Sökning: "Fatigue limit"

Visar resultat 1 - 5 av 68 avhandlingar innehållade orden Fatigue limit.

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

   Författare :Shengmei Xiang; Joakim Odqvist; Baohua Zhu; Stefan Jonsson; Johan Ahlström; KTH; []
   Nyckelord :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.; Teknisk materialvetenskap; Materials Science and Engineering;

   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

3. 2. Very high cycle fatigue of high performance steels

   Författare :Vitaliy Kazymyrovych; Karlstads universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fatigue; tool steels; ultrasonic testing; fatigue life; crack growth rate; fatigue mechanisms; Materialteknik; Materials Engineering;

   Sammanfattning : Many engineering components reach a finite fatigue life well above 109 load cycles. Some examples of such components are found in airplanes, automobiles or high speed trains. For some materials the fatigue failures have lately been found to occur well after 107 load cycles, namely in the Very High Cycle Fatigue (VHCF) range. LÄS MER

4. 3. Prediction of the fatigue limit : accuracy of post-processing methods

   Författare :Sven Norberg; Mårten Olsson; Erland Johnson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Other engineering mechanics; Övrig teknisk mekanik;

   Sammanfattning : Several fatigue criteria were evaluated with experimental fatigue test data. The fatigue tests contained many different geometries with different degrees of stress concentration. It was concluded that the differences between the criteria were neglectable when compared to the differences between the specimens. LÄS MER

5. 4. Fatigue of existing steel bridges : Reliability and risk analyses for decision-making

   Författare :Ruoqi Wang; John Leander; Raid Karoumi; Boulent Imam; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fatigue; steel bridges; decision-making; reliability analysis; risk analysis; spatial correlation; system modelling; inspection and maintenance; Utmattning; stålbroar; beslutsfattande; tillförlitlighet; riskanalys; rumslig korrelation; systemmodellering; inspektion och underhåll; Bro- och stålbyggnad; Structural Engineering and Bridges;

   Sammanfattning : Fatigue is one of the primary reasons that limit the service life of steel bridges. Many bridges in Sweden and other countries have progressively approached their anticipated service lives. Since funding and resources are limited, simultaneously replacement or maintenance of bridges is impractical. LÄS MER

7. 5. Very high cycle fatigue of automotive steels : Testing and computation at 20 kHz

   Författare :Mohamed Sadek; Jens Bergström; Nils Hallbäck; Ulrich Krupp; Karlstads universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Very high cycle fatigue; ultrasonic fatigue testing; automotive steels; fatigue strength; stress intensity computation; crack growth; Materialteknik; Materials Engineering;

   Sammanfattning : Mechanical fatigue failure occurs in components subjected to cyclic loading. A crack initiates at critical regions in the component and propagates during repeated loading. The expected fatigue life depends on the level, type and frequency of the loading. LÄS MER