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  • 1.
    Cameron, Christopher John
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lind, Eleonora
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Material Property Steered Optimization of a Multifunctional Body Panel to Structural and Acoustic Constraints2009In: Proceedings of the 17th International Conference on Composite Materials, 2009Conference paper (Other academic)
    Abstract [en]

    A conventional automobile roof, including structural and interior trim components, is replaced with a multi-layer, multi-functional sandwich construction. A weight optimizationis performed to tailor the material properties of the composite face sheets and multiple foam layers to meet structural constraints and acoustic requirements.

  • 2.
    Cameron, Christopher John
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Lind, Eleonora
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Proposal of a Methodology for Multidisciplinary Design of Multifunctional Vehicle Structures including an Acoustic Sensitivity Study2009In: International Journal of Vehicle Structures & Systems, ISSN 0975-3060, Vol. 1, no 1-3, 3-15 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, a design methodology is proposed, wherein tools and knowledge from the areas of structural design, numerical optimization, and noise, vibration and harshness (NVH) engineering are combined into a single toolbox for vehicle design. The methodology attempts to address the topic of sustainable development from both economic and environmental perspectives within the vehicle industry. A brief review of the topics of NVH and numerical optimization is given for the purposes of disseminating knowledge. Finite element codes for predicting structural and acoustic response are implemented within the iterative design methodology, which is explained for generic problems. Specific focus is placed on the need for understanding functional requirements of the entire system rather than its components. The methodology is implemented in an automotive case study. The results in terms of design solution and development framework are evaluated and discussed. As part of this evaluation, and integral to the design process, an acoustic sensitivity analysis of the final solution is performed and the results are presented.

     

     

  • 3.
    Cameron, Christopher John
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Lind Nordgren, Eleonora
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Material Property Steered Structural and Acoustic Optimization of a Multifunctional Vehcile Body PanelManuscript (preprint) (Other academic)
    Abstract [en]

    Conventional vehicle passenger compartments often achieve functional requirements using a complex assembly of components. As each component is optimized for a single task, the assembly as a whole is often suboptimal in achieving the system performance requirements. In this paper, a novel iterative design approach based on using a multi-layered load bearing sandwich panel with integrated acoustic capabilitiesis developed focusing on material properties and their effecton the systems behavior. The proposed panel is meant to fulfilmultiple system functionalities simultaneously, thus simplifying the assembly and reducing mass. Open cell acoustic foams are used to achieve acoustic performance, and the effect of altering the stacking sequence as well as introducing an air gap within the acoustic treatment is studied in detail to determine effects on the acoustic and structural performance of the panel as a whole.

  • 4.
    Cameron, Christopher John
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Rahmqvist, Sven
    Saab Automobile AB.
    Structural: acoustic Design of a Multi-functional Sandwich Body Panel for Automotive Applications2008In: Proceedingsof the 8th International Conference on Sandwich Structures / [ed] A. J. M. Ferreira, 2008, 896-907 p.Conference paper (Other academic)
  • 5.
    Cameron, Christopher
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Lind, Eleonora
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Balancing structural and acoustic performance of sandwich panels for vehicle applications with topology, property, and size optimization2010In: 7th Asian-Australasian Conference on Composite Materials 2010, ACCM 2010, ACCM-7 Organizing Committee , 2010, Vol. 2, 835-838 p.Conference paper (Refereed)
    Abstract [en]

    Within this paper, a process for the design of a multifunctional sandwich body panel for vehicle applications is proposed. The method, presented with a case study, attempts to achieve a balance between structural and acoustic performance using numerical tools for topology optimization and combined size and property optimization. The goal of the work is to achieve an optimal distribution of traditional sandwich foam material and light weight acoustic foam within the core of the panel. The significance of the coupling between the panels inner face sheet and the acoustic foam is examined and proves to be a critical parameter in the design. An adaptation to existing topology optimization schemes is proposed to deal with the presence or absence of such a coupling. The results show promise in simplifying construction, reducing weight, and streamlining the assembly process.

  • 6.
    Cameron, Christopher
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Multi-Scale Structural-Acoustic Optimization of a Multi-Functional Vehicle Body Panel2009Conference paper (Other academic)
  • 7.
    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)
  • 8.
    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, 084904- p.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.

