Sökning: "discrete irregularities"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden discrete irregularities.

  1. 1. Modelling of wheel/rail interaction considering roughness and discrete irregularities

    Författare :Astrid Pieringer; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; roughness; non-Hertzian contact; railway noise; vertical wheel rail interaction; time domain; discrete irregularities;

    Sammanfattning : The interaction between wheel and rail is the predominant source of noise emission from railway operations in a wide range of conventional speeds. On the one hand, this wheel/rail noise concerns rolling noise and impact noise caused by the vertical interaction excited by roughness and discrete irregularities of the wheel/rail running surfaces, respectively. LÄS MER

  3. 2. Time-domain modelling of high-frequency wheel/rail interaction

    Författare :Astrid Pieringer; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wheel rail interaction; railway noise; roughness; time domain; frictional instability; discrete irregularities; transient contact; non-Hertzian contact;

    Sammanfattning : The interaction between wheel and rail is the predominant source of noise emission from railway operations in a wide range of conventional speeds. On the one hand, this wheel/rail noise concerns rolling noise and impact noise caused by the vertical interaction excited by roughness and discrete irregularities of the wheel/rail running surfaces, respectively. LÄS MER

  4. 3. Dynamic Train/Track Interaction: Simulation of Railhead Corrugation Growth under a Moving Bogie Using Mathematical Models Combined with Full-Scale Measurements

    Författare :Annika Igeland; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; railhead corrugation growth; railway and track irregularities; railway dynamics and measurements; train track interaction; complex-valued modal analysis;

    Sammanfattning : Heavier trains and higher speeds have increased the need for high-quality tracks and vehicles in order to fulfill safety and environmental requests. The phenomena involved in dynamic train/track interaction lead to noise radiation, induce ground-borne vibrations and degrade the track structure and the railcar wheels. LÄS MER

  5. 4. Electron Transport in Mesoscopic Semiconductor Nanostructures

    Författare :Magnus Persson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis presents results from experimental studies, mostly at very low temperatures, and fabrication of very small electronic components made with GaAs/GaAlAs heterostructures. The components are so small that individual electrons are important to their characteristics. LÄS MER

  7. 5. Influence of wheel tread damage on wheelset and track loading – Field tests and numerical simulations

    Författare :Michele Maglio; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; axle stress; instrumented wheelset; impact loads; dynamic wheel–rail interaction; wheelset maintenance; wheel tread damage;

    Sammanfattning : Wheel tread damage leading to high magnitudes of vertical wheel–rail contact forces is a major cause of train delays in the Swedish railway network, in particular during the coldest months of the year. According to regulations, vehicles generating contact forces exceeding the limit value for allowed wheel–rail impact loads must be taken out of service for wheel maintenance. LÄS MER