Effect of Transport Aircraft Wing Loads Spectrum Variation on Crack Growth

2009 ◽  
pp. 143-143-27 ◽  
Author(s):  
PR Abelkis
Keyword(s):  
Crack Growth ◽  
Aircraft Wing ◽  
Transport Aircraft

Conceptual Design Optimization With Economic Uncertainty: An Application to Interactions Between Designers and Airlines

2014 ◽  
Author(s):  
Garrett Waycaster ◽  
Christian Bes ◽  
Volodymyr Bilotkach ◽  
Christian Gogu ◽  
Raphael Haftka ◽  
...  
Keyword(s):  
Asymmetric Information ◽  
Design Optimization ◽  
Operating Costs ◽  
Economic Uncertainty ◽  
Aircraft Wing ◽  
Design Decisions ◽  
Transport Aircraft ◽  
Sources Of Uncertainty ◽  
Optimal Decisions ◽  
Engineering Problems

Many engineering problems involve interactions between multiple decisions makers, or stakeholders, each with their own objectives and uncertainties. Considering these interactions during design optimization allows us to account for new sources of uncertainty, which we refer to as economic uncertainty. In this paper, we consider an application of optimization considering interactions between aircraft designers and airlines based on the design of a commercial transport aircraft wing. We consider that the aircraft designer makes their design decisions first, and therefore must predict the reaction of the airline. We focus on the effect of two economic uncertainties: uncertainty that would normally only affect the airline and uncertainty due to asymmetric information, or errors in the designers’ understanding of the airlines’ preferences. We find that these uncertainties play a significant role in the optimal decisions by both airlines and designers. We also show that asymmetric information may actually be beneficial for both stakeholders in certain cases, where both players benefit from the aircraft designer underestimating the operating costs of the airline.

Fatigue Crack Growth of LC9 Aluminum Alloy under Flying Loading with Corrosion Damage

2014 ◽  
Vol 488-489 ◽  
pp. 66-69
Author(s):  
Xu Dong Li ◽  
Zeng Jie Cai ◽  
Zhi Tao Mu
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Cracks ◽  
Corrosion Damage ◽  
Growth Behavior ◽  
Transport Aircraft ◽  
Suitable Parameter ◽  
Corrosion Pits

This paper investigates the growth behavior of fatigue cracks initiated at corrosion pits in laboratory coupons of LC9 aluminum alloy subjected to a transport aircraft loading spectrum. Corrosion pits were introduced by exposing the coupons to EXCO solution for a variety of periods to produce corrosion damage varying from mild to severe. In general, the presence of corrosion damage reduced the fatigue lives of components to a severe extent. It was found that the depth of the corrosion pit was a suitable parameter for characterizing the corrosion damage and for predicting the fatigue life of the coupons using commercial fatigue crack growth software

A case for multi-level optimisation in aeronautical design

1999 ◽  
Vol 103 (1028) ◽  
pp. 481-485 ◽  
Author(s):  
G. M. Robinson ◽  
A. J. Keane
Keyword(s):  
Computational Cost ◽  
Design Tool ◽  
Test Bed ◽  
Design Environment ◽  
Aircraft Wing ◽  
Computing Power ◽  
Transport Aircraft ◽  
Estimation Algorithms ◽  
Multi Level ◽  
Optimisation Algorithms

Abstract This paper discusses how the inevitable limitations of computing power available to designers has restricted adoption of optimisation as an essential design tool. It is argued that this situation will continue until optimisation algorithms are developed which utilise the range of available analysis methods in a manner more like human designers. The concept of multi-level algorithms is introduced and a case made for their adoption as the way forward. The issues to be addressed in the development of multi-level algorithms are highlighted. The paper goes on to discuss a system developed at Southampton University to act as a test bed for multi-level algorithms deployed on a realistic design task. The Southampton University multi-level wing design environment integrates drag estimation algorithms ranging from an empirical code to an Euler CFD code, covering a 150,000 fold difference in computational cost. A simple multi-level optimisation of a civil transport aircraft wing is presented.

scholarly journals Numerical Computation of Subsonic Oscillatory Airforce Coefficients for Wing-Winglet Configurations

2007 ◽  
Vol 1 (3) ◽  
pp. 303-328
Author(s):  
C.W. Cheung
Keyword(s):  
Computer Program ◽  
Theoretical Development ◽  
Dihedral Angles ◽  
Aircraft Wing ◽  
Lattice Method ◽  
Surface Theory ◽  
Transport Aircraft ◽  
Harmonic Motion ◽  
Doublet Lattice Method ◽  
Stiffness And Damping

This paper presents the theoretical development and numerical results of a lifting-surface theory for calculating oscillating airforce coefficients for wing-winglet configurations and it follows the author's previous paper on the extension of Davies' T-tail theory for cruciform-tail configurations. The wing-winglet configurations are assumed to vibrate in a simple harmonic motion of infinitesimal amplitude in a subsonic airstream such that linearised aerodynamic theory is applicable for the analysis of the motion. The modes of displacement of the wing-winglet configuration may be either symmetric or antisysmmetric with respect to the centre-line of the configuration in the direction of the flow. A computer program has been developed for the evaluation of oscillatory airforce coefficients for wing-winglet configurations. Aerodynamic stiffness and damping matrices which are normally used for aeroelastic calculations have been obtained for a typical transport aircraft wing-winglet configuration at two winglet dihedral angles and comparisons have been made against those calculated by an alternative doublet-lattice method. The comparisons have been shown to be satisfactory.

Sign in / Sign up

Export Citation Format

Share Document