  • 9.
    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.

  • 10.
    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)
  • 11.
    Dazel, Olivier
    et al.
    U de Maine.
    Brouard, Bruno
    U de Maine.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    An efficient solver for finite-element poroelastic problems2011Conference paper (Other academic)
  • 12. Deckers, Elke
    et al.
    Hörlin, Nils-Erik
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Vandepitte, Dirk
    Desmet, Wim
    A Wave Based Method for the efficient solution of the 2D poroelastic Biot equations2012In: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, E-ISSN 1879-2138, Vol. 201, 245-262 p.Article in journal (Refereed)
    Abstract [en]

    The vibro-acoustic behaviour of poroelastic materials is often formulated as boundary value problems based on the continuum mechanics Blot's theory expressed as two coupled partial differential equations. This paper presents an extension of the Wave Based Method (WBM), a numerical technique to solve these vibro-acoustic boundary value problems in a computationally efficient manner. At present, the Finite Element Method (FEM) is the most commonly used prediction technique to deal with these Biot equations, but suffers from the disadvantage that the system matrices have to be recalculated for each frequency of interest due to the frequency-dependent equation parameters. This harms the inherent effectiveness of the FEM. Additionally, due to the discretisation into a large number of small finite elements and the high number of unknowns per node, the computational efforts involved practically restrict the use of FEM to low-frequency applications. The method discussed in this paper is based on an indirect Trefftz approach. Exact solutions of the three coupled waves, supported by Biot's equations, are used as basis functions in a solution expansion to approximate the field variables in a poroelastic boundary value problem. This approach leads to smaller systems of equations, enabling an efficient solution at higher frequencies.

  • 13.
    Dovstam, Krister
    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.
    Generic FE modelling of linear interface damping in vibrating structures2008In: PROCEEDINGS OF ISMA 2008: INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING, VOLS. 1-8, 2008, 843- p.Conference paper (Refereed)
  • 14.
    Dovstam, Krister
    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.
    Is damping additive?: On the accumulated effect of interface damping and material damping2010Conference paper (Other academic)
    Abstract [en]

    Traditionally the structural loss factor of a vibrating structure at resonance is defined by the half power bandwidth which then incorporates all mechanisms, e. g. material damping, interface damping, added viscoelastic damping, acoustic damping and damping in joints, contributing to the total damping. Damping measures based on vibration response data and vibration energy dissipated locally at interfaces and in material volumes may be computed in post processing finite element computations. Appropriately defined measures may then localize the damping to interfaces and material volumes where the dissipation actually occurs. It is also possible to separate and quantify the damping contributions from different damping sources. The interaction and combined effect of mixed material and interface damping is studied for a simple, three dimensional, build-up structure containing overlapping contact interfaces and internal regions with material damping. Results are presented based on damping measures which separate damping contributions from different contact interfaces and internal material volumes. By comparison of the total structural damping with partial contributions, from the specific damping sources occurring in each case, the combined, accumulated, effect of the different sources is investigated. The question whether different kinds of damping is additive or not is finally addressed.

  • 15.
    Dovstam, Krister
    et al.
    Dovstam Innovat.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Mode based prediction of vibrations in highly damped structures2006In: Proceedings of ISMA2006: International Conference on Noise and Vibration Engineering, 2006, 1029-1038 p.Conference paper (Refereed)
    Abstract [en]

    Traditionally, mode based techniques are used for prediction of sound and vibrations. This is motivated by the possibility of using reduced modal models instead of very detailed FE models. For highly damped, composite structures the effect of reduced model size on the accuracy of predicted sound and vibration levels is often not known. Problems connected with application of modal methods towards highly damped materials, systems and multilayer treatments using conventional modal vibration theory have recently been highlighted by the authors. In the present paper a simple, damped Oberst beam example is presented, not hitherto satisfactorily treated by modal techniques. It is pointed out that the contact forces at internal interfaces between different materials have to be treated in order for a modal solution to be found. It is also shown that non-physical tractions at free unloaded boundary surfaces have to be eliminated.

