Sökning: "crack initiation"

Visar resultat 6 - 10 av 147 avhandlingar innehållade orden crack initiation.

1. 6. 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. 7. 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

4. 8. Fatigue life prediction of additively manufactured ductile nickel-based superalloys : Constitutive and crack initiation modelling

   Författare :Thomas Lindström; Daniel Leidermark; Kjell Simonsson; Robert Eriksson; Magnus Ekh; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Additive manufacturing; Low-cycle fatigue; Thermomechanical fatigue; Constitutive modelling; Anisotropy;

   Sammanfattning : This dissertation was produced at the Division of Solid Mechanics at Linköping University, and is the final result of a project that included mechanical testing and modelling of an additively manufactured ductile nickel-based superalloy.The main objective of the work presented in this thesis was to investigate and model the cyclic behaviour and the fatigue life behaviour of an additively manufactured ductile nickel-based superalloy, with emphasis on modelling the stabilised material behaviour, by which fatigue life predictions can be based upon. LÄS MER

5. 9. Predicting shear type crack initiation and growth in concrete with non-linear finite element method

   Författare :Richard Malm; Håkan Sundquist; Anders Ansell; Kent Gylltoft; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; non-linear finte element analysis; concrete; crack width; crack propagation; shear; Building engineering; Byggnadsteknik;

   Sammanfattning :   In this thesis, the possibility to numerically describing the behaviour that signifies shear type cracking in concrete is studied. Different means for describing cracking are evaluated where both methods proposed in design codes based on experiments and advanced finite element analyses with a non-linear material description are evaluated. LÄS MER

7. 10. Crystal plasticity and crack initiation in a single-crystal nickel-base superalloy : Modelling, evaluation and applications

   Författare :Daniel Leidermark; Kjell Simonsson; Johan Moverare; Sören Sjöström; Hannu Hänninen; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Single-crystal superalloy; Crystal plasticity; Fatigue crack initiation; Critical plane model; Theory of critical distance; Rafting; Tension compression asymmetry;

   Sammanfattning : In this dissertation the work done in the projects KME-410/502 will be presented.The overall objective in these projects is to evaluate and develop tools for designingagainst fatigue in single-crystal nickel-base superalloys in gas turbines. LÄS MER