Longitudinal waves: wave movement is parallel to particle movement.
Acoustic Velocity (v): n = ¦ ´ l where ¦ = frequency and l = wavelength in material. Focal length of the transducer is dependent on acoustic velocity of the particular material.
Frequency (f): ¦ = n ¸ l . Lower frequency provides deeper penetration, but higher frequency provides better resolution. Transducer frequency ranges from » 5 MHz to 150 MHz.
The minimum detectable defect: this should be greater than or equal to _ l .
Sound reflectance (Pr ): Pr = , where Z1 is the acoustic impedance of the first material, and Z2 is the acoustic impedance of the second material. |