Investigation of initiation and evolution of delamination in glass/epoxy laminated composites using acoustic emission method

In order to access the reliable structures, detection of the damages initiation and evolution in materials is necessary. Delamination is the most common failure mode in laminated composites. The present study is concerned with an investigation of initiation and propagation behavior of delamination using Acoustic Emission (AE) method. In this work, various lay-ups of glass/epoxy composite laminates have been fabricated and subjected to mode I quasi-static loading condition. The behavior of delamination is investigated in two sections. In the first section, the main focus is on the initiation of damage. In this section, initiation of various damage mechanisms are determined using AE method. In the second section, evolution of delamination is investigated using AE. In order to determine the instantaneous crack tip position during the propagation of delamination, at first, AE wave velocity in the specimens is specified. Then, using the proposed method, unwanted signals are eliminated. The obtained results indicate that AE method has a good performance to detect initiation stage of interlaminar damage and also to determine the delamination propagation in the laminated composite structures.