Active stabilisation of a piezoelectric fiber composite shaft subject to follower load

Abstract

The paper is concerned with active stabilisation of self-excited vibration of slender rotating columns subject to tangential follower forces. Such systems exhibit flutter-type instability as a result of energy transfer from rotation and to transverse motion of the shaft. There are two reasons for the instability to occur in rotating slender shafts––rotation in the presence of internal friction in the shaft material, and the follower load. The study reveals an interesting coupled effect of these parameters on the system stability as they create a concave set in which the system remains stable, and this means that one parameter neutralises influence of the other. The paper also takes up the problem of near-critical behaviour of the system. Non-linear bifurcation analysis is carried out to predict type of the self-excitation (either soft or hard), near-critical vibration amplitude and jump phenomena. In the second part of the paper a method of active stabilisation based on making use of piezoelectric fibre composites (PFC) is presented. The composites containing active fibres made of piezoceramics constitute the state-of-the-art structural materials capable of adjusting their mechanical state according to dynamic loading conditions. Some fundamentals concerning the operation of PFCs as rotating columns are given in the paper.