An inspection system for non-destructively detecting physical defects in solid shafts by launching and receiving longitudinal acoustic waves has been described incorporating a transducer head containing a transducer head containing a matrix of transducers, pulsers, pulse width modulators, preamplifiers and a summing amplifier. A fiber optic cable may couple the transducer head to a remote location containing a receiver and a oscilloscope. The invention overcomes the problem of launching longitudinal acoustic waves with insufficent energy. Further, the invention overcomes the problem of asymmetric load conversions affecting the output signal arising at times when only one transducer is used and is positioned off center with respect to the solid shaft.
Glenn M. Light; Edward A. Bloom; Soung-Nan Liu