Sökning: "variable amplitude fatigue"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden variable amplitude fatigue.

  1. 1. The Influence of Residual Stresses on Constant and Variable Amplitude Fatigue Behaviour of Steel

    Författare :Kamellia Dalaei; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Steel; Relaxation; Residual stress; Variable Amplitude; Shot peening; Fatigue;

    Sammanfattning : Subjected to dynamic loading, truck components are exposed to variable amplitude fatigue. The fatigue life of components is to a large degree controlled by the behaviour of the surface zones. LÄS MER

  3. 2. Fatigue of Spot Welded Joints: Experiments and Life Predictions

    Författare :Hans-Fredrik Henrysson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; crack closure; crack propagation; crack initiation; finite element method; damage accumulation; variable amplitude; fracture mechanics; fatigue; spot welds;

    Sammanfattning : 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. LÄS MER

  4. 3. Fatigue improvement of steel bridges with high-frequency mechanical impact treatment

    Författare :Poja Shams Hakimi; Chalmers tekniska högskola; []
    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; HFMI; thickness effect; bridge; steel; variable amplitude; fatigue;

    Sammanfattning : This thesis investigates the performance of fatigue-improved welds with high-frequency mechanical impact (HFMI) for application on new bridges. Fatigue strength improvement with HFMI can enable lightweight design of bridges and allow the utilisation of the benefits of high-strength steels. LÄS MER

  5. 4. Fatigue crack growth experiments and analyses - from small scale to large scale yielding at constant and variable amplitude loading

    Författare :Pär Ljustell; Fred L. Nilsson; Bo Alfredsson; Gunnar Härkegård; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fracture mechanics; fatigue crack growth; finite elements analysis; small scale yielding SSY ; large scale yielding LSY ; low cycle fatigue LCF ; crack tip opening displacement CTOD ; crack closure; potential drop method; constant amplitude load; variable amplitude load; inconel 718; stainless steel 316L;

    Sammanfattning : This thesis is on fatigue crack growth experiments and assessments of fatigue crack growth rates. Both constant and variable amplitude loads in two different materials are considered; a nickel based super-alloy Inconel 718 and a stainless steel 316L. LÄS MER

  7. 5. Rolling Contact Fatigue of Railway Rails with Emphasis on Crack Initiation

    Författare :Jonas Ringsberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; variable amplitude; crack closure; rolling contact fatigue; crack propagation; railway rails; damage accumulation; critical plane approach; crack initiation; plasticity; multiaxial fatigue;

    Sammanfattning : Increased traffic density and the heavier axle loads of modern trains have led to severe problems with rolling contact fatigue (RCF) which cause initiation of surface cracks in railheads. In this thesis, a specific type of surface crack, the head check, is studied numerically with emphasis on fatigue crack initiation. LÄS MER