Change search
Refine search result
1 - 14 of 14
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Eller, David
    et al.
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Heinze, Sebastian
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    A computational study on the use of redundant control surfaces to improve the induced drag of aeroelastic configurations2003Report (Other academic)
  • 2.
    Eller, David
    et al.
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Heinze, Sebastian
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    An approach to induced drag reduction and its experimental evaluation2004Conference paper (Refereed)
    Abstract [en]

    An approach to minimize the induced drag of an aeroelastic configuration by means of multiple leading and trailing edge control surfaces is investigated. A computational boundary-element model is constructed and flap settings which reduce the induced drag predicted by the model are found by means of numerical optimization. Further, experiments with an elastic wind tunnel model are performed, showing both the potential for drag reduction and weaknesses of the simulation method employed.

  • 3.
    Eller, David
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Heinze, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Approach to Induced Drag Reduction with Experimental Evaluation2005In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 42, no 6, p. 1478-1485Article in journal (Refereed)
    Abstract [en]

    An approach to minimize the induced drag of an aeroelastic configuration by means of multiple leading- and trailing-edge control surfaces is investigated. A computational model based on a boundary-element method is constructed and drag-reducing flap settings are found by means of numerical optimization. Further, experiments with an elastic wind-tunnel model are performed in order to evaluate the numerically obtained results. Induced-drag results are obtained by analyzing lift distributions computed from optically measured local angles of attack because standard techniques proved insufficient. Results show that significant reductions of induced drag of flexible wings can be achieved by using optimal control surface settings.

  • 4.
    Heinze, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Aeroelastic Concepts for Flexible Aircraft Structures2007Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    In this thesis, aeroelastic concepts for increased aircraft performance are developed and evaluated. Active aeroelastic concepts are in focus as well as robust analysis concepts aiming at efficient analysis using numerical models with uncertain or varying model parameters.

    The thesis presents different approaches for exploitation of fluid-structure interaction of active aeroelastic structures. First, a high aspect ratio wing in wind tunnel testing conditions is considered. The wing was developed within the European research project \textit{Active Aeroelastic Aircraft Structures} and used to demonstrate how structural flexibility can be exploited by using multiple control surfaces such that the deformed wing shape gives minimum drag for different flight conditions. Two different drag minimization studies are presented, one aiming at reduced induced drag based on numerical optimization techniques, another one aiming at reduced measured total drag using real-time optimization in the wind tunnel experiment. The same wing is also used for demonstration of an active concept for gust load alleviation using a piezoelectric tab. In all studies on the high aspect ratio wing, it is demonstrated that structural flexibility can be exploited to increase aircraft performance.

    Other studies in this thesis investigate the applicability of robust control tools for flutter analysis considering model uncertainty and variation. First, different techniques for taking large structural variations into account are evaluated. Next, a high-fidelity numerical model of an aircraft with a variable amount of fuel is considered, and robust analysis is applied to find the worst-case fuel configuration. Finally, a study investigating the influence of uncertain external stores aerodynamics is presented. Overall, the robust approach is shown to be capable of treating large structural variations as well as modeling uncertainties to compute worst-case configurations and flutter boundaries.

  • 5.
    Heinze, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Aeroelastic Concepts for Flexible Wing Structures2005Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    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 deals with the minimization of the induced drag of a highly flexible wing by using multiple control surfaces. Another study deals with a possible implementation of a high-bandwidth piezo electric actuator for control applications using aeroelastic amplification.

    The second part of the thesis deals with the development of an approach for modeling and analysis of flexible structures considering uncertainties in analysis models. Especially in cases of large structural variations, such as fuel level variations, a fixed-base modal formulation in robust flutter analysis may lead to incorrect results. Besides a discussion about this issue, possible means of treating this problem are presented.

  • 6.
    Heinze, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Assessment of critical fuel configurations using robust flutter analysis2006Conference paper (Refereed)
    Abstract [en]

    An approach to assess critical fuel configurations using robust flutter analysis is presented. A realistic aircraft model is considered to demonstrate how an available finite element model can be adapted to easily apply robust flutter analysis with respect to structural variations, such as fuel level variations. The study shows that standard analysis tools can be used to efficiently generate the system data that is required to perform robust flutter analysis. The μ-k method is used to compute the worst-case flutter speed and the corresponding worst-case fuel configuration is found. The main advantage of the proposed approach is that μ analysis guarantees robustness with respect to all possible fuel configurations represented by the tank model.

