Sign up Calendar Latest Topics Donate
 
 
 


Reply
  Author   Comment   Page 2 of 2      Prev   1   2
Curran919

Avatar / Picture

Sr. Member / Supporter
Registered:
Posts: 599
Reply with quote  #16 
Quote:
Originally Posted by John from PA
http://www.differencebetween.com/difference-between-fundamental-frequency-and-vs-natural-frequency/ Interesting, but more toward physics, signal theory, etc.


That article was very inaccurate. Much of what he said was just wrong. The rest was poorly written.

Every system has a property called the natural frequency. It normally has many, depending on the number of degrees of freedom.

The system will follow this frequency, if the system is to be provided with a small oscillation. An oscillation is periodic. The system will vibrate at the same frequency as the oscillation. This is absolute bullshit.

Events such as earthquakes and winds can do destruction on objects with the same natural frequency as the event itself. Earthquakes and wind are excitations and don't technically have a natural frequency. Its an excitation frequency.

Now imagine a periodical external force applied to the system. The frequency of this external force does not necessarily be similar to the natural frequency of the system. This force will try to oscillate the system to the frequency of the force. This creates an uneven pattern. Some energy from the external force is absorbed by the system. Just... what?

Another important bit to note. Referring to the lowest natural frequency as a fundamental frequency, assumes a system where the subsequent natural frequencies will be odd integer multiples of the fundamental frequency, such as a guitar string. This actually corresponds to only one-dimensional systems, like a string or axial waves in a bar, etc. A complex 3D system will not have the same integer relationship between its eigenfrequencies, and is therefore the lowest eigenfrequency is not fundamental of anything.
JULIO BALLON

Member
Registered:
Posts: 3
Reply with quote  #17 
I think the same as Rusty, and is the clearest way to locate the fundamental frequency and relate our diagnosis in function to it, or to the frequency that are born from the fundamental ....
JULIO BALLON

Member
Registered:
Posts: 3
Reply with quote  #18 
The speed of rotation, FPA, the frequency of slots, gearmesh frequency, LF, are the product of the fundamental frequency, all depend on the fundamental frequency, whether multiples, harmonics or sub multiple, all are a result of the frequency that generates the movement of the Axis we are observing
Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.