System identification is evaluated as an efficient and accurate technique for modeling unsteady aerodynamic forces for use in time-domain aeroelastic analysis. In the system identification methodology, the constant coefficients of a linear system model are fit to the computed response time histories from a 3-D, unsteady CFD solver. The resulting model of the unsteady CFD solution is independent...

Significant developments in bridge aeroelastic analysis have been made utilizing realistic aerodynamic force modeling for bridges with bluff sections under turbulent winds. With these developments as a background, this paper highlights state-of-the-art developments in the aeroelastic analysis and identifies new frontiers in aerodynamic tailoring of long span bridges. Challenges in the aeroelast...

The Active Vibration and Noise Reduction (AVINOR) aeroelastic simulation code for helicopter rotor blades is described. AVINOR is a research code that has been developed at UCLA and the University of Michigan for the purpose of conducting computationally efficient aeroelastic response analyses while maintaining a level of fidelity so as to be suitable for preliminary design of helicopter rotor ...

Abstract: This paper presents a case study how to apply the recently proposed TP model transformation technique, that has been introduced for nonlinear statefeedback control design, to nonlinear observer design. The study is conducted through an example. This example treats the question of observer design to the prototypical aeroelastic wing section with structural nonlinearity. This type of mo...

Representation and identification of a nonlinear aeroelastic pitch-plunge system as a model of the Nonlinear AutoRegressive, Moving Average eXogenous (NARMAX) class is considered. A nonlinear difference equation describing this aircraft model is derived theoretically and shown to be of the NARMAX form. Identification methods for NARMAX models are applied to aeroelastic dynamics and its properti...

This thesis summarizes investigations performed within design, analysis and experimental evaluation of flexible aircraft structures. Not only the problems, but rather the opportunities related to aeroelasticity are discussed. In the first part of the thesis, different concepts for using active aeroelastic configurations to increase aircraft performance are considered. In particular, one study d...

An investigation of the effects of small mistiming on the aeroelastic modes of bladed-disk assemblies with aerodynamic coupling between blades is presented. The cornerstone of the approach is the use and development of perturbation methods that exhibit the crucial role of the interblade coupling and yield general findings regarding mistuning effects. It is shown that blade assemblies with weak ...

In this paper, a class of multi-input/multi-output aeroelastic systems with unstructured nonlinear uncertainty is considered. By using leadingand trailing-edge control surface actuations, a continuous robust controller is proposed to suppress the aeroelastic vibrations of a nonlinearwing-sectionmodelwith plunging andpitching degrees of freedom. Under amild restriction that the system uncertaint...

This paper presents a parametric study on the aeroelasticity of cantilever wings equipped with Flared Hinge Folding Wingtips (FHFWTs). The finite element method is utilized to develop computational, low-fidelity aeroelastic model. wing structure modelled using Euler–Bernoulli beam elements, and unsteady Theodorsen’s aerodynamic strip Theory used for load predictions. PK estimate boundaries. mod...

Numerical simulation of aircraft’s flutter is rather expensive and time-consuming. In order to save expense and calculating time, we apply first-order approximate conditions to solve the unsteady transonic Euler equations coupled with aeroelastic equations. Assuming that the airfoil is thin and undergoes small deformation, we implement wall boundary conditions on nonmoving mean wall positions. ...