A Study on Low Velocity Impact Behaviour of Functionally Graded Sandwich Conical Shell Under Thermal Environment

Abstract

Abstract Turbo machinery rotating blades are a vital component of aero-engines for transferring the energy of gas flow to kinetic energy. Rotating turbo-machinery blades are prone to fail under working field with high temperature, high speed, high pressure and impact of blades. Recently Functionally graded materials (FGMs) are used in turbo-machinery blades due to its advantage of delamination and debonding free structure and ability to withstand high temperature during operation. As these aero-engine blade works in high temperature condition therefore use of ceramic FGM in the outer surface of the blades gives potential advantage. However, low velocity impact is a potential hazard of the blade due to rigid structure of the blade while considerable thickness of ceramic present in the outer surface of the blade. The chances of impact failure of the blade also increase in that case. Hence, low velocity impact of the turbo-machinery blades need to study carefully for safe and reliable operation of the engine. In this present work the low velocity impact characteristics of the FGM sandwich turbine blade under various operating temperature are determined using finite element technique. The low velocity impact performances are evaluated in terms of time histories of the contact force, velocity of the projectile, shell deflection and indentation considering various impactor initial velocities, core to FGM thickness ratio (hcore/hfgm) and blade operating temperature. The upper and lower surfaces of the functionally graded structure reinforced by ductile pure metal layers appear to play a significant role in protecting the structure’s functional integrity from damage.