Search for dissertations about: "Random railway"

Showing result 1 - 5 of 11 swedish dissertations containing the words Random railway.

  2. 1. Random railways and cycles in random regular graphs

    Author : Hans Garmo; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Random railway; connectivity number; random regular graph; long cycles; asymptotic distribution. 1991 Mathematics Subject Classification. Primary 60F05; 60C05; 05C38; 05C80; 05C40; 05C45; MATEMATIK; MATHEMATICS; MATEMATIK; matematisk statistik; Mathematical Statistics;

    Abstract : In a cubic multigraph certain restrictions on the paths are made to define what is called a railway. Due to these restrictions a special kind of connectivity is defined. As the number of vertices tends to infinity, the asymptotic probability of obtaining an, in this sense, connected random cubic multigraph is shown to be 1/3. READ MORE

  4. 2. Improving the Dynamic Design Philosophy of High-Speed Railway Bridges Using Reliability-Based Methods

    Author : Reza Allahvirdizadeh; Raid Karoumi; Andreas Andersson; Christoph Adam; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High-speed railway bridges; Bridge dynamics; Running safety; Passenger comfort; Structural reliability; Surrogate models; Active learning; Reliability-based design optimization; Partial safety calibration; Epistemic uncertainties; Höghastighetsjärnvägsbroar; Brodynamik; Trafiksäkerhet; Passagerarkomfort; Konstruktioners tillförlitlighet; Surrogatmodeller; Aktivt lärande; Tillförlitlighetsbaserad optimering; Kalibrering av partialkoefficienter; Epistemiska osäkerheter; Bro- och stålbyggnad; Structural Engineering and Bridges;

    Abstract : Modern railway infrastructures, especially bridges, are exposed to significant vibrations with potential safety implications. In this context, previous studies have shown the inconsistency and inadequacy of some conventional design methods necessitaing them to be improved. The assessment of safety inherently deals with uncertainties. READ MORE

  5. 3. On cyclic accumulation models for degradation of railway foundations

    Author : Hossein Tahershamsi; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Natural soft clay; Global Sensitivity Analysis; Sobol method; Experimental design; Rate-dependent models; Cyclic accumulation models; Cyclic degradation; Uncertainty analysis;

    Abstract : The degradation of railway foundations due to the repeated loading of traffic induces maintenance and safety obligations for the track operator. One major contributor to track degradation is the accelerated settlement rates in soft soils below the track that lead to alignment issues, especially at stiffness transitions. READ MORE

  6. 4. Wheels, Rails and Insulated Joints - Damage and Failure Probability at High Speed and Axle Load

    Author : Johan Sandström; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rail breaks; probability; railway mechanics; contact mechanics; insulated joints; defects; fatigue;

    Abstract : The thesis deals with some fatigue related problems in railway mechanics related to increased axle loads and speeds. The focus is on defects and discontinuities in the wheel--rail system that affect the risk of fatigue and fracture of railway components such as wheels, rails and insulated joints. READ MORE

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

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

    Abstract : 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. READ MORE