Sökning: "RCF"

Visar resultat 16 - 20 av 37 avhandlingar innehållade ordet RCF.

  1. 16. Effects of top-of-rail friction modifiers on the friction, wear and cracks of railway rails

    Författare :Saad Ahmed Khan; Jan Lundberg; Rolf Dollevoet; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Drift och underhållsteknik; Operation and Maintenance;

    Sammanfattning : The railway is an economical and environmentally friendly mode of transport for long distances and heavy loads. The demands on the operators are increasing with increased competition in the market, and therefore they are currently demanding more track capacity. In the short term, the existing network is expected to deliver the increased capacity. LÄS MER

  3. 17. High Performance Bio-based Composites : Mechanical and Environmental Durability

    Författare :Newsha Doroudgarian; Kristofer Gamstedt; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Polymeric Composite Materials; Polymera konstruktionsmaterial;

    Sammanfattning : The presented work is a part of the ongoing effort on the development of high performance bio-based composites with enhanced durability, under static and dynamic mechanical loading including the exposure to elevated humidity. The impact of relative humidity on the performance of cellulosic fibers (natural and regenerated), bio-based resins and their composites was studied. LÄS MER

  4. 18. Crack growth paths in rolling contact fatigue — Numerical predictions

    Författare :Mohammad Salahi Nezhad; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vector crack tip displacement; Crack face friction; Crack growth direction; Crack propagation; Rolling contact fatigue;

    Sammanfattning : Rolling contact fatigue (RCF) cracks in railway wheels and rails are costly and complex to deal with. Despite the extensive research efforts that have been put into understanding the mechanisms and developing appropriate predictive models for RCF crack growth, there are still a lot of open questions. LÄS MER

  5. 19. Rolling Contact Fatigue of Railway Rails with Emphasis on Crack Initiation

    Författare :Jonas Ringsberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; variable amplitude; crack closure; rolling contact fatigue; crack propagation; railway rails; damage accumulation; critical plane approach; crack initiation; plasticity; multiaxial fatigue;

    Sammanfattning : Increased traffic density and the heavier axle loads of modern trains have led to severe problems with rolling contact fatigue (RCF) which cause initiation of surface cracks in railheads. In this thesis, a specific type of surface crack, the head check, is studied numerically with emphasis on fatigue crack initiation. LÄS MER

  7. 20. Development of hierarchical cellulosic reinforcement for polymer composites

    Författare :Abdelghani Hajlane; Angelika Bachinger; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Polymera konstruktionsmaterial; Polymeric Composite Materials;

    Sammanfattning : Cellulose is an environmentally friendly material which is obtainable in vast quantities, since it is present in every plant. Cellulosic fibers are commercially found in two forms: natural (flax, hemp, cotton, sisal, wood, etc.) and regenerated cellulose fibers (RCF). LÄS MER