  • 16.
    Dovstam, Krister
    et al.
    Dovstam Innovations.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Semeniuk, Bradley
    Rieter Automotive Managment AG, Switzerland.
    Mode based prediction of vibrations in complex automotive structures, a review of shortcomings2005Conference paper (Refereed)
  • 17.
    Färm, Anna
    et al.
    Centre for ECO Vehicle Design, Scania CV, Södertälje, Sweden.
    Boij, Susann
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Flow acoustics.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Glav, Ragnar
    Scania CV, Södertälje, Sweden.
    On internal mean flow in porous absorbers and its effect on attenuation properties2013In: Proceedings of Meetings on Acoustics: Volume 19, 2013, Acoustical Society of America (ASA), 2013, Vol. 19, 1-6 p.Conference paper (Other academic)
    Abstract [en]

    In vehicle applications, absorbing materials are often used to attenuate sound. In, for example, exhaust systems and on noise encapsulations, the absorber is exposed to flow. This creates a boundary layer above the absorber, which affects the impedance of the surface, and hence alters the absorption properties. In addition to this effect, the flow itself may enter the absorbent material due to high pressure and forced flow paths. An investigation of the effects that internal flow in the absorber imposes on the acoustic properties is presented. One way to describe the effect is by a change in flow resistivity. The effect is investigated for typical absorbers used in noise encapsulations for trucks. The Transfer Matrix Method is applied to calculate the resulting absorption coefficient for an absorber with changed flow resistivity due to internal flow. The possibility to model the changed properties of the absorber with internal mean flow by means of Biot theory is also explored, together with a discussion on suitable experimental methods to verify and further investigate the effects.

  • 18.
    Gao, Kun
    et al.
    Eindhoven University of Technology, Mechanics of Materials, Department of Mechanical Engineering, The Netherlands.
    van Dommelen, J A W
    Eindhoven University of Technology, Department of Mechanical Engineering, The Netherlands.
    Geers, M G D
    Eindhoven University of Technology, Department of Mechanical Engineering, The Netherlands.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Microstructure-based numerical modelling of foams for acoustic shielding2014In: 21st International Congress on Sound and Vibration 2014, ICSV 2014, International Institute of Acoustics and Vibrations , 2014, 881-887 p.Conference paper (Refereed)
    Abstract [en]

    In this paper, a numerical homogenization approach is proposed to obtain isotropic Biot's parameters based on the microstructure of an porous material. It is assumed that a macroscopic point can be represented by a microscopic Representative Volume Element (RVE) consisting of the solid and the fluid. The macroscopic properties are controlled by Biot's equations and the RVE is governed by linearized balance equations for momentum and linear constitutive laws. With suitable boundary conditions, the micro-macro relation is formulated based on consistency of energy. Then, Biot's parameters are calculated through the response of the RVE. By following this new homogenization approach, examples with simple microstructures are given and simulations of two sound absorption experiments are conducted by using Biot's equations. The results are compared with Direct Numerical Simulations and it shows a favourable performance of this new approach compared to the alternative Transfer Matrix Method.

  • 19.
    Gao, Kun
    et al.
    TU Eindhoven, Netherlands.
    van Dommelen, J A W
    TU Eindhoven, Netherlands.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Geers, M G D
    TU Eindhoven, Netherlands.
    Homogenization of sound propogation in a deformable porous material based on microscopic viscous-thermal effects.2014Conference paper (Refereed)
  • 20.
    Gao, Kun
    et al.
    TU Eindhoven.
    Van Dommelen, J. A. W.
    TU Eindhoven.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Geers, M. G. D.
    TU Eindhoven.
    Microstructure-based numerical modeling of the solid-fluid coupling interaction in acoustic foams2013In: Poromechanics V - Proceedings of the 5th Biot Conference on Poromechanics, 2013, 2123-2130 p.Conference paper (Refereed)
    Abstract [en]

    In this paper, based on a representative volume element (RVE) and Slattery’s averaging theorem, parameters of Biot’s poroelastic equations for homogenous isotropic porous materials are obtained. According to Slattery’s averaging theorem, the coupling terms, which describe the inertial effects and the viscous effects, are represented by an integral of the solid-fluid interaction force. This relation provides a new approach to obtain the parameters required in Biot’s equations through a direct numerical simulation of the RVE. An example of a 2D RVE is given and simulations of sound propagation in an impedance tube with a foam are conducted using Biot’s equations. It is shown that the numerical coupling mass obtained from this new approach behaves qualitatively the same as an associated phenomenological model.

