SNAP
FOR THE STUDY OF NONLINEAR ACOUSTIC PHENOMENA
In the last few years, considerable attention has been focused on using nonlinear ultrasonic properties for the nondestructive evaluation of materials. Some examples of important applications include: metal fatigue, micro cracking, bond strength of adhesives, metal embrittlement, and properties of coatings. The RITEC SNAP incorporates a number of unique circuits designed to facilitate the determination of these properties using a variety of techniques :
- Harmonic generation in the sample can be monitored as a function of the driving sound amplitude.
- Acoustic resonances may be examined at high and low amplitudes.
- Beam mixing at two driving frequencies can be studied using two high-power, gated amplifiers.
- In some cases simple amplitude dependence may used to obtain valuable results.
Gated-amplifier, high-power outputs are obtainable over a frequency range far in excess of one decade. Typical high-power (5KW) frequency ranges are 0.05 to 5 MHz and 0.5 to 7 MHz. At 1KW these ranges are extended to ~5 and just under 20 MHz respectively. In the SNAP system, however, the superheterodyne receiver may be independently tuned up to 80 MHz without loss of phase coherency.
