Sökning: "creep"

Visar resultat 1 - 5 av 202 avhandlingar innehållade ordet creep.

  1. 1. Creep Behavior of High Temperature Cast Materials for Exhaust Applications

    Författare :Christian Öberg; Stefan Jonsson; Baohua Zhu; John Hald; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; Creep; creep behaviour; creep damage; ductile cast iron; high-alloyed austenitic cast steel; thermal cycling; tensile testing; stress relaxation; oxidation; precipitation.; Materials Science and Engineering; Teknisk materialvetenskap;

    Sammanfattning : This thesis focuses on creep of four cast materials intended for exhaust manifolds in heavy-duty truck engines. Two of the materials are ferritic ductile cast irons, SiMo51 and SiMo1000, one is an austenitic ductile cast iron, D5S, and another one is an austenitic cast steel, HK30. LÄS MER

  2. 2. Mechanical Properties of Welds at Creep Activation Temperatures

    Författare :Henrik C.M. Andersson-Östling; Rolf Sandström; Kamran Nikbin; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; creep; creep crack propagation; OFHC copper; welds; nuclear waste disposal; creep modeling; Materials science; Teknisk materialvetenskap;

    Sammanfattning : Welds in materials intended for service at temperatures above the creep activation temperature often develop damage before the base metal. The weld is a discontinuity in the material and stresses and strains often accumulate in the weld. Knowledge of the properties of the weld is essential to the safe operation of the component containing the weld. LÄS MER

  3. 3. Numerical simulation of weldment creep response

    Författare :Peter Segle; KTH; []
    Nyckelord :ABAQUS; constraint effect; continuum damage mechanics; creep; creep crack growth; design; design code;

    Sammanfattning : In-service inspections of high temperature pressureequipment show that weldments are prone to creep and fatiguedamage. It is not uncommon that severely damaged weldments arefound even before the design life of the component has beenreached. LÄS MER

  4. 4. Oxidation, Creep and Fatigue Synergies in Cast Materials for Exhaust Manifolds

    Författare :Shengmei Xiang; Joakim Odqvist; Baohua Zhu; Stefan Jonsson; Johan Ahlström; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fatigue; low-cycle fatigue; fatigue in an inert atmosphere; fatigue in a synthetic diesel exhaust atmosphere; corrosion-fatigue; creep-fatigue; high-temperature corrosion; high-temperature fatigue; synergistic effect; corrosion-fatigue synergy; creep-fatigue synergy; high-temperature alloys; fatigue damage; creep-fatigue damage; corrosion-fatigue damage; ductile cast iron; high-alloyed austenitic cast steel; thermal cycling; precipitation; aging.; Materials Science and Engineering; Teknisk materialvetenskap;

    Sammanfattning : The future development of engines of heavy-duty vehicles towards reduced CO2 emission will increase the exhaust gas temperature and render the exhaust atmosphere more corrosive. The current service material of exhaust gas components - a ferritic ductile cast iron called SiMo51 - will soon meet its upper-temperature limit. LÄS MER

  5. 5. Concrete creep and thermal stresses : new creep models and their effects on stress development

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

    Sammanfattning : This thesis deals with the problem of creep in concrete and its influence on thermal stress development. New test frames were developed for creep of high performance concrete and for measurements of thermal stress development. Tests were performed on both normal strength and high performance concretes. LÄS MER