Sökning: "frequency response functions."

Visar resultat 21 - 25 av 96 avhandlingar innehållade orden frequency response functions..

  1. 21. Transmission line theory for cable modeling: a delay-rational model based on Green's functions

    Författare :Maria De Lauretis; Sven Nordebo; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Industriell elektronik; Industrial Electronics;

    Sammanfattning : At present, induction motors are controlled via the so-called variable-frequency drives (VFD) that allow to control the speed for the motors. The purpose of this PhD thesis is to improve electromagnetic modeling techniques for the study of conducted electromagnetic emissions in variable-frequency drives, with the aim of enhancing their reliability in energy production plants. LÄS MER

  3. 22. Development of new techniques for the numerical modelling of railway track dynamics. Application to rolling noise assessment

    Författare :Blas Blanco; Leif Kari; Ernesto García-Vadillo; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Track modelling; Timoshenko element; local deformation; distributed supports; moving Green s functions; rolling noise;

    Sammanfattning : The numerical modelling is widely employed for the prediction of the railway track dynamic behaviour, which is of utmost importance for the characterisation of the undesired medium-high frequency phenomena, such as corrugation, wheel-out-of-roundness and noise emission. This study is devoted to the improvement of railway track numerical modelling, the efficient resolution of the problem in the time domain and the assessment of rolling noise for different approaches of the track modelling. LÄS MER

  4. 23. Fractional Calculus and Linear Viscoelasticity in Structural Dynamics

    Författare :Mikael Enelund; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; linear viscoelasticity; convolution integrals; anisotropy; structural modeling; finite elements; material damping; time integration; internal variables; relaxation; fractional calculus; creep; Mittag-Leffler functions;

    Sammanfattning : The use of linear viscoelasticity together with fractional calculus in time-domain structural modeling is studied. Both constitutive and structural aspects are investigated. LÄS MER

  5. 24. Viscoelastic Materials : Identification and Experiment Design

    Författare :Agnes Rensfelt; Torsten Söderström; Händel Peter; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; viscoelastic materials; complex modulus; system identification; optimal experiment design; distributed parameter systems; frequency domain identification; wave propagation; Automatic control; Reglerteknik; Elektroteknik med inriktning mot reglerteknik; Electrical Engineering with specialization in Automatic Control;

    Sammanfattning : Viscoelastic materials can today be found in a wide range of practical applications. In order to make efficient use of these materials in construction, it is of importance to know how they behave when subjected to dynamic load. LÄS MER

  7. 25. Untangling Cortico-Striatal Circuitry and its Role in Health and Disease - A computational investigation

    Författare :Jovana Belic; Jeanette Hellgren Kotaleski; Arvind Kumar; Abigail Morrison; Arthur Leblois; KTH; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; cortico-striatal circuits; levodopa-induced dyskinesia; Parkinson’s disease; effective connectivity; cross-frequency coupling; corticostriatal network; network oscillations; GABAergic transmission. basal ganglia; striatum; cortex; fast spiking interneurons; medium spiny neurons; neuronal avalanches;

    Sammanfattning : The basal ganglia (BG) play a critical role in a variety of regular motor and cognitive functions. Many brain diseases, such as Parkinson’s diseases, Huntington’s disease and dyskinesia, are directly related to malfunctions of the BG nuclei. LÄS MER