Search for dissertations about: "multiaxial fatigue"

Showing result 1 - 5 of 15 swedish dissertations containing the words multiaxial fatigue.

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

   Author : Jonas Ringsberg; Chalmers tekniska högskola; []
   Keywords : 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;

   Abstract : 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. READ MORE

4. 2. Defects in E-PBF Ti-6Al-4V and their Effect on Fatigue Behaviour : Characteristics, Distribution and Impact on Life

   Author : Viktor Sandell; Marta-Lena Antti; Pia Åkerfeldt; Thomas Hansson; Hans Andersson; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Defects; Additive Manufacturing; Ti-6Al-4V; Probabilistic Modelling; Fatigue; Materialteknik; Engineering Materials;

   Abstract : Layer by layer manufacturing (additive manufacturing, AM) of metals is emerging as an alternative to conventional subtractive manufacturing with the goal of enabling near net-shape production of complex part geometries with reduced material waste and shorter lead times. Recently this field has experienced rapid growth through industrial adaptation but has simultaneously encountered challenges. READ MORE

5. 3. Defects and Surfaces and their Impact on Fatigue Behaviour of Powder Bed Fused Ti-6Al-4V : Characteristics and Modelling

   Author : Viktor Sandell; Marta-Lena Antti; Pia Åkerfeldt; Thomas Hansson; Stefano Beretta; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Defects; Additive Manufacturing; Ti-6Al-4V; Probabilistic Modelling; Fatigue; Extreme Value Statistics; Materialteknik; Engineering Materials;

   Abstract : Additive manufacturing (AM), of metals is gaining popularity as an alternative to conventional manufacturing techniques such as casting and forging. Metal-AM allows for the production of complex part geometries with reduced material waste and shorter lead times. READ MORE

6. 4. Influence of combined thermal and mechanical loadings on pearlitic steel microstructure in railway wheels and rails

   Author : Dimitrios Nikas; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Low cycle fatigue LCF ; Wheel steels; Hardness; TEM; Thermal effects; EBSD; Rail steels; Pearlite; Multiaxial fatigue; Spheroidisation; Materials Science;

   Abstract : One of the most important aspects in railway operation is the interaction between rail and wheel. The contact patch between these two components is around the size of a small coin, and since high loads act on this small area, stresses will give rise to wear and damage in both components. READ MORE

7. 5. A study on contact fatigue mechanisms

   Author : Bo Alfredsson; KTH; []
   Keywords : contact fatigue mechanism; spall; spalling; surface crakc; sub-surface crack; elesto-plastic indentation; contact compliance measurement; TECHNOLOGY; TEKNIKVETENSKAP;

   Abstract : Surfaces subjected to rolling and sliding contacts maysuffer from contact fatigue. This thesisdeals with solidmechanic aspects of contact fatigue including the descriptionand verificationof explaining mechanisms. The new mechanism forsurface initiated contact fatigue is basedon tensile surfacestresses from local asperity contacts. READ MORE