Sökning: "Elastic waves"

Visar resultat 1 - 5 av 56 avhandlingar innehållade orden Elastic waves.

  1. 1. Transmission of waves through elastic and viscoelastic junctions

    Författare :Tomas Nygren; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Wave; elastic; viscoelastic; extensional; characteristic impedance; junction; transmission; reflection; dissipation; optimisation; Materialvetenskap; Materials science; Teknisk materialvetenskap; Solid Mechanics; hållfasthetslära;

    Sammanfattning : Transmission of extensional waves through elastic and viscoelastic junctions between elastic and collinear bars have been studied theoretically and experimentally. The models used can be interpreted also for other types of waves (e.g. dilatational waves, shear waves, electromagnetic waves) and systems. LÄS MER

  3. 2. Modelling tools for quieter vehicles : Waves in poro– and visco–elastic continua

    Författare :Martin Östberg; Leif Kari; Jenny Jerrelind; Sergey Sorokin; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vibro-acoutics; poro-elastic; visco-elastic; reduced models; Harmonic expansion; wave guide;

    Sammanfattning : New modelling tools intended to contribute to the development of components for quieter vehicles are developed. The tools are based on continuum models for wave propagation in poro– and visco–elastic media. By using geometric attributes of the studied components, the computational cost may be radically decreased compared to traditional methods. LÄS MER

  4. 3. Thin Layers in Elastic Wave Propagation -Effective Modelling and Diffraction

    Författare :Peter Bövik; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Geometrical Theory of Diffraction; elastic wave scattering; shear waves; Wienr-Hopf method; L-TV waves; applications;

    Sammanfattning : In the present thesis, the interest is focussed on the problem of effective modelling of thin interface layers for applications in elastic wave scattering. The layers are considered to be thin compared with wavelengths involved and it is shown that when all effects to lowest order in the layer thickness are included, we get boundary conditions (BCs) which have a number of nice features, including the one of implying that no scattering occurs when the layer has material parameters identical to the ones in the matrix medium. LÄS MER

  5. 4. Waves and instabilities through the lens of asymptotic analysis

    Författare :Anthony Bonfils; John Wettlaufer; Dhrubaditya Mitra; Woosok Moon; Jerome Neufeld; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; waves; wrinkles; instabilities; Theoretical Physics; teoretisk fysik;

    Sammanfattning : Understanding the interaction of water waves with winds and marine currents is a fundamental problem in geophysical fluid dynamics. From the point of view of hydrodynamic stability, surface waves are regarded as perturbations of an inviscid parallel shear flow modeling the wind in the air and the current in the water. LÄS MER

  7. 5. Direct and inverse resonance problems for seismic surface waves

    Författare :Samuele Sottile; Matematik (naturvetenskapliga fakulteten); []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Inverse problems; Resonances; Spectral theory; Love waves; Rayleigh waves;

    Sammanfattning : This thesis concerns the investigation of direct and inverse resonance results for the Love and the Rayleigh operators, which arise from decoupling the three-dimensional elastic wave equation in the semiclassical limit in the half-space. Direct resonance results in terms of the asymptotic distribution of resonances in the complex plane are obtained for the Love and the Rayleigh operators. LÄS MER