The Experts below are selected from a list of 21819 Experts worldwide ranked by ideXlab platform

Gaëtan Kerschen - One of the best experts on this subject based on the ideXlab platform.

  • Complex dynamics of a nonlinear Aerospace Structure: numerical continuation and normal modes
    Nonlinear Dynamics, 2015
    Co-Authors: Luc Renson, J. P. Noël, Gaëtan Kerschen
    Abstract:

    This paper investigates the dynamics of a real-life Aerospace Structure possessing a strongly nonlinear component with multiple mechanical stops. A full-scale finite element model is built for gaining additional insight into the nonlinear dynamics that was observed experimentally, but also for uncovering additional nonlinear phenomena, such as quasiperiodic regimes of motion. Forced/unforced, damped/undamped numerical simulations are carried out using advanced techniques and theoretical concepts such as numerical continuation and nonlinear normal modes.

  • complex dynamics of a nonlinear Aerospace Structure experimental identification and modal interactions
    Journal of Sound and Vibration, 2014
    Co-Authors: Jeanphilippe Noel, Luc Renson, Gaëtan Kerschen
    Abstract:

    Abstract Nonlinear system identification is a challenging task in view of the complexity and wide variety of nonlinear phenomena. The present paper addresses the identification of a real-life Aerospace Structure possessing a strongly nonlinear component with multiple mechanical stops. The complete identification procedure, from nonlinearity detection and characterization to parameter estimation, is carried out based upon experimental data. The combined use of various analysis techniques, such as the wavelet transform and the restoring force surface method, brings different perspectives to the dynamics. Specifically, the Structure is shown to exhibit particularly interesting nonlinear behaviors, including jumps, modal interactions, force relaxation and chattering during impacts on the mechanical stops.

  • a stochastic framework for subspace identification of a strongly nonlinear Aerospace Structure
    2014
    Co-Authors: Jeanphilippe Noel, Johan Schoukens, Gaëtan Kerschen
    Abstract:

    The present study exploits the maximum likelihood identification framework for deriving statistically-optimal models of nonlinear mechanical systems. The identification problem is formulated in the frequency domain, and model parameters are calculated by minimising a weighted least-squares cost function. Initial values of the model parameters are obtained by means of a nonlinear subspace algorithm. The complete identification methodology is first demonstrated on a Duffing oscillator, prior to being applied to a full-scale Aerospace Structure.

Luc Renson - One of the best experts on this subject based on the ideXlab platform.

  • Complex dynamics of a nonlinear Aerospace Structure: numerical continuation and normal modes
    Nonlinear Dynamics, 2015
    Co-Authors: Luc Renson, J. P. Noël, Gaëtan Kerschen
    Abstract:

    This paper investigates the dynamics of a real-life Aerospace Structure possessing a strongly nonlinear component with multiple mechanical stops. A full-scale finite element model is built for gaining additional insight into the nonlinear dynamics that was observed experimentally, but also for uncovering additional nonlinear phenomena, such as quasiperiodic regimes of motion. Forced/unforced, damped/undamped numerical simulations are carried out using advanced techniques and theoretical concepts such as numerical continuation and nonlinear normal modes.

  • complex dynamics of a nonlinear Aerospace Structure experimental identification and modal interactions
    Journal of Sound and Vibration, 2014
    Co-Authors: Jeanphilippe Noel, Luc Renson, Gaëtan Kerschen
    Abstract:

    Abstract Nonlinear system identification is a challenging task in view of the complexity and wide variety of nonlinear phenomena. The present paper addresses the identification of a real-life Aerospace Structure possessing a strongly nonlinear component with multiple mechanical stops. The complete identification procedure, from nonlinearity detection and characterization to parameter estimation, is carried out based upon experimental data. The combined use of various analysis techniques, such as the wavelet transform and the restoring force surface method, brings different perspectives to the dynamics. Specifically, the Structure is shown to exhibit particularly interesting nonlinear behaviors, including jumps, modal interactions, force relaxation and chattering during impacts on the mechanical stops.

Martin A. Ferman - One of the best experts on this subject based on the ideXlab platform.

