Toward automated identification and quantification of meso-scale damage modes in plain weave glass/epoxy composite laminates

Abstract

We investigated three different automated methods for identification and quantification of meso-scale damage on single-layer composite laminates subjected to ballistic impact by a 5.5 mm (0.22 caliber) right circular cylindrical steel projectile. These methods were based on the combined use of high-resolution optical imaging, fluorescence microscopy, and image detection software. High-resolution images of impacted composite samples were processed using either ImageJ alone (method 1, for sample size of 20 × 20 cm²) or ImageJ plus MATLAB (method 2, for sample size of 20 × 20 cm²), or fluorescence images were processed using ImageJ plus MATLAB (method 3, for sample size of 6 × 5 cm²). These methods were used for identification and grouping of horizontal and vertical transverse tow cracks, and 45° matrix cracks. The identified and grouped damage modes were quantified based on spatial pixel count related to damage modes, and quantified damage modes were used to generate a digital damage map using a separate MATLAB code for all three methods. Finally, the advantages and shortcomings of each of these three automated methods for identification and quantification of meso-scale damage modes were evaluated via comparison to a baseline manual method for identifying and quantifying the damage modes on the same samples.