Sökning: "Structural-acoustics"

Hittade 4 avhandlingar innehållade ordet Structural-acoustics.

  1. 1. Acoustic excitation and transmission of lightweight structures

    Författare :Jonas Brunskog; Teknisk akustik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; point mobility; Lamb waves; wood.; Building construction; plate excitation; cavities; near-periodicity; nearly periodic; sound insulation; timber; structural acoustics; spatial Fourier transform; resilient device; prediction model; periodic; lightweight; ISO tapping machine; airborne noise; Building acoustics; impact noise; Byggnadsteknik;

    Sammanfattning : In order to increase our knowledge of the sound transmission and radiation processes of lightweight wall and floor structures, theoretical models are needed. Detailed models may form a valuable tool. In lightweight floor structures, impact sound insulation is perhaps the most important property to consider. LÄS MER

  3. 2. Structure-acoustic analysis; finite element modelling and reduction methods

    Författare :Peter Davidsson; Byggnadsmekanik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mechanical engineering; hydraulics; vacuum technology; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik; low frequency range; building acoustics; lightweight structures; porous materials; modal reduction; substructuring; finite element analysis; structural acoustics; vibroacoustics; Structural dynamics;

    Sammanfattning : This thesis investigates structure-acoustic systems by use of finite element analysis. The systems studied here are limited to those that consist of an enclosed acoustic fluid cavity, which is coupled to a flexible structure and/or a porous sound absorbing material domain. LÄS MER

  4. 3. Efficient Finite Element Approach for Structural-Acoustic Applications including 3D modelling of Sound Absorbing Porous Materials

    Författare :Romain Rumpler; Peter Göransson; Jean-François Deü; Henry Rice; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Noise reduction; Poroelastic materials; Reduced model; Component mode synthesis; Padé approximants; Structural-acoustics; Finite element method; Fluid-structure interaction.; Matériaux poroélastiques; Modèles réduits; Sous-structuration dynamique; Approximants de Padé; Vibroacoustique interne; Eléments finis; Interaction fluid-structure.; Järnvägsgruppen - Ljud och vibrationer; Järnvägsgruppen - Ljud och vibrationer;

    Sammanfattning : 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. LÄS MER

  5. 4. Frequency Domain Linearized Navier-Stokes Equations Methodology for Aero-Acoustic and Thermoacoustic Simulations

    Författare :Wei Na; Gunilla Efraimsson; Susann Boij; Martinez Lera Paula; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Linearized Navier-Stokes Equations; frequency domain; fluid equivalent model; hybrid liner; thermoacoustic instabilities; Rijke-tube; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : The first part of the thesis focuses on developing a numerical methodology to simulate the acoustic properties of a hybrid liner consisting of a perforated plate, a porous layer and a Helmholtz cavity. Liners are always a standard way to reduce noise in today’s aeroengines, e.g. LÄS MER