Search for dissertations about: "crack propagation"

Showing result 1 - 5 of 163 swedish dissertations containing the words crack propagation.

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

    Author : Jonas Ringsberg; Chalmers University of Technology; []
    Keywords : variable amplitude; crack closure; rolling contact fatigue; crack propagation; railway rails; damage accumulation; critical plane approach; crack initiation; plasticity; multiaxial fatigue;

    Abstract : 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. READ MORE

  2. 2. Thermo-mechanical Fatigue Crack Propagation in Inconel 718

    Author : Lars Jacobsson; Materialteknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; crack closure; image analysis; potential drop; in-situ scanning elecron microscopy; crack propagation experiments; Thermo-mechanical fatigue; Inconel 718;

    Abstract : Thermo-mechanical fatigue crack propagation in Inconel 718 has been studied with different methods. In-situ observations with a scanning electron microscope (SEM) were performed, the crack propagation process was followed cycle by cycle and the influences from load, temperature, and microstructure on the crack growth were analyzed. READ MORE

  3. 3. Numerical simulation of crack propagation and wear in rails

    Author : Jim Brouzoulis; Chalmers University of Technology; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wear; Rolling Contact Fatigue; crack propagation; railway mechanics;

    Abstract : This thesis is concerned with rail deterioration due to Rolling Contact Fatigue (RCF) and wear. Focus lies primarily on numerical modelling and prediction, with the long-term objective of developing tools to be used for specifications and planning of rail maintenance. READ MORE

  4. 4. Modelling of large deformation crack propagation based on the extended finite element method

    Author : Martin Fagerström; Chalmers University of Technology; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; crack propagation; strong discontinuities; material crack driving force; FEM; cohesive zone;

    Abstract : This thesis is concerned with the finite element modelling of large deformation crack propagation, based on the extended finite element methodology. The benefit from this approach is the possibility of locally enriching the finite element space, i.e. to add a priori knowledge about the local behaviour of the solution in order to improve accuracy. READ MORE

  5. 5. Fatigue of Spot Welded Joints: Experiments and Life Predictions

    Author : Hans-Fredrik Henrysson; Chalmers University of Technology; []
    Keywords : crack closure; crack propagation; crack initiation; finite element method; damage accumulation; variable amplitude; fracture mechanics; fatigue; spot welds;

    Abstract : Methods to assess the fatigue strength of spot welds in built-up structures are used on a daily basis in the automotive industry. Efficient and reliable numerical methods make it possible to achieve designs with low weight, low manufacturing costs and good durability within short development cycles, since the number of prototypes built can be reduced. READ MORE