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Re: Acoustic Attenuation

Posted by: W. Grandia , E-mail: WGRANDIA@aol.com, on October 01, 1996 at 10:41:46:

In Reply to: Acoustic Attenuation posted by : Derek Stewart on September 27, 1996 at 19:50:15:

I looked up the information for the acoustic parameters in Tungsten and found something in the book from Prof Gordon Kino: Acoustic Waves with subtitle: Devices, Imaging & Analog Processing; Prentice Hall ISBN 0-13-003047-3. Page 551.
This is a table generated by Dr. Allen Selfridge.
It states:
V_l = 5.2 (km/s)
V_s = 2.9 (km/s)
Density_mo = 19.4 (kg/m³ x 10 ⁶)
Z_l = 101.0 (density x long. velocity)
Z_s = 56.3 (density x shear velocity)
s = 0.27 (dB/cm)
The attenuation A = a/f² dB. s ²/m x 10 ^-15)
(No value of A at any frequency was given)

Further more there are some Tungsten parameters given in "Ultrasonics, fundamentals , applications by Dale Ensminger., page 210, book ISBN: 0-8247-7659-3
No attenuation information is given, however it states the following useful information:
1) Tungsten: Bar (c₀) = 4.60, Bulk (c_B) =5.18, Shear (c_s ) = 2.87, Dens=19.25,
Characteristic impedance (rc_B) = 9.98, Poisson's ratio 0.28,
2) Tungsten annealed: Bar (c₀) = 4.62, Bulk (c_B) =5.22, c_s=2.89, Dens=19.30,
Characteristic impedance (rc_B) = 10.07
3) Tungsten: Bar (c₀) = 4.31, Bulk (c_B) =5.46, c_s=2.62, Dens=19.10, Characteristic
impedance =10.42
4) Tungsten, drawn: Bulk (c_B) =5.41, c_s=2.62, Dens =19.30, Characteristic
impedance =10.44
5) Tungsten: (c_B) =5.17, c_s=2.62, Dens =19.30, Characteristic
impedance =10.00, reference 24
The above information is probably not sufficient. Attenuation is influenced by absorption, grain structure, beam spreading, hysteresis and temperature. It is probably the best to make some simple measurements to derive the numbers for the specific application.
In regards to attenuation of guided plate wave modes in Tungsten, the problem becomes very complex to calculate and again, it is probably best to measure it.

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Comments:
: I looked up the information for the acoustic parameters in Tungsten and found something in the book from Prof Gordon Kino: Acoustic Waves with subtitle: Devices, Imaging & Analog Processing; Prentice Hall ISBN 0-13-003047-3. Page 551. : This is a table generated by Dr. Allen Selfridge. : It states: : V_l = 5.2 (km/s) : V_s = 2.9 (km/s) : Density_mo = 19.4 (kg/m³ x 10⁶) : Z_l = 101.0 (density x long. velocity) : Z_s = 56.3 (density x shear velocity) : s = 0.27 (dB/cm) : The attenuation A = a/f² dB. s ²/m x 10^-15) : (No value of A at any frequency was given) : Further more there are some Tungsten parameters given in "Ultrasonics, fundamentals , applications by Dale Ensminger., page 210, book ISBN: 0-8247-7659-3 : No attenuation information is given, however it states the following useful information: : 1) Tungsten: Bar (c₀) = 4.60, Bulk (c_B) =5.18, Shear (c_s ) = 2.87, Dens=19.25, : Characteristic impedance (rc_B) = 9.98, Poisson's ratio 0.28, : 2) Tungsten annealed: Bar (c₀) = 4.62, Bulk (c_B) =5.22, c_s=2.89, Dens=19.30, : Characteristic impedance (rc_B) = 10.07 : 3) Tungsten: Bar (c₀) = 4.31, Bulk (c_B) =5.46, c_s=2.62, Dens=19.10, Characteristic : impedance =10.42 : 4) Tungsten, drawn: Bulk (c_B) =5.41, c_s=2.62, Dens =19.30, Characteristic : impedance =10.44 : 5) Tungsten: (c_B) =5.17, c_s=2.62, Dens =19.30, Characteristic : impedance =10.00, reference 24 : The above information is probably not sufficient. Attenuation is influenced by absorption, grain structure, beam spreading, hysteresis and temperature. It is probably the best to make some simple measurements to derive the numbers for the specific application. : In regards to attenuation of guided plate wave modes in Tungsten, the problem becomes very complex to calculate and again, it is probably best to measure it.

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