Characterisation of Nonlinear Aeroservoelastic Behaviour
Abstract
The characterisation of the behaviour of nonlinear aeroelastic systems has become a very important research topic. Nevertheless, most of the work carried out to date concerns the development of unsteady CFD solutions in the transonic region. Important though this work is, there is also a need for research which aims at understanding the behaviour of nonlinear systems, particularly the occurance of Limit Cycle Oscillations (LCOs). The purpose of this paper is to study the stability of a simple aeroservoelastic system with nonlinearities in the control system. The work considers both structural and control law nonlinearities and assesses the stability of the system response by use of bifurcation diagrams. It is shown that simple feedback systems designed to increase the stability of the linearised system also stabilise the nonlinear system, although their effects can be less pronounced. Additionally, a nonlinear control law designed to limit the control surfaces pitch response was found to increase the flutter speed considerably by forcing the system to undergo limit cycle oscillations instead of fluttering. Finally, friction was found to affect the damping of the system but not its stability, as long as the amplitude of the frictional force is low enough not to cause stoppages in the motion.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2000
- Accession Number
- ADP010481
Entities
People
- G. Dimitriadis
- J. E. Cooper
Organizations
- University of Manchester