Study On Drilling Technology Of Fiber Metal Laminates

The composite material is used more and more widely in the manufacture ofaircraft currently, however, problems associated with the processing of newcomposite material are increasing. Fiber metal laminates (FMLs) are a hybridcomposite sandwich structure comprising of multiple layers of a thin aluminumalloy and alternating layers of glass fiber reinforced resin matrix composite material.Since the material shows great performances in anti-fatigue property and specificstrength, FMLs satisfy the requirements of the aircraft structure and have broadprospects in the aviation sector. FMLs have been used in, for example, C919, B787,A380and some others.The material of the tools, the geometrical shape of the drill, axial force andtorque of the drill are among the causes which impact on the quality of drillingprocess. It could improve the quality of holes to use carbide drills, and throughcontrolling the rotating speed and rotating speed of the drill and decreasing axialforce and torque of the drill, the probability of delamination of the FMLs would belower.This paper is based on the drilling process of FMLs, in which has had sometheoretical analysis and experiments done on the processing. Theory models werebuilt to have analytical solution on the drilling process. Experiments wereimplemented in order to verify the theory models. The selecting method of toolswas also created and some examples were given.Based on the structure of FMLs, the current paper introduced a mechanisticmodel of FMLs, using linear elastic theory, principle of virtual displacement,classical plate theory and composite laminate theory.Some parameters of the drill, that is, the material, the geometrical shape, werestudied through experiments to evaluate their impact on the processing. As well, therotating speed and rotating speed of the drill and tool-abrasion were considered inthe experiments to study their effect on the hole-quality.Single factor analysis method was adopted to assess how various drills,different rotating speed and rotating speed would affect the axial force, torque andthe hole-quality. Evaluating parameters were introduced as standard parameters tochoose some tool，machining parameters were determined.Drilling mechanism of FMLs was analyzed through the numeric analysis studyand the experiments, which brings an analysis method on the drilling process.