The need for weight-optimised aerospace structures results in flexible structures with highly nonlinear behaviour. Their control presents challenges that require control theory be developed in order to enable the trend toward lighter structures to continue. Two classes of problem of particular interest in control are systems with a high degree of nonlinearity inherent in the structure and those...

A computational method for accurately predicting the static aeroelastic deformations of typical transonic transport wind tunnel models is described. The method utilizes a finite element method (FEM) for predicting the deformations. Extensive calibratiodvalidation of this method was carried out using a novel wind-off wind tunnel model static loading experiment and wind-on optical wing twist meas...

Level-set topology optimization is used to design a wing considering skin buckling under static aeroelastic trim loading, as well as dynamic aeroelastic stability (flutter). The level-set function is defined over the entire 3D volume of a transport aircraft wing box. Therefore, the approach is not limited by any predefined structure and can explore novel configurations. The Sequential Linear Pr...

Freeplay is one of the most important nonlinearities that affect the control surfaces of the aircraft; it can induce flutter phenomena and limit the performances of the same airplane. To investigate the effect of control surface freeplay, an aeroelastic wind tunnel model of a T-tail has been developed. A variable amplitude freeplay has been introduced in the control chain by a specifically desi...

torsion and infarction of the greater omentum are two rare clinical situations which present as an acute abdomen. nevertheless, knowledge concerning these two problems can help the surgeon in proper diagnosis and treatment. since the first report on primary torsion by eitel in 1899, a few hundred more have been reported and some collective reviews published to date. in this study we will presen...

The market of solar-powered Unmanned Aerial Vehicles (UAVs) for defence purposes and drone services is expected to grow by a factor more than 2 in the next decade. From an aircraft design perspective, main challenge scalability proposed architectures, which needed increase payload capabilities. Beside some successful examples wing-tail UAVs, newcomers are developing prototypes with tandem-wing ...

Background The aim of this study was to determine oxidative stress (OS) parameters after testicular torsion/detorsion in adult rats. MaterialsAndMethods In this experimental study, male adult Wistar rats were divided into four groups, each consisting of seven animals: group I-one hour right testicular torsion with subsequent orchiectomy, group II-one hour right testicular torsion followed by de...

The investigation of flutter and aeroservoelastic stability through flight testing is an essential part of aircraft certification. The stability boundary prediction is especially difficult when the instability is associated with nonlinearity in the dynamics. This paper presents an approach for the characterization of the nonlinear dynamics by non-iterative identification algorithms. Two differe...