Natural frequency Definition and 129 Threads

Homework Statement Hi. I'm trying to work out the undamped natural frequency of a cantilever beam. The setup of the system is shown in the image below. http://www.flickr.com/photos/56901717@N03/5249378659/ Data:(all lengths measured from the hinge on the left of the beam) Beam...

Hello, I am taking a vibrations course and we are currently talking about using PDEs to find responses of beams. In the book, there is an equation to find the natural frequencies of a simply supported beam under an axial load: omega = (pi^2/l^2)*sqrt(EI/roA)*sqrt(n^4 + (n^2*P*l^2)/(pi^2*EI))...

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...

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..

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...

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?

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...

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...)?

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...

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?

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

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...

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...

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...

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...

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?

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)...

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...

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...

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...

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?

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...

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...

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...

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:

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

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...

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...

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...