Calculating the fundamental resonance of an object (not string)

[alexr963]

Hello everyone, im new here seeking an answer and hopefully more in the future.

I'm in a dilemma, there is a way of calculating the fundamental frequencies, i.e the resonance of a string, however i need o work out the resonance of an object.

for example, if you ping a wine glass, itl give you a frequency (usually about 500hz) and if you play that frequency to the glass, it'l begin to move and eventually shatter because of the wave pressure "match" the frequency of the glass thus resonating with it.

ive included the formula for the resonance frequency, however i have no idea how to apply this to mass and density of object, as apposed to the tension and length and mass of a string.

i perhaps think that tension could be replaced with the density, then the length as diameter and mass as mass, or volume?

the objects i want to find out the resonance frequencies of, is highly inaccessible and is more complicated than tapping it, and then working out the pitch by ear.

ive looked around and i cant find anything, if anyone has any ideas, i would be very grateful, thank you.

Edited July 19, 2017 by alexr963

[Strange]

Most objects don't have a resonance frequency. They might have several frequencies that they will absorb, or vibrate at. Or none.

[studiot]

Yes it kinda depends upon the shape object, and, as Strange says, the material of the object may cause excessive damping.

So a plasticine wine glass will not ring but a glass one can.

You are not clear as to the shape, but taking your wine glass example here is an extract from a table of natural frequencies.

 

 

[alexr963]

Im trying to work what would be the relative frequency of planets, since frequency can be doubled or halved to find the relative octaves, in case its a frequency beyond our hearing

[Country Boy]

 As strange said "Most objects don't have a resonance frequency."  A resonance frequency is typically connected to a crystalline structure so that every part has the same frequency.  What makes you think that a planet, made of many different substances, has a single resonance frequency.