Search for dissertations about: "fracture propagation"

Showing result 1 - 5 of 100 swedish dissertations containing the words fracture propagation.

  2. 1. Heterogeneous Bonded Particle Modelling of Rock Fracture

    Author : Albin Wessling; Jörgen Kajberg; Simon Larsson; Pär Jonsén; Timo Saksala; Luleå tekniska universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rock; DEM; BPM; fracture; drilling; dynamic; Solid Mechanics; Hållfasthetslära;

    Abstract : The dynamic fracture process of rock materials is of importance for several industries, such as the rock drilling process in geothermal and mining applications. Gaining knowledge and understanding of dynamic rock fracture through numerical simulations can enhance the rock drilling process, for example by optimising the drill bit geometry and drilling parameters. READ MORE

  4. 2. Experiments and modelling of fracture initiation at impact

    Author : Ola Wall; Hållfasthetslära; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vibration and acoustic engineering; vacuum technology; hydraulics; Viscoplasticity; Mechanical engineering; Ductile; Brittle; Dynamic; Fracture; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik; Material technology; Materiallära; materialteknik;

    Abstract : The thesis addresses different questions, each necessary in the understanding of dynamic fracture initiation and crack propagation in steel. Emphasis lays on dynamic crack propagation experiments performed in the ductile to brittle transition region and possible conclusions, that can be drawn from them. READ MORE

  5. 3. Computational modeling of oxygen-assisted fracture in nickel-based superalloys

    Author : Kim Louisa Auth; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Stress-assisted diffusion; Intergranular fracture; Crack growth rate; Crystal plasticity; Moving boundary condition.; Crack propagation; Grain boundaries; Polycrystal;

    Abstract : Nickel-based superalloys are a commonly used material in applications where high strength is required at high temperatures. A typical such example is jet engines and, in the case of polycrystalline nickel-based superalloys, components like turbine disks. READ MORE

  6. 4. Simulation of dynamic instabilities during high rate deformation of ductile bars and plates

    Author : Kristina Nilsson; Mekanik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; numerical simulation; non-linear; wave propagation; multiple necking; necking; buckling; fracture; Mechanical engineering; Maskinteknik; finite elements; cohesive elements; dynamic; J2-flow theory; J2-deformation theory; viscoplastic; background inertia;

    Abstract : In this thesis, some of the phenomena occurring in plates and cylindrical bars subjected to dynamic loading are investigated. Numerical simulations using a dynamic finite element code are performed for a number of different sized specimens with various initial surface imperfections. Typically imposed loading velocities are in the range 10m/s.. READ MORE

  7. 5. Behaviour of fracture process zones in concrete influenced by simultaneously applied normal and shear displacements

    Author : Manouchehr Hassanzadeh; Avdelningen för Byggnadsmaterial; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; softening; mixed mode; fictitious crack model; concrete; deformationer; betong; brottmekanik; hållfasthet; brotthållfasthet; spänningar; skjuvspänningar; sprickor; beräkningsmodeller; brottenergi; teori; laboratorieförsök; interlock; crack path; diagonal crack; microcracking; instability; fracture energy; fracture mechanics; shear; tension; process zone;

    Abstract : The thesis deals with the determination of the post peak behaviour of concrete in pure tension, and combined tension (compression) and shear. A test arrangement has been developed in order to determine the post peak behaviour of concrete expressed as stress - displacement curves. READ MORE