  • 7.
    Heinze, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Assessment of Critical Fuel Configurations Using Robust Flutter Analysis2007In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 44, no 6, p. 2034-2039Article in journal (Refereed)
    Abstract [en]

    An approach to assess critical fuel configurations using robust flutter analysis is presented. A realistic aircraft model is considered to demonstrate how an available finite element model can be adapted to easily apply robust flutter analysis with respect to structural variations such as fuel-level variations. The study shows that standard analysis tools can be used to efficiently generate the system data that are required to perform robust flutter analysis. The μ-k method is used to compute the worst-case flutter speed, and the corresponding worst-case fuel configuration is found. The main advantage of the proposed approach is that μ. analysis guarantees robustness with respect to all possible fuel configurations represented by the tank model.

  • 8.
    Heinze, Sebastian
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Borglund, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    On the influence of modeshape variations in robust flutter analysis2005Report (Other academic)
  • 9.
    Heinze, Sebastian
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Borglund, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Robust Flutter Analysis Considering Mode Shape Variations2008In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 45, no 3, p. 1070-1074Article in journal (Refereed)
    Abstract [en]

    A study was conducted to perform robust flutter analysis, considering mode shape variation problems. The study demonstrated that the assumption of a fixed modal base can lead to incorrect flutter results. It was demonstrated the nominal model can act as the basis for performing robust flutter analysis. The study assumed that the critical flutter mode shape can be represented by a linear combination of eigenmodes. The study also demonstrated that the modal base method can be used, to solve the problem of mode shape variations. It was also demonstrated that results of mode shape variation problems can be improved significantly, by adding structural eigenvectors.

  • 10.
    Heinze, Sebastian
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Karpel, Moti
    Technion - Israel Institute of Technology.
    Analysis and Wind Tunnel Testing of a Piezoelectric Tab for Aeroelastic Control Applications2006In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 43, no 6, p. 1799-1804Article in journal (Refereed)
    Abstract [en]

    A concept for exploitation of a piezoelectric actuator by using aeroelastic amplification is presented. The approach is to use the actuator for excitation of a tab that occupies the rear 25 % of a free-floating trailing edge flap. A flexible high aspect ratio wing wind tunnel model is used as a test case. Wind tunnel experiments were performed to determine frequency response functions for validation of the numerical model used for the control law design. The aeroservoelastic model is based on state-space equations of motion that accept piezoelectric voltage commands. Control laws are derived for gust alleviation with flutter and control authority constraints, and numerical results that demonstrate a significant reduction in the structural response are presented. Possible applications and feasibility of the concept are discussed.

  • 11.
    Heinze, Sebastian
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Ringertz, Ulf
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Borglund, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Assessment of Uncertain External Store Aerodynamics Using mu -p Flutter Analysis2009In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 46, no 3, p. 1062-1068Article in journal (Refereed)
  • 12.
    Heinze, Sebastian
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Ringertz, Ulf
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Borglund, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    On the Uncertainty Modeling for External Stores AerodynamicsManuscript (Other academic)
    Abstract [en]

    A wind tunnel model representing a generic delta wing configurationwith external stores is considered for flutter investigations. Complexeigenvalues are estimated for the wind tunnel model for airspeeds up tothe flutter limit, and compared to eigenvalues predicted by a numericalmodel. The impact of external stores mounted to the wing tip is investigatedboth experimentally and numerically, and besides the impact of thestores as such, the capability of the numerical model to account for increasingmodel complexity is investigated. An uncertainty approach basedon robust flutter analysis is demonstrated to account for modeling imperfections.Uncertainty modeling issues and the reliability of uncertaintymodels are discussed. Provided that the present uncertainty mechanismcan be determined, it is found that available uncertainty tools may beused to efficiently compute robust flutter boundaries.

  • 13.
    Heinze, Sebastian
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Ringertz, Ulf
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Borglund, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    On Uncertainty Modeling and Validation for External Store Aerodynamics2007In: IFASD 2007: International Forum on Aeroelasticity and Structural Dynamics, 2007Conference paper (Other academic)
  • 14.
    Jacobsen, Marianne
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Heinze, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Drag Minimization of an Active Flexible Wing with Multiple Control SurfacesArticle in journal (Other academic)
    Abstract [en]

    In this study, the performance of a highly flexible wing with multiplecontrol surfaces is optimized for different flight conditions. A windtunnel model with 20 independent control surfaces is used as the testobject. The problem is posed as a nonlinear optimization problem withthe measured drag as the objective. Constraints include keeping the liftconstant, as well as having bounds on the control surface deflections. Nocomputational estimation of the drag is performed. Instead, experimentalmeasurements of the drag are used to perform the optimization in realtime using a generating set search method (GSS). The algorithm makesthe wing adapt to the current flight condition to improve performanceand the experimental evaluation of the method shows that the drag issignificantly reduced within a wide range of flight conditions. A study onthe number of control surfaces needed is also included, and the resultsshow that, if chosen properly, only three control surfaces distributed overthe wing are needed to reduce drag significantly.

1 - 14 of 14
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf