What is Natural frequency: Definition and 130 Discussions

Natural frequency, also known as eigenfrequency, is the frequency at which a system tends to oscillate in the absence of any driving or damping force.The motion pattern of a system oscillating at its natural frequency is called the normal mode (if all parts of the system move sinusoidally with that same frequency).
If the oscillating system is driven by an external force at the frequency at which the amplitude of its motion is greatest (close to a natural frequency of the system), this frequency is called resonant frequency.

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  1. Link

    Mass of cantilever vibrating at natural frequency

    Homework Statement Find mass of vibrating steel cantilever. It is fixed at one end and got a mass on the other (free) end. Find the mass required when it is vibrating at w(natural) = 1800 rev/min. Lenght: 50mm width: 7mm Thickness: 1mm Homework Equations w = sqrt(k/m) The...
  2. L

    Multiples of natural frequency?

    Multiples of natural frequency?? Hi all! I am a little confused. Why will an object not resonate with multiples of its natural frequency? I think due to the reason that through its multiples, it will not return (even if temporarily) to its natural state...am I mistaken?? Thanks in advance...
  3. V

    Forced oscillations vs Natural frequency

    What happens if the frequency of the forced oscillation is Pi / 2 radians out of phase of the natural frequency of the spring mass system? I guess this makes the amplitude of the spring mass system to oscillate at a maximum amplitude.. Am I correct? Thanks in advanced..
  4. S

    Resonant frequency vs Natural frequency

    I happened to sit in a presentation where the presenter displayed 2 separate values for resonant frequency and natural frequency. It was my understanding that the both are same and now I am in doubt. Please explain - if there is and you know - the difference between resonant frequency and...
  5. S

    Natural frequency determination

    I have estimated some transfer frequency functions of complex mechanical suspension. It is shown the gains reach a very high value at a 0.8Hz. How could i know if the 0.8Hz isthe suspension natural frequency?
  6. T

    Resonance and natural frequency

    Homework Statement Ok, this is not homework, just something that's been bugging me and my tutor is unavailable(as usual) to help me. Why does increasing the mass of a system lower its natural frequency, like adding a concrete block to a washing machine. Come to think of it, I'm not even too...
  7. K

    Is the natural frequency the highest frequency?

    I have a theoretical question. Does a structure's natural frequency have anything to do with the highest frequency of which it can vibrate? Or can the structure vibrate in any multiple of the natural frequency (until it brakes...)?
  8. G

    Natural frequency resonance help

    I have just started to study resonance and I don't quite understand what it is. My textbook says: "All objects vibrate with a characteristic "natural frequency". When an object is forced to vibrate at its natural frequency, the amplitude of its vibration can grow very large. This effect is...
  9. T

    Damping , resonance and natural frequency?

    When a forced oscillation is damped, it is true that the frequency at which resonance occurs decreases right? so does this mean that the natural frequency has decreased too or does it only mean that resonance does not occur at natural frequency when being damped?
  10. J

    Natural Frequency Using Rayleighs Energy Method

    Hi everybody! I'm a complete newbie here, but I was hoping somebody might be able to help me out with understanding Rayleighs Energy Method and how to calculate the static deflections/natural frequencies. I am basically looking for the first and second modes/natural frequencies of a 2 mass...
  11. H

    Natural Frequency Of Space Frame & Motorcycle Frame

    Hi How do you calculate the natural frequency and vibrational response of a space frame and what is its damping characteristic? What are all the aspects to take into considerations and how do you analyse failure due to vibration? Thanx
  12. B

    Natural FrequencyWhat does the natural frequency of an object depend on?

    What does the natural frequency of an object depend on? Whenever I try to look this up, I usually read that the natural frequency depends on "intrinsic" properties or a "variety" of factors. Is the natural frequency independent for each object/is there any universal factor the natural...
  13. S

    Why is the natural frequency of a cantilever beam higher than a spiral spring?

