Sökning: "causes of defects"

Visar resultat 21 - 25 av 105 avhandlingar innehållade orden causes of defects.

  1. 21. Squat defects and rolling contact fatigue clusters - Numerical investigations of rail and wheel deterioration mechanisms

    Författare :Robin Andersson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rail surface irregularities; rolling contact fatigue clusters; dynamic vehicle–track interaction; rolling contact fatigue; studs; squats; fracture mechanics;

    Sammanfattning : Squat defects, a type of localised rolling contact fatigue damage appearing on rail surfaces with rail break as an ultimate consequence, have concerned infrastructure managers for the last couple of decades. In recent years similar types of defects—so-called studs—that are visually resembling squats, have started to appear. LÄS MER

  3. 22. Fracture Mechanics in Design and Assessment of Existing Structures: Two Case Studies

    Författare :Pourya Noury; Raid Karoumi; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Steel Structures; Stålbyggnad;

    Sammanfattning : In the present thesis, the application of fracture mechanics in design and assessment of steel structures has been studied.The first case study concerns a ring-flange connection used in wind turbine towers. The flange is rolled from straight steel profile into a complete ring. LÄS MER

  4. 23. Very high cycle fatigue of high performance steels

    Författare :Vitaliy Kazymyrovych; Karlstads universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fatigue; tool steels; ultrasonic testing; fatigue life; crack growth rate; fatigue mechanisms; Materialteknik; Materials Engineering;

    Sammanfattning : Many engineering components reach a finite fatigue life well above 109 load cycles. Some examples of such components are found in airplanes, automobiles or high speed trains. For some materials the fatigue failures have lately been found to occur well after 107 load cycles, namely in the Very High Cycle Fatigue (VHCF) range. LÄS MER

  5. 24. Physical properties and structural stability of carbon nanotubes under extreme conditions

    Författare :Maxime Noël; David Dunstan; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Experimentell fysik; Experimental Physics;

    Sammanfattning : Carbon nanotubes (CNTs) have attracted an immense attention of the research community since reporting on this system by S. Ijima in 1991. A "single-walled" CNT (SWCNT) can be considered as a rolled-up single-layer graphene - a one atom-thick layer of carbon atoms arranged in a hexagonal lattice. LÄS MER

  7. 25. Revision Hip Arthroplasty : Impaction Bone Grafting and Low-Dose CT-Based Measurements of Bone Density and Migration

    Författare :Hampus Stigbrand; Gösta Ullmark; Nils Hailer; Per Wretenberg; Uppsala universitet; []
    Nyckelord :Revision Hip Arthroplasty; Bone Grafting; Computed Tomography; Bone Mineral Density; CTMA; Orthopaedics; Ortopedi;

    Sammanfattning : Aseptic loosening of total hip replacements is always associated with bone defects, either due to removal of the existing implant or osteolysis. Bone defects can be handled during revision surgery with impaction bone grafting (IBG). LÄS MER