Search for dissertations about: "crack mechanics"

Showing result 1 - 5 of 191 swedish dissertations containing the words crack mechanics.

  2. 1. Crack growth paths in rolling contact fatigue — Numerical predictions

    Author : Mohammad Salahi Nezhad; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vector crack tip displacement; Crack face friction; Crack growth direction; Crack propagation; Rolling contact fatigue;

    Abstract : Rolling contact fatigue (RCF) cracks in railway wheels and rails are costly and complex to deal with. Despite the extensive research efforts that have been put into understanding the mechanisms and developing appropriate predictive models for RCF crack growth, there are still a lot of open questions. READ MORE

  4. 2. Fatigue life extension in existing steel bridges. High-Frequency Mechanical Impact treatment and Tungsten Inert Gas remelting in life extension and fatigue crack repair of welded steel structures

    Author : Hassan al-Karawi; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HFMI; TIG-dressing; Life extension; Post weld treatment; Gain factor; Linear elastic fracture mechanics; Crack retrofiting; Peening; fatigue crack; Crack detection; Microhardness; Concentration factor; LEFM; TIG-remelting; Strain gauge;

    Abstract : This thesis investigates the performance of improved welds with two post-weld treatment methods for application on existing structures. High-Frequency Mechanical Impact (HFMI) treatment and Tungsten Inert Gas (TIG) remelting were used for fatigue life extension of welded structures. READ MORE

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

    Author : Pär Ljustell; Fred L. Nilsson; Bo Alfredsson; Gunnar Härkegård; KTH; []
    Keywords : 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;

    Abstract : 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. READ MORE

  6. 4. Modelling of TMF Crack Growth in Polycrystalline Gas Turbine Alloys : Accounting for Crack Closure Effects

    Author : Jordi Loureiro-Homs; Kjell Simonsson; Robert Eriksson; Daniel Leidermark; Tomas Månsson; Linköpings universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : The main objective of the work presented in this Licentiate of Engineering thesis is to investigate and model the fatigue crack propagation behaviour of the nickel-based superalloy Inconel 792, with special attention to the industrial lifing of high-temperature components. In-phase (IP) crack propagation tests have been performed at different temperatures and loading regimes, including extended hold times. READ MORE

  7. 5. On crack growth under compressive stresses

    Author : Per Isaksson; Mittuniversitetet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ph.D. Thesis; Fracture mechanics; Cellulose and paper engineering; Cellulosa- och pappersteknik; Hållfasthetslära;

    Abstract : This thesis concerns fractures subjected to compressive stresses. In the four papers appended fracture behavior in brittle as well as ductile materials is studied. READ MORE