Analysis of Fir Tree Root of Aero-engine Disc Assembly for Simultaneous Optimization of Fretting Characteristics

Abstract

An aero-engine fir tree blade disc assembly is much proven to fretting fatigue damages due to centrifugal and vibrating conditions. This paper examines the effect of disc speed, contact angle and co-efficient of friction on fretting responses such as equivalent von-Mises stress, maximum shear stress and contact pressure by adopting Taguchi based grey relational analysis and RSM. All of the fretting responses were influenced by disc speed and contact angle. Multi response optimization achieved using grey relational analysis indicated that minimum equivalent von-Mises stress (0.63 MPa), shear stress (0.36 MPa) and contact pressure (0.681 MPa) are achieved at 260 rpm of disc speed, 17.5° of contact angle and 0.3 co-efficient of friction. Significant improvement was noticed in terms of stress concentration reduction at optimal conditions. Confirmatory simulation runs were performed to ensure the grey relational analysis results.