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Visar resultat 1 - 5 av 43 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Vibrations in solids : From first principles lattice dynamics to high temperature phase stability

    Författare :Nina Shulumba; Magnus Odén; Igor Abrikosov; Frank Mücklich; Matteo Calandra; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : In this thesis I introduce a new method for calculating the temperature dependent vibrational contribution to the free energy of a substitutionally disordered alloy that accounts for anharmonicity at high temperatures. This method exploits the underlying crystal symmetries in an alloy to make the calculations tractable. LÄS MER

  3. 2. High Frequency Tyre Vibrations

    Författare :Patrik Andersson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; local deformation; adhesion; tyre model; air pumping; parameter study; tyre road noise; tyre road prediction models; tyre noise;

    Sammanfattning : High frequency (above 1 kHz) noise generation from the tyre/road interaction is still not fully understood and accurately modelled.Two noise generation mechanisms previously suggested in the literature are reviewed: air pumping and noise generation cased by adhesive effects between the tyre tread and road surface. LÄS MER

  4. 3. Numerics of Elastic and Acoustic Wave Motion

    Författare :Kristoffer Virta; Gunilla Kreiss; Anders Petersson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite differences; stability; high order accuracy; elastic wave equation; acoustic wave equation; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : The elastic wave equation describes the propagation of elastic disturbances produced by seismic events in the Earth or vibrations in plates and beams. The acoustic wave equation governs the propagation of sound. LÄS MER

  5. 4. Spectra and Dynamics of Excitations in Long-Range Correlated Structures

    Författare :Lars Kroon; Rolf Riklund; Magnus Johansson; Jeroen Lamb; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quasicrystals; deterministic aperiodic superlattices; Markov chains; electronic structure and diffusion; elastic vibrations; Fraunhofer diffraction; discrete solitons; phase transitions; Condensed matter physics; Kondenserade materiens fysik;

    Sammanfattning : Vad karaktäriserar en kristall? Svaret på denna till synes enkla fråga blir kanske att det är en anordning av atomer uppradade i periodiska mönster. Så ordnade strukturer kan studeras genom att det uppträder så kallade Braggtoppar i röntgendiffraktionsmönstret. LÄS MER

  7. 5. Dynamic Plate and Shell Equations Using Power Series Expansions - Applications Including Elasticity, Poroelasticity and Fluid Loading

    Författare :Anders Hägglund; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; approximate boundary conditions; series expansion; Biot equations; vibrations; cylindrical shell; dispersion curves; plate theory; thin shells; porous plate;

    Sammanfattning : Thin structures are used in a wide range of engineering applications. The subject of this thesis is the derivation of approximate equations for the dynamics of thin plates and shells using series expansion methods. LÄS MER