Sökning: "sub-surface crack"

Hittade 4 avhandlingar innehållade orden sub-surface crack.

  1. 1. A study on contact fatigue mechanisms

    Författare :Bo Alfredsson; KTH; []
    Nyckelord :contact fatigue mechanism; spall; spalling; surface crakc; sub-surface crack; elesto-plastic indentation; contact compliance measurement; TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : Surfaces subjected to rolling and sliding contacts maysuffer from contact fatigue. This thesisdeals with solidmechanic aspects of contact fatigue including the descriptionand verificationof explaining mechanisms. The new mechanism forsurface initiated contact fatigue is basedon tensile surfacestresses from local asperity contacts. LÄS MER

  3. 2. Fatigue crack initiation and propagation in sandwich structures

    Författare :Magnus Burman; KTH; []
    Nyckelord :TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : The focus throughout this thesis is on the fatigue characteristics of core materials used insandwich structures. Three sandwich configurations are investigated, two with cellular foamsand one with honeycomb core material These corresponds to typical materials and dimensionsused in the marine and aeronautical industry. LÄS MER

  4. 3. Non-destructive measurement of near-surface cracks in railheads : with focus on ultrasonic inspections

    Författare :Rayendra Anandika; Jan Lundberg; Paul Wilcox; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rail inspection; phased array; ultrasonic testing; eddy current testing; surface cracks; non-destructive testing; NDT; railway; condition monitoring; Drift och underhållsteknik; Operation and Maintenance;

    Sammanfattning : Near-surface cracks in railhead that caused by rolling contact fatigue (RCF) is one of a kind rail defects that degrade rail track quality. Dependent on the trail load, the cracks can reach to severe level quickly. LÄS MER

  5. 4. Surface Integrity and Fatigue Performance of Nickel-based Superalloys

    Författare :Zhe Chen; Ru Peng; Johan Moverare; Sten Johansson; Manuel François; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Due to global warming, the demand for more efficient gas turbines has increased. A way to achieve this, is by increasing the operating temperature of the gas turbine. Therefore, nickel-based superalloys have been developed to withstand these extreme temperatures and loads, especially in the hot sections. LÄS MER