The Experts below are selected from a list of 7278 Experts worldwide ranked by ideXlab platform

Rob Hewson - One of the best experts on this subject based on the ideXlab platform.

  • Composite stacking sequence optimization for aeroelastically tailored forward-swept Wings
    Structural and Multidisciplinary Optimization, 2017
    Co-Authors: Christopher Bach, Reda Jebari, Andrea Viti, Rob Hewson
    Abstract:

    A method for stacking sequence optimization and aeroelastic tailoring of forward-swept composite Wings is presented. It exploits bend-twist coupling to mitigate aeroelastic divergence. The method proposed here is intended for estimating potential weight savings during the preliminary aircraft design stages. A structural beam model of the composite Wingbox is derived from anisotropic shell theory and the governing aeroelastic equations are presented for a spanwise discretized forward swept Wing. Optimization of the system to reduce Wing mass is undertaken for sweep angles of −35° to 0° and Mach numbers from 0.7 to 0.9. A subset of lamination parameters (LPs) and the number of laminate plies in each pre-defined direction (restricted to {0°,±45°, 90°}) serve as design variables. A bi-level hybrid optimization approach is employed, making use of a genetic algorithm (GA) and a subsequent gradient-based optimizer. Constraints are implemented to match lift requirements and prevent aeroelastic divergence, excessive deformations, airfoil stalling and structural failure. A permutation GA is then used to match specific composite ply stacking sequences to the optimum design variables with a limited number of manufacturing constraints considered for demonstration purposes. The optimization results in positive bend-twist coupling and a reduced structural mass. Results are compared to an uncoupled Reference Wing with quasi-isotropic layups and with panel thickness alone the design variables. For a typical geometry and a forward sweep of −25° at Mach 0.7, a Wingbox mass reduction of 13 % was achieved.

Michael B. Bragg - One of the best experts on this subject based on the ideXlab platform.

  • Large-Scale Swept-Wing Icing Simulations in the NASA Glenn Icing Research Tunnel Using LEWICE3D
    6th AIAA Atmospheric and Space Environments Conference, 2014
    Co-Authors: Brock D. Wiberg, Gustavo E. C. Fujiwara, Brian S. Woodard, Michael B. Bragg
    Abstract:

    Computational icing simulations of a hybrid, swept-Wing model in the NASA IRT are presented. The results of these simulations are compared to those for the same icing conditions conducted on the full-scale Reference Wing. The effects of tunnel sidewalls, attachment line position, and altitude are considered. A discussion of icing scaling and the results of one scaling approach are given. The variation of impingement and ice shape with span in the tunnel for different angles of attack and flap deflection are presented.

  • Swept-Wing Ice Accretion Characterization and Aerodynamics
    5th AIAA Atmospheric and Space Environments Conference, 2013
    Co-Authors: Andy P. Broeren, Mark G. Potapczuk, James T. Riley, Philippe Villedieu, Frédéric Moens, Michael B. Bragg
    Abstract:

    NASA, FAA, ONERA, the University of Illinois and Boeing have embarked on a significant, collaborative research effort to address the technical challenges associated with icing on large-scale, three-dimensional swept Wings. The overall goal is to improve the fidelity of experimental and computational simulation methods for swept-Wing ice accretion formation and resulting aerodynamic effect. A seven-phase research effort has been designed that incorporates ice-accretion and aerodynamic experiments and computational simulations. As the baseline, full-scale, swept-Wing-Reference geometry, this research will utilize the 65 percent scale Common Research Model configuration. Ice-accretion testing will be conducted in the NASA Icing Research Tunnel for three hybrid swept-Wing models representing the 20, 64 and 83 percent semispan stations of the baseline-Reference Wing. Threedimensional measurement techniques are being developed and validated to document the experimental ice-accretion geometries. Artificial ice shapes of varying geometric fidelity will be developed for aerodynamic testing over a large Reynolds number range in the ONERA F1 pressurized wind tunnel and in a smaller-scale atmospheric wind tunnel. Concurrent research will be conducted to explore and further develop the use of computational simulation tools for ice accretion and aerodynamics on swept Wings. The combined results of this research effort will result in an improved understanding of the ice formation and aerodynamic effects on swept Wings. The purpose of this paper is to describe this research effort in more detail and report on the current results and status to date.

Christopher Bach - One of the best experts on this subject based on the ideXlab platform.

  • Composite stacking sequence optimization for aeroelastically tailored forward-swept Wings
    Structural and Multidisciplinary Optimization, 2017
    Co-Authors: Christopher Bach, Reda Jebari, Andrea Viti, Rob Hewson
    Abstract:

    A method for stacking sequence optimization and aeroelastic tailoring of forward-swept composite Wings is presented. It exploits bend-twist coupling to mitigate aeroelastic divergence. The method proposed here is intended for estimating potential weight savings during the preliminary aircraft design stages. A structural beam model of the composite Wingbox is derived from anisotropic shell theory and the governing aeroelastic equations are presented for a spanwise discretized forward swept Wing. Optimization of the system to reduce Wing mass is undertaken for sweep angles of −35° to 0° and Mach numbers from 0.7 to 0.9. A subset of lamination parameters (LPs) and the number of laminate plies in each pre-defined direction (restricted to {0°,±45°, 90°}) serve as design variables. A bi-level hybrid optimization approach is employed, making use of a genetic algorithm (GA) and a subsequent gradient-based optimizer. Constraints are implemented to match lift requirements and prevent aeroelastic divergence, excessive deformations, airfoil stalling and structural failure. A permutation GA is then used to match specific composite ply stacking sequences to the optimum design variables with a limited number of manufacturing constraints considered for demonstration purposes. The optimization results in positive bend-twist coupling and a reduced structural mass. Results are compared to an uncoupled Reference Wing with quasi-isotropic layups and with panel thickness alone the design variables. For a typical geometry and a forward sweep of −25° at Mach 0.7, a Wingbox mass reduction of 13 % was achieved.