  • 21.
    Guastavino, Remi
    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.
    Vibration Dynamics Modeling of Anisotropic Porous Foam Materials2005Conference paper (Refereed)
    Abstract [en]

    For an accurate prediction of the low to medium frequency surface vibration and sound radiation behavior of multilayer trim components with polyurethane foam core materials, improved means of estimating the dynamic elastic and damping properties of the foam are necessary. This is due to the fact that in the manufactured porous polyurethane foam materials typically used in acoustic trim components, there is a geometric anisotropy in the foam cell microstructure. The foam cells and struts are elongated in the rise and injection flow directions of the manufacturing process. The density, elastic and damping properties of the foam can then be considered to be highly dependent upon manufacturing process techniques, along with the polyurethane chemical formulations. For a balanced cost and acoustic performance optimization of these materials in the product development cycle, it is important that this inherent anisotropy is correctly represented in the acoustical numerical simulation methodology. Through a hybrid combination of experimental deformation and strain field mapping, and physically based porous material acoustic Finite Element (FE) simulation modeling, the anisotropic dynamic elastic coefficients and damping properties of the foam may be correctly estimated. This new methodology of model-based porous material characterization is demonstrated here for a simplified seismic mass configuration. The improved accuracy of the subsequent low-mid frequency multilayer surface vibration numerical predictions is discussed. This leads to improved NVH analysis during the development lifecycle of the vehicle acoustic sound package, allowing a better balance between acoustic performance and a minimization of material usage to be achieved.

  • 22.
    Guastavino, Remi
    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.
    Hörlin, Nils-Erik
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Characterisation of anisotropic porous foam materials2005Conference paper (Other academic)
  • 23.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Advanced materials and structures for noise control2006In: EURONOISE 2006 - The 6th European Conference on Noise Control: Advanced Solutions for Noise Control, 2006Conference paper (Refereed)
    Abstract [en]

    Lightweight porous automotive acoustic multilayer trim components have been traditionally specified in terms of sound absorption and sound transmission loss performance targets. These targets are valid for airborne noise excitation only, in the medium to high frequency ranges. Unfortunately, this neglects the fact that in real-world applications, these components are also subjected to low-medium frequency structural vibration inputs from the mechanical components, which is typically an acoustic sound radiation problem. For a flexible, open cell porous foam, the transport of energy is carried both through the sound pressure waves propagating through the fluid in the pores, and through the elastic stress waves carried through the solid frame of the material. For a given situation, the balance between energy dissipated through vibration of the solid frame, changes in the acoustic pressure and the coupling between the waves varies with the topological arrangement, choice of material properties, interfacial conditions, etc. This opens for the possibility of tailoring the performance by tuning the different dissipation mechanisms accordingly. This paper then presents some recent developments and results, Finite Element (FE) numerical simulation and material modelling, which allow the tuning and prediction of the of porous multilayer trim components.

