at the deepest. I wonder how it works like a car suspension system. How does damper work with spring? What is the difference between forced-nonforced systems? Why do we calculate frequency of spring? What does it provide us? What is the point...
  39. B

    No vibration spectrum for homonuclear diatomic molecules?

    Supposed to be because they have a zero dipole moment... Dipole moment is variously described using neutral systems of pairs of opposite charge, or single items with charge, but I am finding no explanations of same charge pairs I understand.. Wiki states: "To show a vibrational spectrum, a...
  40. K

    Vibration Vs Oscillation Vs Wave: What's the difference?

    Hi all, I am confused about the terms: Vibration, oscillation and waves. Is vibration and oscillation same or are they different? My understanding is vibration is associated with flexible/deformable bodies and oscillation for rigid bodies. Waves not really having an idea! Any examples of...
  41. Q

    Nonlinear Mass Spring Damper with Euler Bernoulli Beam

    I'm trying to find a solution to a system in which a clamped free Euler-Bernoulli Beam system rests on top of a mass-spring-damper system. The MSD system has nonlinearities in both the spring and the damper and is of the form: I have extended the nonlinear restoring force to its 3rd term and...
  42. SSGD

    How Can Vibration Damping Materials Reduce Machine Noise?

    I am trying to reduce the noise created from a machine that makes contact (impact) with a thin plate. I just don't have anyone to bounce ideas off of. I can change the support geometry to whatever I want as long as it will with stand a static load and the impact. I can handle this, but the...
  43. G

    Vibration analysis - thin circular plate

    I'm moving on to a new area of focus at work and have found myself analysing a vibration issue. I've had the basics a BSME gets you at an accredited university (20 yrs ago), but am rusty to say the least. I'm looking for guidance on good reading materials to knock the rust off. My problem is...
  44. K

    Problem with Vibration and Waves AP French?

    Hi All, Kindly see the attached Pictures. I think COB is not 90 - δ/2 But COB is 90-δ Can someone confirm. Thanks.
  45. O

    How to calculate the vibration modes of the beam?

    Hi, I´ve tried to calculate the vibration modes of beam in the space, without gravity or any other force. The forumle of the beam is this one: Cos(λL)*Cosh(λL)=1 from which I´ve calculate the roots and the resonance. I´ve found a programme for Matlab that calculates the vibrations modes if...
  46. A

    Where is the Force Transferred in a Lathe with an Unbalanced Load?

    If I mount an unbalanced piece of wood on my lathe, it causes vibration. i.e. I'm spinning an offset mass at a high rate of speed. If I add weight to the base of the lathe (e.g. sand bags, concrete blocks, bolting it to the floor), I can stop the vibration. My question is, where is the force...
  47. A

    Vibration problem: natural frequency=resonance?

    Hi... I am leanring some knowledge about vibration. For a given vibaraiton system, for example, cantilever beam, we can perform modal anlaysis and found five natural frequency of 3, 6, 8, 10 and 20 Hz (just made up) and five corresponding vibration modes. after that we give a harmonic force on...
  48. B

    ANSYS: What are vibrating feeder's boundary conditions?

    I have created such vibrating feeder model on SW but on ANSYS I'm only analyzing the frame. 1)How do I set up boundary conditions, I think I need elastic supports? 2)In modal analysis I have elastic, fixed supports, remote displacement - which should I use and in what directions? 3)Do I perform...
  49. S

    Particle Vibration, Velocity, Gravity, Force

    If my assumption is correct, Particles are vibrating is some repetitive way which can be charted as a sine wave on a graph. If you start at 0, go up, then down below 0 then up to 0 again you have completed a "cycle." The rate of cycles is known as Frequency. Does Velocity and/or Gravity affect...
  50. Kerim Erol

    I-beam section free vibration on ansys

    Hello. I have to do an analysis for my thesis. It's about "free vibration of I section beam, composite material". I searched it on the internet but i did not find an appropriate thing. I can do the analysis about it but i must compare the results. So, is there anybody help me about it?
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