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  • 1.
    Cuenca, Jacques
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Inverse estimation of the elastic and anelastic properties of the porous frame of anisotropic open-cell foams2011Conference paper (Other academic)
  • 2.
    Cuenca, Jacques
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Inverse estimation of the elastic and anelastic properties of the porous frame of anisotropic open-cell foams2012In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 132, no 2, p. 621-629Article in journal (Refereed)
    Abstract [en]

    This paper presents a method for simultaneously identifying both the elastic and anelastic properties of the porous frame of anisotropic open-cell foams. The approach is based on an inverse estimation procedure of the complex stiffness matrix of the frame by performing a model fit of a set of transfer functions of a sample of material subjected to compression excitation in vacuo. The material elastic properties are assumed to have orthotropic symmetry and the anelastic properties are described using a fractional-derivative model within the framework of an augmented Hooke's law. The inverse estimation problem is formulated as a numerical optimization procedure and solved using the globally convergent method of moving asymptotes. To show the feasibility of the approach a numerically generated target material is used here as a benchmark. It is shown that the method provides the full frequency-dependent orthotropic complex stiffness matrix within a reasonable degree of accuracy.

  • 3.
    Cuenca, Jacques
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. Siemens Industry Software, Interleuvenlaan 68, Leuven, B-3001, Belgium.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    De Ryck, L.
    Lähivaara, T.
    Inverse parameter estimation in resonant, coupled fluid-structure interaction problems2018In: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics, KU Leuven - Departement Werktuigkunde , 2018, p. 2155-2169Conference paper (Refereed)
    Abstract [en]

    This work discusses the estimation of model parameters in resonant coupled systems over a wide frequency range. Such problems are known to be subjected to local minima, which represent a major obstacle in the field of parameter identification. This work evaluates various approaches to finding the global minimum, i.e. the true model parameters. The L2 norm between a target and a model frequency response function is used as the objective function. The estimation is performed through deterministic and statistical inversion frameworks, using both full-spectrum and step-wise approaches. The occurrence and the background of local minima are discussed and the performance of the different solution methods is evaluated. In particular, the correlation between different model parameters is analysed and observed to control the path towards the solution. Two illustrative examples are proposed, including the estimation of geometrical and material properties of an expansion chamber coupled to a limp porous material.

  • 4.
    Cuenca, Jacques
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. Siemens Industry Software, Leuven Belgium.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. Centre for ECO2 Vehicle Design.
    de Ryck, Laurent
    Siemens Industry Software, Leuven Belgium.
    Lähivaara, Timo
    University of Eastern Finland.
    Inverse parameter estimation in resonant, coupled fluidstructure interaction problems2018Conference paper (Refereed)
  • 5.
    Cuenca, Jacques
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Van der Kelen, Christophe
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Structural and vibroacoustics. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    A general methodology for inverse estimation of the elastic and anelastic properties of anisotropic open-cell porous materials-with application to a melamine foam2014In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 115, no 8, p. 084904-Article in journal (Refereed)
    Abstract [en]

    This paper proposes an inverse estimation method for the characterisation of the elastic and anelastic properties of the frame of anisotropic open-cell foams used for sound absorption. A model of viscoelasticity based on a fractional differential constitutive equation is used, leading to an augmented Hooke's law in the frequency domain, where the elastic and anelastic phenomena appear as distinctive terms in the stiffness matrix. The parameters of the model are nine orthotropic elastic moduli, three angles of orientation of the material principal directions and three parameters governing the anelastic frequency dependence. The inverse estimation consists in numerically fitting the model on a set of transfer functions extracted from a sample of material. The setup uses a seismic-mass measurement repeated in the three directions of space and is placed in a vacuum chamber in order to remove the air from the pores of the sample. The method allows to reconstruct the full frequency-dependent complex stiffness matrix of the frame of an anisotropic open-cell foam and in particular it provides the frequency of maximum energy dissipation by viscoelastic effects. The characterisation of a melamine foam sample is performed and the relation between the fractional-derivative model and other types of parameterisations of the augmented Hooke's law is discussed.

