Characterisation of drilling-induced damage in GFRP Honeycomb Sandwich Composites using Acoustic Emission

Glass Fiber-reinforced plastic (GFRP) sandwich composites are extensively used in various engineering applications owing to their advantageous structural properties such as high specific strength to weight ratio, resistance to shear and compressive forces as well as their cost-effectiveness and manufacturing ease. Machining these composites however is a difficult task. The durability of the material deteriorates due to machining induced meso-damage that accumulate over time, creating the motivation to study what the damage mechanisms depend on. Many NonDestructive Testing (NDT) techniques are often used to characterize such damages. Acoustic Emissions (AE) has emerged as an important nondestructive method for real-time examination of damage evolution. This study aims to investigate the effects of various acoustic emission features along with force, torque and tool wear on the delamination caused on the GFRP sandwich honeycomb composite during the drilling process. Experiments were conducted and delamination for each hole was measured. Consequently, data-driven models were used to characterize damage in the material.