Acoustomagnetic TPU / SEG calculation model

[TechStuf]

The acoustic wave is a travelling type standing wave

Better than I got. 


All I've been able to achieve thus far, are the stationary type sitting waves.





TS

[BEP]

Ok. We all know a not-standing-standing wave is a misnomer. The same for just 'standing wave'. If it is standing then it isn't a wave. Most use the term to describe the crossing of a source wave and its reflection.
Sorry, what is being discussed are compression waves.

I won't partake in a futher discussion of such magnetic waves not existing. You can take that up with builders of cyclotrons, fluorescent lights, and waveguides. No, plasma is not required. All the wave needs is a contained path.

BEP

[EMdevices]

I like those Q values  Mark ,  magnetostriction effects (or magnetoacoustic)  are wonderful !

As we know,  bandwidth  is  equal to  F/Q,  where F is the center frequency,  so if you have a high Q value, then your bandwidth will be very very small, which means,  TUNE VERY SLOWLY AND FINE INCREMENTS or you'll miss the effect.   Also we note as F goes down the bandwidth decreases for a given Q value,   so when we start talking about   high Q and low frequencies like SM mentions,  we're talking about phenomena that can be easily missed in a lab setting.

EM

[MarkSnoswell]

LOL -- yea -- in my iron rods the Qs are 7,000 - 13,000 ... let me explain further:

you are looking for a resonant peak at 87,000 Hz -- it's only got a 6.5 HZ 1/2 height bandwidth... you have to have the magnetic bias just right .. your magnetic bias must not restrict the motion of the ends of the rod so you cant just stick magnets on...

That paints a picture of how incredibly hard it is to find the effect -- but once you do its very easy to reproduce.

I have no doubt that the TPU style of devices are also very difficult to tune in their own way -- and then with experience it becomes easy to reproduce.

[braden]

This may be of interest
http://www.wipo.int/pctdb/en/wo.jsp?KEY=04%2F64223.041028&IA=US2004000013&DISPLAY=STATUS