Sökning: "cracks"

Visar resultat 6 - 10 av 468 avhandlingar innehållade ordet cracks.

  1. 6. 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

  3. 7. Life Prediction and Mechanical Behavior of Thermal Barrier Coatings

    Författare :Yan Liu; Materialteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Stress intensity factors; Macro-cracks; Micro-cracks; Mechanical behaviour; Thermal barrier coatings; Life prediction; Material technology; Materiallära; materialteknik;

    Sammanfattning : Delamination and spallation of thermal barrier coating (TBC) systems, used in hot parts of gas turbines, have been studied with respect to thermal fatigue. TBCs with and without pre-existing cracks were investigated. Thermal shock tests were performed until coating spallation. LÄS MER

  4. 8. Closed-die forging and slab hot rolling with focus on material yield : some industrial problems analysed by FEM

    Författare :Esa Ervasti; Ulf Ståhlberg; Hans Keife; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Material yield; Closed-die forging; Hot rolling; Cracks; Macro-inclusions; Steel; FEM; Industrial engineering and economy; Industriell teknik och ekonomi;

    Sammanfattning : The thesis is focussed on improving the material yield in closed-die forging and rolling. The former is restricted to the manufacturing of heavy crown wheels and front axle beams and the latter to the hot rolling of steel slabs. To enhance the yield the commercial FE-codes Form2D and Dyna3D are used. LÄS MER

  5. 9. Steel fibre corrosion in cracks : durability of sprayed concrete

    Författare :Erik Nordström; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Structural Engineering; Konstruktionsteknik;

    Sammanfattning : Steel fibre reinforced sprayed concrete is common practice for permanent linings in underground construction. Today there is a demand on "expected technical service life" of 120 years. Thin steel fibres could be expected to discontinue carrying load fast with a decrease of fibre diameter caused by corrosion, especially in cracks. LÄS MER

  7. 10. Durability of sprayed concrete : steel fibre corrosion in cracks

    Författare :Erik Nordström; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Structural Engineering; Konstruktionsteknik;

    Sammanfattning : A combination of sprayed concrete technique and steel fibre technology gives obvious advantages when saving the work needed to place conventional reinforcement. In rock strengthening applications this is most accentuated. Sprayed concrete in general, made by skilled workmen, will generally be of high quality and good durability. LÄS MER