Online monitoring of drilling carbon fiber reinforced polymeric nanocomposite laminates using acoustic emission technique

Abstract

The broad area of this research is machining of Polymer Matrix newlineComposite (PMC). Composite materials can be defined as materials newlineconsisting of two or more constituents that are combined at the macroscopic newlinelevel and are not soluble in each other. Composites are composed of two newlinephases, namely matrix and reinforcement. PMCs have a matrix which is made newlineof a thermoset or a thermoplastic polymeric resin. The most common types of newlinereinforcement used for PMC are strong and brittle fibers incorporated into a newlinesoft and ductile polymeric matrix. Hence PMCs are generally referred to as newlineFiber Reinforced Plastics (FRP). FRP composites have been steadily replacing metals as choice newlineengineering materials for various applications because of their very high newlinespecific strength and stiffness. Among all the FRPs, Carbon Fiber Reinforced newlinePlastic (CFRP) is much sought after material because of its light weight, very newlinehigh strength and high stiffness. Recently, polymeric nanocomposites have newlinefound greater application in the area of aerospace and defence sectors. In FRP composite laminates, when nano particles are dispersed in newlinethe polymer matrix, the composite may be referred to as nanocomposite or newlinehybrid composite. CFRP nanocomposites are the hybrid of CFRP composites newlinein which the reinforcement has at least one of its dimensions in the nanometer newlinerange. These nanocomposites show great promise not only in terms of superior mechanical properties, but also in terms of superior thermal, newlineelectrical, optical, and other properties. In general, there are two types of nano newlinereinforcements, namely Carbon Nano Fibers (CNF) and Carbon Nano Tubes newline(CNT) which are used in the matrix of the CFRP nanocomposites. Even newlinethough the FRP components are mostly produced near net shape, machining is newlinefrequently required in order to bring the component into dimensional newlinerequirements and prepare it for assembly. Out of all the machining operations, drilling is the most frequently newlineemployed operation for FRP composite laminates owing to the need for newlinejoining structures.