Search for dissertations about: "crack propagation"

Showing result 6 - 10 of 187 swedish dissertations containing the words crack propagation.

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

    Author : Martin Fagerström; Chalmers tekniska högskola; []
    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

  4. 7. Fatigue of Spot Welded Joints: Experiments and Life Predictions

    Author : Hans-Fredrik Henrysson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 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

  5. 8. Modelling of ultrasonic scattering from a crack in a pipe

    Author : Jacob Rubenson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Non-Destructive Testing; Cylindrical Geometry; Pipe; Crack; Wave propagation;

    Abstract : This thesis considers elastic wave scattering in an infinitely long cylindrical pipe with an infinitely long internal axial crack. The method used in this thesis is called a hypersingular integral equation method since it starts with an integral representation and by using the Green's tensor of the pipe it can be manipulated to a hypersingular equation for the crack-opening displacement (COD). READ MORE

  6. 9. Failure of thermal barrier coatings under thermal and mechanical fatigue loading : microstructural observations and modelling aspects

    Author : Håkan Brodin; Anette M. Karlsson; Linköpings universitet; []
    Keywords : thermal barrier coating; TBC; delamination; crack initiation; crack propagation; crack growth; oxidation; alumina; spinel; MCrAIY; diffusion; fatigue; modelling; modeling; degradation; TECHNOLOGY; TEKNIKVETENSKAP;

    Abstract : Industrial and air-borne gas turbine hot components suffer from creep, oxidation, corrosion and microstructural degradation if not shielded from the hot and aggressive combustion gases. Two major strategies commercially available are adopted; film cooling by pressurised air and application of protective coatings. READ MORE

  7. 10. Railway Wheel Flats. Martensite Formation, Residual Stresses, and Crack Propagation

    Author : Johan Jergeus; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sliding contact; metallographic investigation; crack propagation; thermal shock; constitutive modelling; phase transformations; railway wheel flats; full-scale field experiments; transformation plasticity; tread damage; residual stresses; spalling; martensite formation;

    Abstract : A railway wheel flat is a flat spot on the rolling surface of a wheel caused by its unintentional sliding on the rail. The reason for the sliding may be poorly adjusted, frozen or defect brakes, or too high braking forces in relation to the available wheel/rail adhesion. READ MORE