Detection of Damage in Composite Materials by Thermo-Acoustic Emission Measurement

Abstract

Characteristic acoustic emission behavior was observed when a composite was subject to a thermal cycle (thermo-acoustic emission). A lot of emission was observed in the ther mal cycle for a composite which had damage induced by mechanical loading. On the other hand, the emission was hardly observed for a sound composite in the thermal cycle. The occurrence of the emission was restricted only to the composite with damage. Further more, the emission activity depended on the degree of the damage. The emission is con sidered to be generated due to the friction of the crack faces by the thermal loading. The thermo-acoustic emission measurement is considered to be anticipated as nondestructive evaluation for composite materials.