Paul Walsh - One of the best experts on this subject based on the ideXlab platform.

  • discretization method for the development of a modular morphing Wing
    Journal of Aircraft, 2012
    Co-Authors: Allan Daniel Finistauri, X I Fengfeng, Paul Walsh
    Abstract:

    This paper presents a discretization method for the development of a modular morphing Wing. The proposed method determines the number of morphing Wing modules and the respective spacing required to emulate a known Wing shape and satisfy a corresponding flight requirement. This method consists of two steps. The first step is geometry discretization. In this step, curvature and twist distribution from the Reference Wing shape quarter chord line are extracted and used to determine the spacing of the discretized Wing modules. This is achieved by clustering moretightlyspacedmorphingWingmodulesinareasoflargetotalcurvature,andfewerlongerWingmodulesinareas of small total curvature. By doing so, geometric congruency between the Reference and discretized Wings is maintained.Thesecondstepisperformanceevaluation.Inthisstep,anaerodynamicperformanceindex(suchasthe lift-to-drag ratio) for a given flight regime is used to evaluate the effectiveness of each modular morphing Wing configuration.OptimalmorphingWingmodulesaredetermineduntilanacceptable flightperformanceisachievedby thediscretizedWing.Theeffectivenessoftheproposeddiscretizationalgorithmisdemonstratedthroughacasestudy by determining an optimal number of modules for a modular morphing Wing.

  • Wing Line Discretization for the Development of a Modular Morphing Wing
    52nd AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference, 2011
    Co-Authors: Paul Walsh, Kamran Behdinan
    Abstract:

    This paper presents a discretization method for the development of a modular morphing Wing. The proposed method determines the number of morphing Wing modules and their respective spacing required to emulate a known Wing shape associated with a particular flight regime/requirement. This method consists of two main steps. The first step is geometry discretization. In this step, curvature and twist distribution from the Reference Wing quarter chord line are extracted and used to determine the spacing of the discretized Wing modules. This is achieved by clustering more, tightly spaced morphing Wing modules in areas of large total curvature, and fewer, longer Wing modules in areas of small total curvature. By doing so, geometric congruency between the Reference and discretized Wings is maintained. The second step is for performance evaluation. In this step, an aerodynamic performance index, like the lift-to-drag ratio, for a given flight regime is used to evaluate the effectiveness of each modular morphing Wing configuration. Morphing Wing modules are sequentially added until an acceptable flight performance is achieved by the discretized Wing. The effectiveness of the proposed discretization algorithm is demonstrated through a case study by determining an optimal number of modules for a modular morphing Wing.

R. De Breuker - One of the best experts on this subject based on the ideXlab platform.

  • FLEXOP – Application of aeroelastic tailoring to a flying demonstrator Wing
    2018
    Co-Authors: Muhammad Yasser Meddaikar, Jurij Sodja, Johannes Dillinger, R. De Breuker
    Abstract:

    This paper presents the application of aeroelastic tailoring in the Wing design of a flying demonstrator. The work is part of the Flutter Free Flight Envelope eXpansion (FLEXOP) project, funded under the Horizon 2020 framework. The project involves the design, manufacturing and flight-testing of a UAV toward two principle goals: i) to demonstrate the passive load alleviation potential through composite tailoring, ii) to validate methods and tools for flutter modelling and flutter control. The work presented here addresses the first of the above mentioned goals. The design of the primary load-carrying Wing-box in this task is performed using a joint DLR – TU Delft optimization strategy. In total, two sets of Wings are designed in order to demonstrate the potential benefits of aeroelastic tailoring – i) a Reference Wing wherein the laminates of the Wing-box members are restricted to balanced and symmetric laminates; ii) a tailored Wing wherein the laminates are allowed to be unbalanced, hence alloWing for the shear-extension and bending-torsion couplings essential for aeroelastic tailoring. The optimized design is then manufactured and extensively tested to validate and improve the simulation models corresponding to the Wing design. Flight tests are scheduled to be performed in late 2018 to demonstrate the load alleviation capabilities attained through the applied aeroelastic tailoring.

  • Design of a flying demonstrator Wing for manoeuvre load alleviation with cruise shape constraint
    2018 AIAA ASCE AHS ASC Structures Structural Dynamics and Materials Conference, 2018
    Co-Authors: Jurij Sodja, N.p.m. Werter, R. De Breuker
    Abstract:

    Application of the aeroelastic framework developed at Delft University of Technology to a design of the tailored composite Wing for a flying demonstrator is presented in this paper. In the design process the structural mass of the Wing is minimised including a cruise shape constraint. Introduction of the cruise shape constraint is explained as well as a number of other important design requirements which were imposed in order to obtain a feasible and flight worthy design. The effect of the cruise shape constraint is investigated by performing a comparison study. For this purpose two Wing types were defined: the Reference Wing and the tailored Wing. The difference between the two Wings is in the laminate definition comprising each Wing. The Reference Wing was designed with symmetric-balanced laminates, while symmetric-only laminates were used for the tailored Wing. The comparison was performed in terms of laminate stiffness and thickness distribution along the span, jig twist, and the aeroelastic response. Elastic deformations, aerodynamic load distribution and Wing root loads are compared within the scope of aeroelastic response.