  • 24.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Convergence aspects in finite element solutions of multi-layered, heterogeneous porous materials2011Conference paper (Other academic)
  • 25.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Exploring multi-functionality in poro-elastic materials with consideration given to some aspects related to the influence of scale, shape and space2014Conference paper (Refereed)
  • 26.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Mid frequency NVH analysis: FE modelling of acoustic and vibrational damping in porous solids2007Conference paper (Other academic)
  • 27.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Modelling of anisotropic porous materials: sensitivity in response to & influence of non-aligned material directions2014Conference paper (Other academic)
  • 28.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Simulation of multilayered porous foam structures with integrated actuators2005Conference paper (Other academic)
  • 29.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Tailoring structural and acoustic performance of poroelastic, open cell foams2009Conference paper (Other academic)
  • 30.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    The Multifunctional and Multidisciplinary Design Paradigm: noise & vibration research within the Centre for ECO2 Vehicle Design2012Conference paper (Other academic)
  • 31.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    The Multifunctional and Multidisciplinary Design Paradigm: ongoing research within the Centre for ECO2 Vehicle Design2011Conference paper (Other academic)
  • 32.
    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)
  • 33.
    Göransson, Peter
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Deü, Jean-Francois
    LMSSC, Structural Mechanics and Coupled Systems Laboratory, France.
    Dazel, Olivier
    Université du Maine.
    Sensitivity of Vibroacoustic Response in  Multi-Layered Anisotropic Poro-Elastic Panels with Non-Aligned Properties2013Conference paper (Refereed)
  • 34.
    Göransson, Peter
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Hörlin, Nils-Erik
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Anisotropic porous materials, and then?2008Conference paper (Other academic)
  • 35.
    Göransson, Peter
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Hörlin, Nils-Erik
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Semeniuk, Bradley
    Rieter Automotive Managment AG, Switzerland].
    Influence of surface porosity on the radiated sound from multilayer automotive trim components2005In: SAE 2005 Noise and Vibration Conference and Exhibition, May 2005, 2005Conference paper (Refereed)
    Abstract [en]

    Lightweight porous automotive acoustic multilayer trim components have been traditionally specified in terms of sound absorption and sound transmission loss performance targets. These targets are valid for airborne noise excitation only, in the medium to high frequency ranges. Unfortunately, this neglects the fact that in real-world vehicle applications, these components are also subjected to low-medium frequency structural vibration inputs from the mechanical components of the vehicle, which is typically an acoustic sound radiation problem.

  • 36.
    Göransson, Peter
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Lind Nordgren, Eleonora
    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.
    Vibro-acoustic energy propagation in anisotropic, anelastic porous materials2014In: Proceedings of the 9th International Conference on Structural Dynamics, EURODYN 2014, 2014, 83-90 p.Conference paper (Refereed)
    Abstract [en]

    Historically, the modelling of the acoustics of poro-elastic materials (APEMs) has assumed the materials to be isotropic in both their elastic as well as their acoustic properties including the dissipative mechanisms related to viscous, inertialand thermal interactions. While this is a reasonable approximation when the absorption of sound is of interest, it fails to provide meaningful results for most foamed materials in general and for certain sets of boundary conditions involving elastic contact with solids or other APEMs in particular. A general modelling of fully anisotropic APEMs will be reviewed and taken as a starting point for a series of numerical experiments focussing on aspects of propagation of vibro-acoustic energy, in a homogeneous layer as well as in multiple layer arrangements. From previous works it is known that the influence of anisotropy may be quite significant, in particular for structure-borne vibro-acoustic energy. In addition, it is known that the alignment of principal directions may have substantial influence on the transmission of vibro-acoustic energy. These findings will be recalled in order to prepare for a discussion on the aspects of the directional dependence of the anelastic moduli which will be the core of the presentation at the conference. Real material tensors may be constructed from a superposition of these anisotropic contributions, in the most general case, not necessarily sharing the same principal directions. Starting from these fully anisotropic constitutive tensors with general symmetry properties, studies of optimal alignment between conservative and dissipative tensors, as well as between different materials in various configurations of interest, will be illustrated in the lecture.

  • 37.
    Hörlin, Nils-Erik
    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.
    Weak, anisotropic symmetric formulations of Biot's equations for vibro-acoustic modelling of porous elastic materials2010In: International Journal for Numerical Methods in Engineering, ISSN 0029-5981, E-ISSN 1097-0207, Vol. 84, no 12, 1519-1540 p.Article in journal (Refereed)
    Abstract [en]

    In this paper a fully anisotropic symmetric weak formulation of Biot's equations for vibro-acoustic modelling of porous elastic materials in the frequency domain is proposed. Starting from Biot's equations in their anisotropic form, a mixed displacement-pressure formulation is discussed in terms of Cartesian tensors. The anisotropic equation parameters appearing in the differential equations are derived from material parameters which are possible to determine through experimental testing or micro-structural simulations of the fluid and the porous skeleton. Solutions are obtained by applying the finite element method to the proposed weak form and the results are verified against a weak displacement-based formulation for a foam and plate combination.

