CRITICAL ISSUES IN STRENGTH EVALUATION OF TURBO MACHINERY BLADE DISK ASSEMBLY AT CONSTANT RPM

In this present work, 3D Finite Element Analyses (FEA) of Low Pressure (LP) steam turbine bladed disk assembly are carried out at a constant speed loading condition. The prime objective of this work was to optimize the geometry of bladed disk root with the aid of Peterson’s Stress Concentration Factor (SCF) charts available in literature. Secondly design rules are developed for structural integrity of blades and disc considering a common factor for material, manufacturing and temperature uncertainties.These design rules are in turn used as design checks with aid of finite element analysis results. Special investigations were been performed based on Neuber formulae for reducing the local peak stresses at blade and disc root fillet using linear Analysis to identify the equivalent non linear stress value by strain energy distribution method for estimating the minimum no of cycles required for crack initiation by Low Cycle Fatigue (LCF) calculations