SEDL / STP / STP972-EB / STP26146S

The Use of Acoustic Emission to Detect the Onset of Interlaminar Shear Failure in Short Beam Fatigue Specimens

Edwards, JH
Managing director, Testwell, Ltd., Daventry,

Pages: 11    Published: Jan 1988

Download this paper for $25 PDF (456K)          View License Agreement
Abstract

Interlaminar shear failure caused by fatigue loading has been studied in carbonepoxy and glass-epoxy unidirectional composites. Short beam specimens were subjected to three-point bending loading with low mean stress, high mean stress, and zero mean stress at a range of alternating stresses to give lives in the range 10⁴ to 10⁷ cycles.

The indications of incipient failure given by acoustic emission were confirmed by ultrasonic Cscan and cutup. Of 150 specimens, only five failed to be confirmed by all three techniques.

After some initial trials to determine optimum gain levels and the addition of a voltage-controlled gate, acoustic emission proved simple to use, reliable, and accurate.