Rapid Prediction of Worst Case Gust Loads Following Structural Modification

2012 ◽  
Author(s):  
Hamed Khodaparast ◽  
Jonathan Cooper
Keyword(s):  
Structural Modification ◽  
Worst Case ◽  
Rapid Prediction ◽  
Gust Loads

Rapid Prediction of Worst-Case Gust Loads Following Structural Modification

AIAA Journal ◽  
2014 ◽  
Vol 52 (2) ◽  
pp. 242-254 ◽  
Author(s):  
H. Haddad Khodaparast ◽  
J. E. Cooper
Keyword(s):  
Structural Modification ◽  
Worst Case ◽  
Rapid Prediction ◽  
Gust Loads

Rapid Prediction of Worst Case Gust Loads

2011 ◽  
Author(s):  
Jonathan Cooper ◽  
H. Khodaparast ◽  
Sergio Ricci ◽  
G. Georgiou ◽  
Gareth Vio ◽  
...  
Keyword(s):  
Worst Case ◽  
Rapid Prediction ◽  
Gust Loads

Efficient Determination of Worst-Case Gust Loads Using System Norms

2017 ◽  
Vol 54 (3) ◽  
pp. 1205-1210 ◽  
Author(s):  
Andreas Knoblach ◽  
Gertjan Looye
Keyword(s):  
Worst Case ◽  
Gust Loads

scholarly journals The effect of folding wingtips on the worst-case gust loads of a simplified aircraft model

2021 ◽  
pp. 095441002110109
Author(s):  
Davide Balatti ◽  
Hamed Haddad Khodaparast ◽  
Michael I Friswell ◽  
Marinos Manolesos ◽  
Mohammadreza Amoozgar
Keyword(s):  
Safety Margin ◽  
Load Prediction ◽  
Worst Case ◽  
Flutter Speed ◽  
Numerical Studies ◽  
Aeroelastic Model ◽  
Aircraft Performance ◽  
Gust Loads ◽  
Hinge Position ◽  
Gust Load Alleviation

In recent years, the development of lighter and more efficient transport aircraft has led to an increased focus on gust load alleviation. A recent strategy is based on the use of folding wingtip devices that increase the aspect ratio and therefore improve the aircraft performance. Moreover, numerical studies have suggested such a folding wingtip solution may incorporate spring devices in order to provide additional gust load alleviation ability in flight. It has been shown that wingtip mass, stiffness connection and hinge orientation are key parameters to avoid flutter and achieve load alleviation during gusts. The objective of this work is to show the effects of aeroelastic hinged wingtip on the problem of worst-case gust prediction and the parameterization and optimization of such a model for this particular problem, that is, worst-case gust load prediction. In this article, a simplified aeroelastic model of full symmetric aircraft with rigid movable wingtips is developed. The effects of hinge position, orientation and spring stiffness are considered in order to evaluate the performance of this technique for gust load alleviation. In addition, the longitudinal flight dynamics of a rigid aircraft with an elastic wing and folding wingtips is studied. Multi-objective optimizations are performed using a genetic algorithm to exploit the optimal combinations of the wingtip parameters that minimize the gust response for the whole flight envelope while keeping flutter speed within the safety margin. Two strategies to increase flutter speed based on the modification of the wingtip parameters are presented.

Worst-case gust loads prediction with the effects of local structural nonlinearity

2019 ◽  
Author(s):  
Lucia Garcia Matas ◽  
Hamed Haddad Khodaparast ◽  
Micheal I. Friswell ◽  
Andrea Castrichini ◽  
Simon Coggon ◽  
...  
Keyword(s):  
Worst Case ◽  
Structural Nonlinearity ◽  
Gust Loads

Determining Worst-Case Gust Loads on Aircraft Structures Using an Evolutionary Algorithm

2004 ◽  
Vol 20 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Charles L. Karr ◽  
Thomas A. Zeiler ◽  
Rajiv Mehrotra
Keyword(s):  
Evolutionary Algorithm ◽  
Worst Case ◽  
Aircraft Structures ◽  
Gust Loads

Cristal-growth dynamics of n-doped gaAs

1992 ◽  
Vol 50 (2) ◽  
pp. 1544-1545
Author(s):  
Pham V. Huong ◽  
Stéphanie Bouchet ◽  
Jean-Claude Launay
Keyword(s):  
Crystal Growth ◽  
Spatial Resolution ◽  
Epitaxial Layer ◽  
Outer Surface ◽  
Gaas Substrate ◽  
Structural Modification ◽  
Growth Dynamics ◽  
Argon Laser ◽  
High Anisotropy ◽  
Crystal Gaas

Microstructure of epitaxial layers of doped GaAs and its crystal growth dynamics on single crystal GaAs substrate were studied by Raman microspectroscopy with a Dilor OMARS instrument equipped with a 1024 photodiode multichannel detector and a ion-argon laser Spectra-Physics emitting at 514.5 nm.The spatial resolution of this technique, less than 1 μm2, allows the recording of Raman spectra at several spots in function of thickness, from the substrate to the outer deposit, including areas around the interface (Fig.l).The high anisotropy of the LO and TO Raman bands is indicative of the orientation of the epitaxial layer as well as of the structural modification in the deposit and in the substrate at the interface.With Sn doped, the epitaxial layer also presents plasmon in Raman scattering. This fact is already very well known, but we additionally observed that its frequency increases with the thickness of the deposit. For a sample with electron density 1020 cm-3, the plasmon L+ appears at 930 and 790 cm-1 near the outer surface.

Sign in / Sign up

Export Citation Format

Share Document