Acoustic Emission of Failure in Fiber-Metal Laminates

Abstract

This paper studies the failure modes of Glare grades under tensile loading by means of Acoustic Emission (AE). AE transients produced by various types of microdamage, such as yielding, matrix crack initiation, matrix-fiber debonding, matrix cracking and fiber fracture, were recorded as functions of strain for various Glares and fiber orientations. Experiments showed that different microdamage mechanisms produced characteristically different AE signals which can be classified into categories based on peak amplitude and total counts parameter ranges. Moreover, it was observed that AE percent count rate is a function of the normalized strain and metal volume fraction (MVF) in similar Glare lay-ups. In addition, AE profiles were found to exhibit exponential growth behavior in the initial region of the profile and a power growth behavior after the knee point.