  • 6.
    Cuenca, Jacques
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. Siemens Industrial Software, Leuven Belgium.
    Van der Kelen, Christophe
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. Centre for ECO2 Vehicle Design.
    Inverse estimation of the elastic and anelastic properties of anisotropic foams: study of the static/dynamic separation.2015In: EURONOISE 2015, 2015Conference paper (Refereed)
    Abstract [en]

    This paper investigates the modelling and characterisation of the porous frame of anisotropic open-cell foams. The main objective is to nd a suitable model for describing the elastic and anelasticproperties of the material by making as few assumptions as possible. The proposed model is basedon a fractional di erential equation, taking into account the deformation memory of the materialin a versatile and compact manner. In the frequency domain, this results in an augmented Hooke'slaw, where the sti ness matrix of the porous frame consists of a superposition of a fully-relaxed,frequency-independent elastic part, and a dynamic, frequency-dependent anelastic part. In order toestimate the properties of the material and to determine if the elastic and anelastic parts sharethe same material symmetry, two separate experiments are performed. A static photometry setup isdesigned, where a cubic sample of material is compressed along each of the three directions of spacewhile the deformation is recorded on the four exposed faces. Furthermore, a dynamic measurementof a set of transfer functions between each pair of opposed faces of the sample is performed. Thecharacterisation methodology consists of an inverse estimation of the parameters of the model. Thisis acheved by replicating each experiment as a nite element simulation and tting the model byusing an optimisation algorithm. The static and dynamic observations serve as a basis for discussingthe independence of the elastic and anelastic properties of the material.

  • 7.
    Cuenca, Jacques
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. Siemens Industrial Software Leuven Belgium.
    Van der Kelen, Christophe
    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, MWL Numerical acoustics.
    Inverse estimation of the elastic and anelastic properties of anisotropic open-cell foams2014Conference paper (Other academic)
  • 8.
    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)
  • 9.
    Göransson, Peter
    et al.
    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.
    Lähivaara, Timo
    University of Eastern Finland.
    Parameter estimation in modelling frequency response of coupled systems using a stepwise approach2019In: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 126, p. 161-175Article in journal (Refereed)
    Abstract [en]

    This paper studies the problem of parameter estimation in resonant, acoustic fluid-structure interaction problems over a wide frequency range. Problems with multiple resonances are known to be subjected to local minima, which represents a major challenge in the field of parameter identification. We propose a stepwise approach consisting in subdividing the frequency spectrum such that the solution to a low-frequency subproblem serves as the starting point for the immediately higher frequency range. In the current work, two different inversion frameworks are used. The first approach is a gradient-based deterministic procedure that seeks the model parameters by minimising a cost function in the least squares sense and the second approach is a Bayesian inversion framework. The latter provides a potential way to assess the validity of the least squares estimate. In addition, it presents several advantages by providing invaluable information on the uncertainty and correlation between the estimated parameters. The methodology is illustrated on synthetic measurements with known design variables and controlled noise levels. The model problem is deliberately kept simple to allow for extensive numerical experiments to be conducted in order to investigate the nature of the local minima in full spectrum analyses and to assess the potential of the proposed method to overcome these. Numerical experiments suggest that the proposed methods may present an efficient approach to find material parameters and their uncertainty estimates with acceptable accuracy.

