Sökning: "crack mechanisms"

Visar resultat 1 - 5 av 112 avhandlingar innehållade orden crack mechanisms.

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

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

   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

3. 2. Crack growth in single crystal gas turbine blade alloys under service-like conditions

   Författare :Frans Palmert; Johan Moverare; David Gustafsson; Mikael Segersäll; Philippa A.S. Reed; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Single crystal superalloy; TMF; Crack growth; Crystallographic crack growth; Aging; Hold time; Creep crack growth;

   Sammanfattning : This work concerns the fatigue crack growth behaviour of nickel base single crystal superalloys. The main industrial application of this class of materials is in gas turbine blades, where the ability to withstand severe mechanical loading in combination with high temperatures is required. LÄS MER

4. 3. Contact fatigue and crack propagation studies of sintered PM steel

   Författare :Anders Holmberg; Åsa Kassman Rudolphi; Urban Wiklund; Johan Ahlström; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tribology; PM steel; Fatigue; Crack Initiation; Crack Propagation; Material Analysis; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

   Sammanfattning : Gears made of PM steel are of interest for the automotive industry because from the press/sinter route, complex geometries can be produced to near net shape with only a few processing steps while keeping the material and energy usage at a minimum. However, the PM steels of today have significant performance limitations caused by the inherent porosity which impairs the mechanical properties by acting as stress raisers in the material. LÄS MER

5. 4. Failure of thermal barrier coatings under thermal and mechanical fatigue loading : microstructural observations and modelling aspects

   Författare :Håkan Brodin; Anette M. Karlsson; Linköpings universitet; []
   Nyckelord :thermal barrier coating; TBC; delamination; crack initiation; crack propagation; crack growth; oxidation; alumina; spinel; MCrAIY; diffusion; fatigue; modelling; modeling; degradation; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : Industrial and air-borne gas turbine hot components suffer from creep, oxidation, corrosion and microstructural degradation if not shielded from the hot and aggressive combustion gases. Two major strategies commercially available are adopted; film cooling by pressurised air and application of protective coatings. LÄS MER

7. 5. Thermo-mechanical Fatigue Crack Propagation in Inconel 718

   Författare :Lars Jacobsson; Materialteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; crack closure; image analysis; potential drop; in-situ scanning elecron microscopy; crack propagation experiments; Thermo-mechanical fatigue; Inconel 718;

   Sammanfattning : Thermo-mechanical fatigue crack propagation in Inconel 718 has been studied with different methods. In-situ observations with a scanning electron microscope (SEM) were performed, the crack propagation process was followed cycle by cycle and the influences from load, temperature, and microstructure on the crack growth were analyzed. LÄS MER