    Hi Natural frequency of spring is fn = 1/(2*pi) * sqrt(k/m), where k = spring constant and m is the mass. Ok, so I have a spiral spring which means that spring is coiled couple of times. Its spring constant is (according to Hartog's Mech. Vibrations), k = E*I/l, E=Elastic Modulus, I = Inertia...
  14. M

    Natural Frequency of Stepped Shaft

    Hi guys, I need to find the natural frequencies of a series of pressure rakes. We have a numerical model, but I'd like to confirm with a hand calculation. I would like to model the pressure rakes as a cantilevered beam with varying cross section (i.e. as each tube "stops" the beam decreases in...
  15. S

    Natural Frequency of Cantilevered Coil

    I would like to calculate the natural frequency of a cantilevered spiral coil. So instead of having a standard beam which is straight, I have a beam which has one end fixed to an axle and the beam is spiralled several times around the axle. The end of the beam comes out of the spiral and runs...
  16. A

    Finding the natural frequency of a set of data

    Homework Statement Hi all, I'm having an issue with a homework problem. I'm taking a vibrations class and in our lab we had a cantilever beam with a mass on the end. There is an accelerometer on the beam and we used an impulse hammer to hit the beam. We had software that recorded all the...
  17. A

    What gives rise to natural frequency?

    What gives rise to natural frequency? Resonance is when an oscillating force has a frequency that matches the natural frequency of a system... but what gives rise to the natural frequency of the system?
  18. C

    Modes of vibration, natural frequency

    Hi.. I have a question about natural fvibration. Every object has natural frequency and modes of vibration. Let us consider a simple cantilever beam for our discussion. and Let's say its first 4 modes of vibration are at 3, 6, 10 and 20 kHz respectively. (I made up these frequency values)...
  19. V

    Natural Frequency and wavelength

    Homework Statement The portion of a piano string between the bridge and upper end of the finger board is 0.50 meters long. The string when plucked sounds a note of 440Hz- the first harmonic. a. where must the violinist put a finder to pay a C note- 528Hz b Without returning, is it possible...
  20. P

    Natural frequency of a spring(self-weight only)

    natural frequency of a spring(self-weight only) giving the length,mass, and spring constant of a spring...how do you find the resonance frequency..having been thinking about this question for so long, does anyone know how to approach this question...
  21. B

    Natural frequency calculated theorectically and experimentally

    Homework Statement I was given a spring mass system and asked to calculate the natural frequency by theorectical analysis and by using experimental data. There was a difference between the natural frequency calculated theorectically and experimentally. I was asked to discuss the...
  22. C

    The 'natural frequency' of an object. What does this mean?

    What does it mean to say that something, for example a bridge, has a natural frequency? Does this have anything to do with how long it is?
  23. F

    Natural frequency of tuning fork

    Homework Statement Using a highly sensitive parabolic sound collector, Sara records the frequency of a tuning fork as it drops into the Grand Canyon. She drops the vibrating tuning fork form rest at t=0. She records a frequency of 1783.0Hz at t=8.590s. What is the natural frequency of the...
  24. J

    Find the natural frequency of a system of two pendulums

    Homework Statement OK I haven't been given a definite question with values, but how would you find the natural frequency of a system of two pendulums coupled by a spring? Homework Equations a= -gx/l T=2pi sqrt(l/g) The Attempt at a Solution Well the thing is, I know I need to...
  25. P

    How do you determine the natural frequency of a solid?

    All solids have a natural frequency but how do you determine its value? How would you determine it for a large building? I'll guess that for each different material they apply a constant external force with a specific angular frequency. The force with an angular frequency that breaks the...
  26. J

    Measuring the Natural Frequency of Concrete: Techniques and Considerations

    Does anyone know of any way to measure the natural frequency of concrete? Any input would be extremely helpful, even if the method does require sophisticated technology or machinery :smile:
  27. C

    Natural Frequency Explained in Layman Terms

    can anybody tell what is a natural frequency in lay man terms. any website?
  28. S

    Natural frequency of a wine glass

    Does anybody know the typical natural frequency of an empty wine glass? I want to conduct a demo experiment of breaking a wine glass with a sound wave from a distance. Has anyone here done it before? I need a signal generator (sine wave) and an amplifier. What kind of loudspeaker do I have...
  29. K

    Find Natural Frequency of Structure: Cube (Box) of Honeycomb Sandwich Panels

    What is exact procedure to find the Natural Frequency of a structure...i.e a cube (box) of Honeycomb Sandwich Panels...i have simulated the Modal Analysis in Ansys...there i got the natural frequency of very low amount ...almost 0.3Hz for First Mode,0.5 Hz for Second Mode and so on...i think it...
  30. C

    Solving for Natural Frequency in a Si-Based NEMS Resonator

    NEMS Resonator I need a hint to help with my homework. The question: "A Si-Based NEMS resonator has dimensions length=150nm, width=5nm and thickness=5nm and an effective spring constant of 100Nm^-1 and natural frequency of vibration of 250MHz" I am looking for an equation linking the...
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