  • 10.
    Göransson, Peter
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. Centre for ECO2 Vehicle Design.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. Siemens Industry Software, Leuven Belgium.
    Lähivaara, Timo
    University of Eastern Finland.
    Some Observations on Parameter Estimation in Strongly Coupled Fluid-Structure Interaction Problems2018Conference paper (Other academic)
  • 11.
    Göransson, Peter
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. Siemens Industry Software Leuven Belgium.
    Van der Kelen, Christophe
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    EXPERIMENTAL-NUMERICAL METHODS FOR INVERSE CHARACTERISATION OF SOME MATERIAL PROPERTIES OF ANISTROPIC-ANELASTIC POROUS MATERIALS2015Conference paper (Refereed)
  • 12.
    Manzari, Luca
    et al.
    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.
    Lopez Arteaga, Ines
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    A fully automated high-speed optical rig for in vacuo, full field, non-contact vibration measurements for viscoelastic, anisotropic materials2018Conference paper (Refereed)
    Abstract [en]

    In this paper, a setup for measuring the three-dimensional displacement field of a test object un-dergoing controlled dynamic excitation in a vacuum chamber is presented. The setup has beendesigned with porous materials in mind, yet is suitable for the measurement of anisotropic vis-coelastic solids in general. To achieve non-contact data acquisition, a stereo high-speed camerasystem measures the displacement of the foundation and of the test object. A laser Doppler vi-brometer is used before the actual measurement to choose an excitation level that maximizes thesignal-to-noise ratio while allowing to ensure that the test object is fully relaxed and stable at thebeginning of every measurement. The setup, comprising both commercial and in-house hardwareand software solutions, addresses the challenges of measuring in vacuum with non-contact tech-niques. All these aspects are discussed in the current paper, and preliminary results are presented.The ultimate objective is to estimate the dynamic properties of a material using inverse methodsand the data obtained.

  • 13.
    Manzari, Luca
    et al.
    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.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Lopez Arteaga, Ines
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Toward fully anisotropic viscoelastic material models using an automated high-speed optical rig2018In: 13TH INTERNATIONAL CONFERENCE ON VIBRATION MEASUREMENTS BY LASER AND NONCONTACT TECHNIQUES, 2018 / [ed] Tomasini, E P, IOP PUBLISHING LTD , 2018, article id 012003Conference paper (Refereed)
    Abstract [en]

    This paper describes some of the algorithms that are employed in the post-processing of the data obtained from an automated high-speed optical rig. The setup, entirely designed by some of the authors, is used for measuring the full field displacement in time of anisotropic viscoelastic solids undergoing controlled dynamic excitation. The setup main goal is to provide complex transfer functions relating the three-dimensional sinusoidal displacement on the surface of the sample to the sinusoidal motion of the foundation, suitable for the inverse estimation of the dynamic properties of the material under analysis. The complete automation of the measurement process aims at maximizing repeatability and signal-to-noise ratio. In particular, a stereo high-speed camera system is responsible for the actual measurement, while a laser Doppler vibrometer is used for a preliminary autoranging procedure and for data validation. The camera system does not directly output the high-quality data that is needed for a successful, physically meaningful inverse estimation. Hence, here the algorithms described in this paper come into play. Since digital image correlation (DIC) may fail in some frames or in some regions of the pictures, a mask is applied and calculated for every measurement run to preserve information only where the success rate of the DIC algorithm is higher than a specified threshold. The sample is mounted on a foundation whose sides are flat: random sample consensus (RANSAC) and principal component analysis (PCA) are used to respectively eliminate outliers and find the best fitting plane to the foundation side - the measured displacement field can then be expressed in a local coordinate system, truly relative to the foundation. The transfer functions are now obtained in two steps: first an optimizer is used to fit a cosine to all the measured displacement time-series, then the complex amplitudes representing the motion of the sample faces are divided by the average of the complex amplitudes representing the motion of the foundation.

  • 14.
    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

  • 15.
    Parra Martinez, Juan Pablo
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. Siemens Industry Software.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Dazel, Olivier
    LAUM UMR CNRS 6613.
    Optimal alignment of anisotropic poroelastic cores in multilayered systems for acoustic performance2016In: Article in journal (Other academic)
  • 16.
    Parra Martinez, Juan Pablo
    et al.
    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. LAUM, UMR CNRS, France.
    Dazel, Oliver
    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.
    Acoustic behaviour and internal energies of multilayer systems including anisotropic poroelastic materialsManuscript (preprint) (Other academic)
  • 17.
    Parra Martinez, Juan Pablo
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Dazel, Olivier
    LAUM UMR CNRS 6613.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. Siemens Industry Software.
    Acoustic analysis of anisotropic poroelastic multilayered systems2016In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, ISSN 1089-7550, Vol. 119, no 8, p. 084907-Article in journal (Refereed)
    Abstract [en]

