Advanced aeroelastic robust stability analysis with structural uncertainties
- PDF / 2,108,468 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 20 Downloads / 170 Views
ORIGINAL PAPER
Advanced aeroelastic robust stability analysis with structural uncertainties Özge Süelözgen1 Received: 29 February 2020 / Revised: 19 June 2020 / Accepted: 21 September 2020 © The Author(s) 2020
Abstract Robust flutter analysis described in this paper is based on the robust control theory framework. Therefore, a time-domain linear fractional transformation representation of the perturbed aeroelastic system is modeled. Then, the robust stability is analyzed by means of the structured singular value 𝜇 , which is defined as an alternative measure of robustness. Robust flutter analysis deals with aeroelastic (or aeroservoelastic) stability analysis taking structural dynamics, aerodynamics and/or unmodeled system dynamics uncertainties into account. Flutter is a well-known dynamic aeroelastic instability phenomenon caused by an interaction between structural vibrations and unsteady aerodynamic forces, whereby the level of vibration may trigger large amplitudes, eventually leading to catastrophic failure of the structure. The primary motivation of the robust flutter analysis is that this method allows the computation of the worst-case flutter velocity which can support, for example, the flight test program by a valuable robust flutter boundary. This paper addresses the issue of an approach for aeroelastic robust stability analysis with structural uncertainties with respect to physical symmetric and asymmetric stiffness perturbations on the wing structure by means of tuning beams. Keywords Robust flutter analysis · 𝜇-Analysis method · LFT modeling · Aeroelasticity · Robust stability analysis · Uncertain systems
1 Introduction The primary aim of this paper is to investigate the impact of the stiffness uncertainties of the wings in spanwise direction and handle each wing separately in case of symmetric and especially asymmetric stiffness distribution. The asymmetric stiffness perturbation is mentioned in [3] within the robust flutter analysis for aeroelastic systems as an important issue for future investigations. It is quite possible that poor levels of precision with respect to manufacturing capabilities a small difference of bending and/or torsional stiffness may occur between the two wing structures which -in worst-case scenario- can be significant enough to cause an unpredictable coupling between symmetric and asymmetric modes. Therefore, it is essential to model such an asymmetry by means of an adequate uncertainty in physical stiffness model for each wing separately. * Özge Süelözgen [email protected] 1
German Aerospace Center (DLR), Institute of System Dynamics and Control, 82234 Wessling, Germany
This paper starts with a brief mathematical introduction on the LFT representation of uncertain systems and provides an understanding of the definition and interpretation of 𝜇 within the robust stability analysis.
2 Linear fractional transformation and ‑analysis The linear fractional transformation is a common framework for robust stability analysis of complex systems based on the small
Data Loading...
