From: [email-masked] (Philip.M. Sargent)

Subject: Re: Speed of sound in Plexiglas?
Message-ID: <[email-masked]>
Date: 1 Apr 92 13:02:47 GMT
References: <[email-masked]>
Sender: [email-masked] (Philip.M. Sargent)
Organization: cam.eng
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Nntp-Posting-Host: club.eng.cam.ac.uk

[email-masked] (Dean Pentcheff) writes:
>Can anyone give me some pointers on where to look to find out what
>the speed of sound is in various plastics (Plexiglas for starters)?

Just look up the density and tensile (Youngs) modulus, the speed of sound
is the square root of (modulus/density). That gives the longitudinal
wave speed, shear wave speed: just replace Youngs modulus with the shear
modulus.  Of course you have to be careful that you use a value for the modulus
derived at a frequency similar to the sound you are intrested in - polymers
have very strong dependence of modulus on frequency so a Youngs modulus
measured from a 'static' test will give you too low a value.
--Philip 
CUED, Cambridge UK
End of article 214 (of 214)--what next? [npq] Article 217 in sci.materials:
From: [email-masked] (John Prentice)

Subject: Re: Speed of sound in Plexiglas?
Message-ID: <8=[email-masked]>
Date: 1 Apr 92 19:33:31 GMT
References: <[email-masked]>
Organization: Dept. of Physics & Astro, University of New Mexico, Albuquerque
Lines: 21

In article <[email-masked]> [email-masked] (Dean Pent cheff) writes:
>Can anyone give me some pointers on where to look to find out what
>the speed of sound is in various plastics (Plexiglas for starters)?

Well, here is one number.  For PMMA, the bulk (longitudinal) sound speed
is 2.60 mm/microsecond.  That is courtesy of a little party favor handed
out at the 1989 APS Topical Conference on Shock Waves in Condensed Matter.
As a general rule, that community has an abundance of data on the constitutive
properties of plastics, particular sound speeds.  You migt contact the
shock physics people at Los Alamos or Sandia.  The proceedings of those
shock physics conferences are published by North Holland and have alot of
info like this too.

--MORE--(79%)

Good luck!

John
-- 
John K. Prentice                      | "We must make good the demands of
Department of Physics And Astronomy   | reason and create a life worthy of
University of New Mexico              | ourselves and of the goals we only
[email-masked]                 | dimly perceive."  - Andrei Sakharov
End of article 217 (of 217)--what next? [npq]