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  • 1.
    de Conchard, Antoine Vermeil
    et al.
    Univ Nantes, Dept Mech Mat & Civil Engn, Ecole Cent Nantes, Nantes, France..
    Mao, Huina
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Rumpler, Romain
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    A perfectly matched layer formulation adapted for fast frequency sweeps of exterior acoustics finite element models2019In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 398, article id UNSP 108878Article in journal (Refereed)
    Abstract [en]

    Effective treatment of unbounded domains using artificial truncating boundaries are essential in numerical simulation, e.g. using the Finite Element Method (FEM). Among these, Perfectly Matched Layers (PML) have proved to be particularly efficient and flexible. However, an efficient handling of frequency sweeps is not trivial with such absorbing layers since the formulation inherently contains coupled space-and frequency-dependent terms. Using the FEM, this may imply generating system matrices at each step of the frequency sweep. In this paper, an approximation is proposed in order to allow for efficient frequency sweeps. The performance and robustness of the proposed approximation is presented on 2D and 3D acoustic cases. A generic, robust way to truncate the acoustic domain efficiently is also proposed, tested on a range of test cases and for different frequency regions. All rights reserved.

  • 2.
    Dowling, Luke
    et al.
    Trinity College Dublin.
    Mao, Huina
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Flanagan, Lara
    Trinity College Dublin.
    Kennedy, John
    Trinity College Dublin.
    Rice, H J
    Trinity College Dublin.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. Siemens Industry Software, Leuven Belgium.
    A combined design-manufacturing-testing investigation of micro- to macro-scale tailoring of open poroelastic materials based on perturbed kelvin cell micro-geometries2018In: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics, 1177 , 2018, p. 1163-1177Conference paper (Refereed)
  • 3.
    Mallol, Pau
    et al.
    KTH. Inkonova AB, Sweden.
    Mao, Huina
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Experiments and simulations of the deployment of a bistable composite boom2018In: Journal of Spacecraft and Rockets, ISSN 0022-4650, E-ISSN 1533-6794, Vol. 55, no 2, p. 292-302Article in journal (Refereed)
    Abstract [en]

    The rapidly growing use of small satellites for space missions requires deployable systems to be highly storable yet large and with adequate mechanical properties when deployed. This paper focuses on the modeling and simulation of a meter-class passively deployable boom, based on the self-contained linear meter-class deployable boom, exploiting the bistable nature of composite shells. Experimental tests were performed on a boom prototype suspended in a gravity offloading system. The strain energy level, deployment time, and spacecraft displacements calculated from the finite element method agree well with analytical analyses, confirming the theoretical accuracy of the finite element method. Because friction and strain energy relaxation were not included in the model, the finite element simulations predicted deployment times up to five times shorter than those of the gravity offloaded boom experiments. The quick deployment and violent end-of-deployment shock created boom deployment dynamics that were not seen in the experiments. The observed differences between the finite element model and the tests were mainly due to inaccurate material and friction models.

  • 4.
    Manzari, Luca
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Mao, Huina
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. Siemens Industry Software, Leuven Belgium.
    Lopez Arteaga, Ines
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Experimental-numerical methods for inverse characterization of the anisotropic-anelastic properties of porous materials, based on dynamic Digital Image Correlation2018In: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics, 2018, p. 687-695Conference paper (Refereed)
    Abstract [en]

    One of the major challenges in accurately modeling poroelastic materials is the choice of the parametersrequired for their modeling, immediately followed by the practical difficulty in obtaining them. The direc-tional dependencies of the physical properties further complicate the task of designing experimental setupscapable of providing the macroscopic properties. In the work presented here, the focus has been set on theacquisition of high quality displacement data by means of two high-speed cameras and 3D Digital ImageCorrelation. The obtained displacement field, is fed into a general inverse formulation which is guided by anoptimization tool that minimizes the difference between the predicted and the measured data. As a minimumis found, the corresponding parameters are interpreted as material properties for a certain physical model.The solutions for each iteration are calculated with numerical prediction tools, in the cases discussed herethe finite element method, where it must be ascertained that the numerical errors are kept to a minimal level

  • 5.
    Mao, Huina
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Numerical and Experimental Studies of Deployment Dynamics of Space Webs and CubeSat Booms2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, experiments and simulations are performed to study the deployment dynamics of space webs and space booms, focusing on the deployment and stabilization phases of the space web and the behavior of the bi-stable tape spring booms after long-term stowage.

    The space web, Suaineadh, was launched onboard the sounding rocket REXUS-12 from the Swedish launch base Esrange in Kiruna on 19 March 2012. It served as a technology demonstrator for a space web. A reaction wheel was used to actively control the deployment and stabilization states of the 2×2 m2 space web. After ejection from the rocket, the web was deployed but entanglements occurred since the web did not start to deploy at the specified angular velocity. The deployment dynamics was reconstructed by simulations from the information recorded by inertial measurement units and cameras. Simulations show that if the web would have started to deploy at the specified angular velocity, the web would most likely have been deployed and stabilized in space by the motor, reaction wheel and controller used in the experiment. A modified control method was developed to stabilize the out-of-plane motions before or during deployment. New web arms with tape springs were proposed to avoid entanglements.

