J0420303 Higher Harmonic Imaging of Anomalies in Metal by a 100MHz Burst Sine Wave Pulser

Abstract

By using a burst sine wave pulser of 100MHz range, high-pass filters, an amplifier and imaging software, we imaged non-metallic inclusions in a SUS 304 steel plate, interface disbond of a SiC/Ti composite by tensile loading and local plastic deformation in SUS 304 plate. The images of anormalies obtained by 35MHz sine wave of 2 cycles and 80 MHz high-pass filter have much higher resolution than those obtained by 20MHz sine wave of 2 cycles and 40 MHz high-pass filter. By a local resonance technique, image resolution of local plastic deformation in a SUS 304 perforated plate subjected to 30% plastic strain at maximum is also improved markedly.