Sökning: "wheel–rail"

Visar resultat 16 - 20 av 26 avhandlingar innehållade ordet wheel–rail.

1. 16. On wear transitions in the wheel-rail contact

   Författare :Sundh Jon; Ulf Olofsson; Staffan Jacobsson; KTH; []
   Nyckelord :Wear transitions; Wheel; Rail; Wear regime; Wear mechanism; Mechanical engineering; Maskinteknik;

   Sammanfattning : Wear transitions in the wheel–rail contact are of increasing interest since the general trend in railway traffic is toward increased velocities and axle loads. Curving increases the risk of flanging, causing the contact to change from an almost pure rolling wheel tread–rail head contact to more of a sliding wheel flange–rail gauge contact on the high rail in curves. LÄS MER

3. 17. Rail Corrugation Growth on Curves

   Författare :Peter Torstensson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; simulation; track and wheelset structural flexibility; small radius curves; short-pitch rail corrugation; dynamic vehicle–track interaction; test rig and field measurements; wear;

   Sammanfattning : Short-pitch rail corrugation that may develop on the low (inner) rail on small radius curves causes increased noise and vibration levels on railway networks worldwide. In lack of a generally applicable treatment, track authorities are forced to run expensive rail grinding programs on a regular basis to manage these problems. LÄS MER

4. 18. Squat defects and rolling contact fatigue clusters - Numerical investigations of rail and wheel deterioration mechanisms

   Författare :Robin Andersson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rail surface irregularities; rolling contact fatigue clusters; dynamic vehicle–track interaction; rolling contact fatigue; studs; squats; fracture mechanics;

   Sammanfattning : Squat defects, a type of localised rolling contact fatigue damage appearing on rail surfaces with rail break as an ultimate consequence, have concerned infrastructure managers for the last couple of decades. In recent years similar types of defects—so-called studs—that are visually resembling squats, have started to appear. LÄS MER

5. 19. Surface defects in rails - Potential influence of operational parameters on squat initiation

   Författare :Robin Andersson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; RCF; squats; dynamic vehicle–track interaction; rail corrugation; Rail surface irregularities;

   Sammanfattning : Despite significant efforts throughout the last decades, the mechanisms behind the formation of squats — a form of rolling contact fatigue (RCF) damage in rails — are not fully understood. Proposed causes of initiation involve, but are not limited to, small initial rail surface irregularities which yield high contact stresses, rail corrugation and varying friction conditions. LÄS MER

7. 20. 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