Epoxy cure monitoring using ultrasonic spread spectrum binary signals

Abstract

Procedure for dual component epoxy cure monitoring is presented. Accurate time of flight estimation was used employing the correlation processing. Several spread spectrum signals have been put in comparison with conventional pulse and toneburst signals. Experimental results presented indicate that reliable separation of curing phases can be established using both ultrasound velocity and attenuation measurements. Lowest velocity variation was produced by 4 MHz toneburst signal.