An experimental and empirical assessment of machining damage of hybrid glass-carbon FRP composite during abrasive water jet machining

Fiber reinforced polymer (FRP) composite materials have huge demand in various fields due to their low weight and better mechanical qualities. Machining of FRP composite materials without damage is quite difficult using traditional machining systems owing to their intrinsic anisotropy, heterogeneity, and temperature sensitivity. Abrasive water jet machining (AWJM) is a known versatile technique to address the machining of FRP composite with minimal damage. However, kerf taper and delamination are the significant damages usually recorded in AWJM. The present work aims to minimize the above-said damages by applying a hybrid grey relational analysis (GRA)-principal component analysis (PCA) mathematical model. The glass and carbon fibers are used as reinforcements in the epoxy matrix. Nine experiments are conducted by considering hydraulic pressure, the mass flow of abrasive, standoff distance and transverse speed as machining parameters at three different levels each. The experimental and empirical results reveal that the mass flow of abrasive and hydraulic pressure are significant parameters to minimize the kerf damage, whereas the mass flow of abrasive and standoff distance are the parameters to reduce the delamination damage. The confirmation experiment based on the recommended optimized parameter records the reduction in delamination damage and kerf width damage to 33.9% and 11.72%, respectively. The adequacy and accuracy of the proposed mathematical model is being performed with the value of indicators R2 and adjR2, which are all closer to one.