Vibration characteristics of rotating aerofoil cross section bladed disc assembly

摘要: The purpose of this thesis is to analyse the vibration characteristics aerofoil cross-section straight and pretwisted blades blade packets on infinitely rigid discs shrouded flexible under rotating conditions using finite element method. In first part analysis a carried out by assuming that fixed at periphery an disc constant angular velocity. effect pretwist, stagger angle, rotational speed distance shear centre from centroid investigated. A model developed asymmetric tapered beam. assumption made variation cross-sectional properties along which given Chebyshev polynomial approximated quadratic polynomial. This applicable for variable beam whose are defined some discrete points length. To investigate behaviour packet shroud assumed have curvature analysed curved elements. Two in-plane one out-of-plane elements with internal node mid-point each developed. It shown converges faster than without node. effects thickness, width, speed, radius, case it introduction overall matrix size consequently computing time problem reduced markedly. Various tests also out. Finally flexibility or non-rotating considered. reduce method used in conjunction wave propagation technique cyclic symmetry. For phase difference between bendings torsional modes length bladed-disc illustrated. angles, bladed shrouded-bladed-discs series disc, staggered, pretwisted-bladed-disc Experimentally observed mode shapes compared theoretical shapes. Furthermore dynamic assembly twenty, two-bladed elastic investigated can be estimated independent disc.