    A deployable booms assembly composed of four 1-m long bi-stable glass fiber tape springs was designed for the electromagnetically clean 3U CubeSat Small Explorer for Advanced Missions (SEAM). The deployment dynamics and reliability of the SEAM boom design after long-term stowage were tested by on-ground experiments. A simple analytical model was developed to predict the deployment dynamics and to assess the effects of the GOLS and the combined effects of friction, viscoelastic strain energy relaxation, and other factors that act to decrease the deployment force. In order to mitigate the viscoelastic effects and thus ensure self-deployment, different tape springs were designed, manufactured and tested. A numerical model was used to assess the long-term stowage effects on the deployment capability of bi-stable tape springs including the friction, nonlinear-elastic and viscoelastic effects. A finite element method was used to model a meter-class fully coiled bi-stable tape spring boom and verified by analytical models.

  • 6.
    Mao, Huina
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Sinn, T.
    Vasile, M.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Simulation and control of a space web deployed by centrifugal forces in a sounding rocket experiment2016In: AIAA Modeling and Simulation Technologies Conference, 2016, American Institute of Aeronautics and Astronautics Inc, AIAA , 2016Conference paper (Refereed)
    Abstract [en]

    A deployable space web is a flexible structure that can act as a lightweight platform for construction of large structures in space. In order to save space and energy for small deployable structures, a one-step deployment method was a possible choice for future web deployment without complicated extending mechanisms. The aim of the Suaineadh experiment was to deploy and stabilize a space web by centrifugal forces and act as a test bed of the one-step deployment. Suaineadh, a 2 × 2 m2 space web, was ejected from the nose cone of REXUS-12 sounding rocket and deployed in a micro-gravity environment. A developed control law and a reaction wheel were used to control the deployment. Results from ground tests, simulations and former sounding rocket experiments were used to design the structure, folding pattern, control parameters and the deployment. During the experiment, the web was deployed but entanglements occurred since the web did not start to deploy at the specified proper initial angular velocity. It might be due to the broken inertial measurement unit which failed to detect the required spin rate of the hub or other unknown problems. The deployment dynamics was reconstructed from the information recorded by inertial measurement units and cameras. Simulations show that if the Suaineadh space web started to deploy at the specified proper angular velocity, the web would most likely have been deployed and stabilized in space by the motor, reaction wheel and controller used in the experiment. In actual flight, out-of-plane motions were observed both in deployment and stabilization phases. In order to stabilize the out-of-plane motions and reduce the risk of entanglement observed from experiment, simulation results show that small reaction wheels could be used before or during web deployment. Tape springs could also be used as web arms to avoid entanglement.

  • 7.
    Mao, Huina
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Experiments and analytical modeling for designing tape spring composites2017In: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2017Conference paper (Refereed)
    Abstract [en]

    Lightweight fiber reinforced tape spring composites are proposed for deployable space structures for nanosatellites. Neutral stable carbon fiber tape springs and bi-stable glass fiber tape springs were manufactured and their self-deployabilities after stowage were experimentally tested. The viscoelastic effects of the composites used were experimentally investigated. An analysis methodology that predicts neutral stability or bi-stability in appropriately arranging fiber directions, layups and fabric properties is presented. A design method flowchart is presented to give a reference for designing neutral or bi-stable tape springs based on the experiments and the analytical model, e.g., material type, layup, fibers direction and stability parameters. The tape spring properties before and after stowage can be predicted. The analytical model shows that fabrics of high strength fibers and low shear modulus resin with layer angle ±45° are good choices for neutrally tape springs and adding inner 0°/90° layers can increase the deployment force for bi-stable tape springs. The bi-stable glass fiber tape springs that can self-deploy after more than 6 months of stowage and high strength carbon fiber neutrally tape springs were fabricated. 

  • 8. Palma, Giorgio
    et al.
    Mao, Huina
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Burghignoli, Lorenzo
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Iemma, Umberto
    Acoustic Metamaterials in Aeronautics2018In: Applied Sciences, E-ISSN 2076-3417, Vol. 8, no 6, article id 971Article in journal (Refereed)
    Abstract [en]

    Metamaterials, man-made composites that are scaled smaller than the wavelength, have demonstrated a huge potential for application in acoustics, allowing the production of sub-wavelength acoustic absorbers, acoustic invisibility, perfect acoustic mirrors and acoustic lenses for hyper focusing, and acoustic illusions and enabling new degrees of freedom in the control of the acoustic field. The zero, or even negative, refractive sound index of metamaterials offers possibilities for the control of acoustic patterns and sound at sub-wavelength scales. Despite the tremendous growth in research on acoustic metamaterials during the last decade, the potential of metamaterial-based technologies in aeronautics has still not been fully explored, and its utilization is still in its infancy. Thus, the principal concepts mentioned above could very well provide a means to develop devices that allow the mitigation of the impact of civil aviation noise on the community. This paper gives a review of the most relevant works on acoustic metamaterials, analyzing them for their potential applicability in aeronautics, and, in this process, identifying possible implementation areas and interesting metabehaviors. It also identifies some technical challenges and possible future directions for research with the goal of unveiling the potential of metamaterials technology in aeronautics.

1 - 8 of 8
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