Sökning: "Crack"

Visar resultat 1 - 5 av 519 avhandlingar innehållade ordet Crack.

  1. 1. Crack-junctions : Bridging the gap between nano electronics and giga manufacturing

    Författare :Valentin Dubois; Göran Stemme; Christofer Hierold; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; nanotechnology; nanoelectronics; nanogap electrodes; molecular electronics; nanoplasmonics; crack-junctions; break junctions; nanowires; parallel fabrication; lithography; fracture; crack; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Obtaining both nanometer precision of patterning and parallel fabrication on wafer-scale is currently not possible in conventional fabrication schemes. Just as we are looking beyond semiconductor technologies for next-generation electronics and photonics, our efforts turn to new ways of producing electronic and photonic interfaces with the nanoscale. LÄS MER

  3. 2. High Strain Fatigue Crack Growth and Crack Closure

    Författare :Michael Andersson; Materialteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; materialteknik; Materiallära; Material technology; crack closure; high strain fatigue; crack grotwh;

    Sammanfattning : Understanding of the growth of fatigue cracks is of utmost importance since such growth often has a profound influence on the life of components subjected to cyclic loading. Thus, reliable fatigue life models enable a more efficient use of materials and improve the performance and efficiency in many applications. LÄS MER

  4. 3. Crack growth paths in rolling contact fatigue — Numerical predictions

    Författare :Mohammad Salahi Nezhad; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; Vector crack tip displacement; Crack face friction; Crack growth direction; Rolling contact fatigue; Crack propagation;

    Sammanfattning : 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. LÄS MER

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

    Författare :Jonas Ringsberg; Chalmers University of Technology; []
    Nyckelord :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

  7. 5. 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

    Författare :Hassan al-Karawi; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 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;

    Sammanfattning : 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. LÄS MER