    The proposed method allows for an extended analysis of the wave analysis, internal powers, and acoustic performance of anisotropic poroelastic media within semi-infinite multilayered systems under arbitrary excitation. Based on a plane wave expansion, the solution is derived from a first order partial derivative as proposed by Stroh. This allows for an in-depth analysis of the mechanisms controlling the acoustic behaviour in terms of internal powers and wave properties in the media. In particular, the proposed approach is used to highlight the influence of the phenomena intrinsic to anisotropic poroelastic media, such as compression-shear coupling related to the material alignment, the frequency shift of the fundamental resonance, or the appearance of particular geometrical coincidences in multilayered systems with such materials.

  • 18.
    Parra Martinez, Juan Pablo
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Dazel, Olivier
    LAUM UMR CNRS 6613.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. Siemens Industry Software.
    Derivation of the state matrix for dynamic analysis of linear homogeneous media2016In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 140, no 2, p. EL218-EL220Article in journal (Refereed)
    Abstract [en]

    A method to obtain the state matrix of an arbitrary linear homogeneous medium excited by a plane wave is proposed. The approach is based on projections on the eigenspace of the governing equations matrix. It is an alternative to manually obtaining a linearly independent set of equations by combining the governing equations. The resulting matrix has been validated against previously published derivations for an anisotropic poroelastic medium.

  • 19.
    Parra Martinez, Juan Pablo
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. LAUM - UMR CNRS.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Dazel, Olivier
    LAUM - UMR CNRS.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Analysis of the frequency response behaviour of anisotropic multilayered structures and potential acoustic performance optimizations2014In: Proceedings of ISMA 2014 - International Conference on Noise and Vibration Engineering and USD 2014 - International Conference on Uncertainty in Structural Dynamics, Leuven, Belgium: KU Leuven , 2014, p. 4279-4290Conference paper (Refereed)
    Abstract [en]

    Anisotropy of elastic and acoustic properties increases the potential for performance tailoring of multilayered structures including poroelastic materials. An intrinsic part of such a design optimization is to understand the frequency response behaviour of such configurations in general and those including anisotropic porous layers in particular. In this work a plane wave method for anisotropic multilayered structures has been used to study the response sensitivity for anisotropic porous materials as a function of their material coordinate orientation. It is shown that, depending on the frequency range of interest, the sensitivity to the orientation of the anisotropic porous material varies. 

  • 20.
    Parra Martinez, Juan Pablo
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. LAUM UMR CNRS 6613.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Dazel, Olivier
    LAUM UMR CNRS 6613.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. Siemens Industry Software.
    Calculation of internal powers for anisotropic porous materials within multilayered structures based on plane wave approximation2015Conference paper (Other academic)
    Abstract [en]

    This paper presents a method for calculating internal powers of multilayered configurations with anisotropic porous materials. The methodology takes a plane wave solution for anisotropic multilayered structures as a mathematical base for the derivation of the corresponding integral expressions. Different physical phenomena within the assessed structure can be then studied in detail as a whole or in terms of partial contributions to the total power balance. In the paper, an analysis of the dissipation in an anisotropic porous material as a function of its material coordinate orientation is performed.

