This chapter introduces the Rayleigh‐Ritz approach for modelling a system using a series of assumed shapes, as a way of representing continuous systems with relatively simple geometries (e.g. uniform cantilever wings). It considers special cases where the assumed shapes are in fact normal modes of the whole aircraft, or ‘branch modes’ of parts of the aircraft. The wing, tailplane and fuselage are mainly treated as uniform, straight and thin‐walled slender members. In order to carry out a dynamic analysis involving such members, it is helpful to understand the so‐called shear and flexural centres and the corresponding axes. The chapter performs an analysis for a uniform built‐in member (or ‘wing’) under bending or torsional vibration, with one or two simple polynomial terms used in the series. It explains first approach to determine whole aircraft free–free modes.
Vibration of Continuous Systems – Assumed Shapes Approach
2014-12-02
20 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
Effect of normal mode contents in assumed deflection shapes in Rayleigh-Ritz method
Online Contents | 1996
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