Sökning: "Hold-time fatigue"

Hittade 5 avhandlingar innehållade orden Hold-time fatigue.

1. 1. Modelling of fatigue crack propagation in Inconel 718 under hold time conditions

   Författare :Erik Lundström; Kjell Simonsson; Tomas Månsson; David Gustafsson; Johan Moverare; Martin Hughes; Linköpings universitet; []
   Nyckelord :;

   Sammanfattning : In this thesis an investigation and modelling of the fatigue crack propagation in the nickel based superalloy Inconel 718, with a special emphasis on the effect of hold times, is presented. The modelling work has been concentrated on describing the hold time fatigue crack propagation by using the concept of a damaged zone in front of the crack tip, which is believed to have a lowered resistance against crack propagation. 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. Deformation and Fatigue Behaviour of Aluminium Alloys for High Specific Power IC Engine Applications

   Författare :Elanghovan Natesan; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cylinder head; aluminium; constitutive models; thermo-mechanical fatigue; fatigue; ageing; mechanical behaviour; A356;

   Sammanfattning : The development towards higher specific power and lower displacement engines in recent years has placed increasingly high thermal loads on the internal combustion engine materials. Further, the advent of hybrid power trains placing higher demands on quick starts and a rapid approach to maximum power necessitates the automotive industry to move towards a more robust computational thermo-mechanical fatigue life prediction methodology to develop reliable engines and reduce developmental costs. LÄS MER

5. 4. Oxygen Induced High Temperature Crack Growth in Ni-base Superalloys

   Författare :Leif Viskari; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Diffusion; Environmental influence; Crack growth; Atom probe tomography; Electron Microscopy; Deformation; Crack tip oxidation; Hold-time fatigue;

   Sammanfattning : Oxygen induced crack growth is a serious concern for the performance of Ni-base superalloys. These alloys are used in gas-turbine engines where they are exposed to hightemperatures, mechanical loads and oxygen-rich environments. LÄS MER

7. 5. Modelling of cyclic and viscous behaviour of thermomechanically loaded pearlitic steels; Application to tread braked railway wheels

   Författare :Ali Esmaeili; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rolling contact fatigue; plasticity; tread braking; full-scale brake rig testing; Railway wheels; finite element analyses; pearlitic steel; viscoplasticity; ratchetting; phase transformations;

   Sammanfattning : In service, railway wheel and rail materials are subjected to high stresses and, in some cases, elevated temperatures. The high stresses are caused by the rolling contact between wheel and rail. Furthermore, heat generated from tread braking and/or sliding between wheel and rail gives additional stress due to constrained thermal expansion. LÄS MER