  • 21.
    Parra Martinez, Juan Pablo
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Dazel, Olivier
    LAUM UMR CNRS 6613.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. Siemens Industry Software.
    Jaouen, Luc
    Matelys-Research Lab.
    Wave analysis of intrinsic phenomena related to anisotropic poroelastic materials in multilayered systems2016Conference paper (Refereed)
    Abstract [en]

    An analysis of intrinsic dynamic phenomena in anisotropic poroelastic media is presented, based on a plane wave formulation. The latter is derived from the Stroh formalism on the state variables governing the beha- viour of such media. A particular interest is given to the compression-shear coupling related to the material alignment of the anisotropic poroelastic core. This coupling motion can be directly correlated to the ma- terial mechanical parameters and affects the response of the overall structure in specific frequency ranges. Furthermore, the effect of the anisotropic poroelastic material coordinate orientation on the the acoustic and elastical response of multilayered systems with such material cores is investigated under diffuse field excita- tion conditions (i.e. only a part the mechanics which doesnt include maximum stress at rupture). An insight into other effects of anisotropy is provided, such as the frequency shift of the fundamental resonance related to the core material alignment and the appearance of particular geometrical coincidences in the acoustic behaviour of the system.

  • 22.
    Van der Kelen, Christophe
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Structural and vibroacoustics. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    A method for characterisation of the static elastic properties of the porous frame of orthotropic open-cell foams2015In: International Journal of Engineering Science, ISSN 0020-7225, E-ISSN 1879-2197, Vol. 86, p. 44-59Article in journal (Refereed)
    Abstract [en]

    This paper proposes a method to identify the static, fully relaxed elastic Hooke's matrix of a porous open-cell material. The moduli are estimated through an inverse estimation method, by performing a fit of a numerical model on the measured displacements on the faces of the porous material. These displacements are obtained from a static compression along each of the three coordinate axes. The material is modelled as an orthotropic equivalent solid, of which the principal directions are not necessarily aligned with the orthonormal coordinate system in which the experiments are conducted. The angles of relative orientation accounting for the misalignment are among the properties to be estimated. The focus in this paper is on the methodology itself, and its validity is verified by applying the method to four artificial materials with different levels of anisotropy. In addition, the robustness of the method to perturbations on the input data is investigated.

  • 23.
    Van der Kelen, Christophe
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Structural and vibroacoustics. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    A method for inverse estimation of the static elastic properties of anisotropic poroelastic foams - with application to a melamine foam2013Report (Refereed)
    Abstract [en]

    The paper presents a method for the characterisation of the static, fully relaxed elastic properties of poroelastic materials. The approach is based on full field measurements of the 3D displacements in a number of points on the faces of the compressed material sample. These are used as targets in an inverse estimation to fit a model of the material to experimental data. In the current work, the material is modelled as an orthotropic equivalent solid, of which the principal directions are not necessarily aligned with the orthonormal coordinate system in which the experiments are conducted. The angles of relative orientation accounting for the misalignment are among the properties to be estimated. In addition, the proposed model considers the region of reduced stiffness close to material discontinuities, which has been identified in previous investigations. The method presented is verified for an artificial material, and its robustness is studied. A characterised melamine foam is found to have an orthotropic symmetry, and its lowest stiffness in the direction parallel to the rise direction of the material.

  • 24.
    Van Der Kelen, Christophe
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Ultrasound.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Ultrasound.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Ultrasound.
    A method for the inverse estimation of the static elastic compressional moduli of anisotropic poroelastic foams-With application to a melamine foam2015In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 43, p. 123-130Article in journal (Refereed)
    Abstract [en]

    This paper presents the application of a method for the characterisation of the static, fully relaxed elastic properties of poroelastic materials. The approach is based on full field measurements of the 3D displacements in a number of points on the faces of the compressed material sample. These are used as targets in an inverse estimation to fit a model of the material to the experimental data. The material is modelled as an orthotropic equivalent solid, whose principal directions are not necessarily aligned with the coordinate system in which the experiments are conducted. The angles of relative orientation accounting for the potential misalignment are estimated, together with the elastic moduli of the material. In addition, the proposed model considers the region of reduced stiffness close to material discontinuities, which has been identified in previous investigations. The method is applied to a melamine foam, which is found to have its lowest stiffness in the direction parallel to the rise direction of the material. © 2015 Elsevier Ltd All rights reserved.

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