  • Static Feedback Control Augmented with an Adaptive Neural Network Applied to an Aerospace Structure
    2007 American Control Conference, 2007
    Co-Authors: Kenneth R. Buckholtz, Kevin A. Wise, Martin A. Ferman
    Abstract:

    For the purpose of controlling an Aerospace Structure, this paper discusses a controller architecture which is comprised of a static gain feedback controller, augmented with a neural network adaptive controller. A typical approach to constructing an Aerospace system controller is to schedule a set of static gains, depending upon selective operating conditions. A shortcoming of this approach is ensuring robustness across the entire operating envelope and to uncertainties in the system. To overcome this issue, an adaptive controller is incorporated into the architecture. The adaptive controller acts to improve the rapidity and robustness of the static gain feedback controller. This architecture is applied to suppressing unstable wing oscillations, and demonstrated through Monte Carlo analysis.

Gabriele Fabbi - One of the best experts on this subject based on the ideXlab platform.

  • theoretical and numerical approaches for impact load identification on an Aerospace Structure correlation with experimental data
    53rd AIAA Aerospace Sciences Meeting, 2015
    Co-Authors: Gabriele Fabbi
    Abstract:

    An inverse problem procedure to identify the impact position and force on an Aerospace Structure, given the experimental data related to the phenomenon, is presented. The test case is a real-life engineering problem, namely a shock anomaly on the VEGA launcher first stage nozzle, as measured in the acceleration time histories during its first flight. After a time-domain description of the experimental data and an energy distribution investigation via POD approach, the core procedure is presented. This is composed of three steps. Firstly, an acceleration signal energy sensitivity analysis with respect to the load identifies the most suitable impact positions. Secondly, an optimization process estimates the force and the approximate impact location by correlating the above mentioned signal energies to their corresponding experimental values. Finally, an explicit nonlinear dynamic solver is involved for validation by correlating its numerical results with the actual data in terms of global features (signal energies, vibration maxima, and decay times). The satisfactory outcome of this step would also confirm the impacting body supposed physical nature.

Eduardo Barrera Lopez De Turiso - One of the best experts on this subject based on the ideXlab platform.

  • integrated phased array transducer for on board structural health monitoring
    Structural health monitoring 2012 : proceedings of the Sixth European Workshop on Structural Health Monitoring held at Dresdren Germany July 3-6 2012 , 2012
    Co-Authors: Mariano González, Valerijan Cokonaj, Simone Corbò, Alejandro Alcaide, Gerardo Aranguren, Luciano Casado, Antonio Cano, Eduardo Barrera Lopez De Turiso
    Abstract:

    Permanently bonded onto a Structure, an integrated Phased Array (PhA II) transducer that can provide reliable electromechanical connection with corresponding sophisticated miniaturized ?all in one? SHM electronic device installed directly above it, without need for any interface cabling, during all Aerospace Structure lifecycle phases and for a huge variety of real harsh service environments of Structures to be monitored is presented. This integrated PhA II transducer [1], as a key component of the PAMELA SHM? (Phased Array Monitoring for Enhanced Life Assessment) system, has two principal tasks at the same time, reliably transceive elastic waves in real Aerospace service environments and serves as a reliable sole carrier or support for associated integrated on-board SHM electronic device attached above. The PhA II transducer successfully accomplished both required task throughout extensive test campaigns which included low to high temperature tests, temperature cycling, mechanical loading, combined thermo- mechanical loading and vibration resistance, etc. both with and without SHM device attached above due to RTCA DO-160F.

  • integrated phased array transducer for on board structural health monitoring
    Structural health monitoring 2012 : proceedings of the Sixth European Workshop on Structural Health Monitoring held at Dresdren Germany July 3-6 2012 , 2012
    Co-Authors: Mariano González, Valerijan Cokonaj, Simone Corbò, Alejandro Alcaide, Gerardo Aranguren, Luciano Casado, Antonio Cano, Eduardo Barrera Lopez De Turiso
    Abstract:

    Permanently bonded onto a Structure, an integrated Phased Array (PhA II) transducer that can provide reliable electromechanical connection with corresponding sophisticated miniaturized ?all in one? SHM electronic device installed directly above it, without need for any interface cabling, during all Aerospace Structure lifecycle phases and for a huge variety of real harsh service environments of Structures to be monitored is presented. This integrated PhA II transducer [1], as a key component of the PAMELA SHM? (Phased Array Monitoring for Enhanced Life Assessment) system, has two principal tasks at the same time, reliably transceive elastic waves in real Aerospace service environments and serves as a reliable sole carrier or support for associated integrated on-board SHM electronic device attached above. The PhA II transducer successfully accomplished both required task throughout extensive test campaigns which included low to high temperature tests, temperature cycling, mechanical loading, combined thermo- mechanical loading and vibration resistance, etc. both with and without SHM device attached above due to RTCA DO-160F.