Sökning: "cyclic crack propagation"

Visar resultat 1 - 5 av 35 avhandlingar innehållade orden cyclic crack propagation.

1. 1. 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

3. 2. Rolling Contact Fatigue of Railway Rails with Emphasis on Crack Initiation

   Författare :Jonas Ringsberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 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

4. 3. 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

5. 4. A ΔJ approach for nonlinear fatigue crack propagation : Experimental and numerical investigation of a ductile superalloy

   Författare :Daniel Nilsson; Per Almroth; Kjell Simonsson; Björn Sjödin; Daniel Leidermark; Sören Sjöström; Fredrik Borén; Johan Ahlström; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ΔJ; Cyclic J-integral; Fatigue testing; Nickel-based superalloy; Thermo-mechanical fatigue; Elasto-plastic fracture mechanics;

   Sammanfattning : This dissertation is a product of an academic-industrial collaboration between the Division of Solid Mechanics at Linköping University and Siemens Energy AB. The focus is on enhancing the design optimisation procedures for high-temperature components in industrial gas turbines (IGT). LÄS MER

7. 5. Numerical simulation of crack growth and wear in rails

   Författare :Jim Brouzoulis; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; crack propagation; material forces; Rolling Contact Fatigue; wear; railway mechanics;

   Sammanfattning : Wear and rolling contact fatigue (RCF) of rails are huge problems for the railway industry with increased world-wide occurrence during the last decades. It is, therefore, of high interest to develop tools for the prediction of wear and RCF which can be used to estimate rail life. LÄS MER