  • 38.
    Hörlin, Nils-Erik
    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.
    Guastavino, Remi
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Finite element modelling of multi-layered trim components: possibilities and difficulties2005Conference paper (Other academic)
  • 39.
    Ihle, Alexander
    et al.
    HPS GmbH.
    Ernst, Thomas
    HPS GmbH.
    Datashvili, Leri
    TU Munich.
    Hoffmann, Jürgen
    TU Munich.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Large porous antenna and spacecraft structures: Thermo-elastic and vibroacoustic modelling and effects and its verification via test.2009Conference paper (Other academic)
  • 40.
    Krank, Benjamin
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Structural and vibroacoustics.
    Ohlsson, Ulrika
    Volvo Group Trucks Technology.
    Hedlund, Anders
    Volvo Group Trucks Technology.
    Nordström, Lars
    Volvo Group Trucks Technology.
    Englund, Thomas
    Volvo Group Trucks Technology.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Tuning spot weld models for vehicle body structural dynamics2012In: Proceedings Of International Conference On Noise And Vibration Engineering (ISMA2012) / International Conference On Uncertainty In Structural Dynamics (USD2012), Katholieke Universiteit Leuven , 2012, 3915-3926 p.Conference paper (Refereed)
    Abstract [en]

    Efforts focussing on modelling of spot welds in typical automotive structures have been spent during the last decades resulting in a number of different modelling techniques. One of the crucial aspects common to all these approaches is the difficulties related to the local complexity of the modelling of the actual connections. In order to handle this complexity, spot weld models are often dependent on parameters tuning their characteristics. This paper discusses the tuning of two different spot weld models with respect to certain parameters; the RBE3-Hexa-RBE3 model (also known as the ACM 2) and the Spider2 model available in the pre-processor Ansa. With the current trend towards increasingly refined finite element model meshes, current guide lines need to be updated and elaborated further in order to identify the best performing models. In this paper, model studies are discussed targeting tuning of spot weld parameters together with a new proposal for an exact method for updating the Young's modulus and density of isotropic shell structures analytically using an initial FE calculation.

  • 41.
    Lind, Eleonora
    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.
    Optimising Open Porous Foam for Acoustical and Vibrational Performance2008Conference paper (Other academic)
  • 42.
    Lind Nordgren, Eleonora
    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.
    Parametric relations for porous foams and their use in optimization of structural acoustic performance of multilayer trim components2006Conference paper (Other academic)
  • 43.
    Lundberg, Eva
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. Centre for ECO2 Vehicle Design.
    Orrenius, Ulf
    Bombardier Transportation.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Comparison of two different simplified micro structures for calculating flow resistivity of anisotropic open cell porous foams.2016Conference paper (Refereed)
  • 44.
    Nadampalli, Ravi Varma
    et al.
    Daimler AG.
    Dovstam, Krister
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Structural and vibroacoustics.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Glandier, Christian
    Daimler AG.
    On linear modelling of interface damping in a complex vibrating structure2012Conference paper (Refereed)
  • 45.
    Nadampalli, Ravi Varma
    et al.
    Daimler AG.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Glandier, Christian
    Daimler AG.
    Finite element formulation and implementation of poroelastic materials in an unbonded case2012In: International Conference on Noise and Vibration Engineering 2012, ISMA 2012, including USD 2012: International Conference on Uncertainty in Structure Dynamics, Katholieke Universiteit Leuven , 2012, Vol. 3, 1815-1825 p.Conference paper (Refereed)
    Abstract [en]

