Monitoring Damage Progression in Center-Notched Boron/Aluminum Laminates Through Acoustic Emission

This study concentrated on monitoring damage initiation and progression through acoustic emission in center-notched boron/aluminum laminates subjected to quasi-static tensile loading. Laminates studied include [0]₈, [90]₈, [±45]_2s, [0/90]_2s, [0/±45/0]_s, and [0/±45/90]_s 5.6-mil boron/aluminum 6061-F. The objective of this study was to investigate the potential of the acoustic emission technique for locating existing damage, detecting and tracking damage initiation and progression, identifying potential fracture sites, and distinguishing among the major failure mechanisms of the different laminates. Emphasis was placed on developing the proper test methodology for characterizing a new composite material system through acoustic emission. For base-line data, mechanical properties, fracture behavior, and deformation characteristics were studied and acoustic emission was recorded for the composite constituents (namely, fiber and matrix) as well. A good degree of reproducibility has been established. Acoustic emission results could be correlated with the deformation characteristics of the subject material, and failure modes and processes for the various laminates could be identified.