    Porous material modelling in the automotive industry is gaining more importance due to the ever increasing need for reducing the weight of the car body. This trend towards weight reduction makes it all the more important to optimize acoustic treatments. Extensive research has been done on understanding the physical behaviour of porous materials and their applications. However, when it comes to design, efficient predictive tools are needed in order to allow industrial applications to be performed at a reasonable costs, i.e. time and computation resources. During the product development cycle for the computations with trim body, a good correlation can be found between the measurements and the simulations in the low frequency region. But there is more effort needed in understanding the physical behaviour of trim components when coupled with structural parts, to improve prediction accuracy in the mid frequency region. Finite element techniques are widely used in computing trimmed vehicle bodies but modelling of poroelastic materials frequently requires refined meshes. This implies an increased amount of resources needed to solve the problem, both in terms of computational time and memory allocation. As a consequence, the computational costs increase substantially when a fully trimmed car body is analysed and compared to a body-in-white structure. This paper discusses one particular aspect in the modelling of trimmed vehicle bodies, namely the coupling conditions along the surfaces where the trim and the sheet metal are interfacing. These conditions are known to vary for a number of reasons, mostly production related, and bring in sources of variation among similar car bodies leading to a higher degree of uncertainty in the NVH behaviour, potentially affecting the possibilities of optimizing the overall system performance. In this paper, an investigation of the interfacial boundary conditions in general and the partially bonded and partially un-bonded coupling conditions in particular, will be discussed. The sensitivity to variations in the contact, both area and location will be illustrated, in order to increase the level of understanding in the modelling of the trim components, when compared by numerical simulations on a CAE model and a simplified test set-up.

  • 46.
    Nadampalli, Ravi Varma
    et al.
    Daimler AG.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Glandier, Christian
    Daimler AG.
    Modelling and implementation of interface loss models for linear response simulation in a complex structure.2012Conference paper (Refereed)
  • 47.
    Rumpler, Romain
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Efficient Finite Element Approach for Structural-Acoustic Applications including 3D modelling of Sound Absorbing Porous Materials2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the context of interior noise reduction, the present work aims at proposing Finite Element (FE) solution strategies for interior structural-acoustic applications including 3D modelling of homogeneous and isotropic poroelastic materials, under timeharmonic excitations, and in the low frequency range. A model based on the Biot-Allard theory is used for the poroelastic materials, which is known to be very costly in terms of computational resources. Reduced models offer the possibility to enhance the resolution of such complex problems. However, their applicability to porous materials remained to be demonstrated.First, this thesis presents FE resolutions of poro-elasto-acoustic coupled problems using modal-based approaches both for the acoustic and porous domains. The original modal approach proposed for porous media, together with a dedicated mode selection and truncation procedure, are validated on 1D to 3D applications.In a second part, modal-reduced models are combined with a Padé approximants reconstruction scheme in order to further improve the efficiency.A concluding chapter presents a comparison and a combination of the proposed methods on a 3D academic application, showing promising performances. Conclusions are then drawn to provide indications for future research and tests to be conducted in order to further enhance the methodologies proposed in this thesis.

  • 48.
    Rumpler, Romain
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Deü, Jean-Francois
    Conservatoire National de Arts et Metiers.
    Poroelastic modes selection procedure for efficient modelling of poro-acoustic finite element applications2013Conference paper (Refereed)
  • 49.
    Rumpler, Romain
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Deü, Jean-Francois
    Conservatoire des Arts et Metiers.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    A Padé approximant reconstruction scheme for fast resolution of structural-acoustic finite element models including porous materials.2012Conference paper (Refereed)
    Abstract [en]

    In this work, an efficient solution strategy is investigated for the resolution of multi-frequency structural-acoustic problems including 3D modelling of poroelastic materials. The finite element method is used, together with a combination of a modal-based reduction of the poroelastic domain and a Pad´e-based reconstruction approach. It thus takes advantage of the reduced-size of the problem while further improving the computational efficiency by limiting the number of frequency resolutions of the original problem. An adaptive procedure is proposed for the discretization of the frequency range into frequency intervals of reconstructed solution. The validation is presented on a 3D poro-acoustic example.

  • 50.
    Rumpler, Romain
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Deü, Jean-Francois
    Conservatoire des Arts et Metiers.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    A substructuring FE model for structural-acoustic problems with modal-based reduction of poroelastic interface2011In: Proceedings of the 4th International Conference on Computational Methods for Coupled Problems in Science and Engineering, COUPLED PROBLEMS 2011, INT CENTER NUMERICAL METHODS ENGINEERING , 2011Conference paper (Refereed)
12 1 - 50 of 75
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