stage 6 triennial report 1 July 2009–30 June 2012 ... - CHARMEC

Materials and maintenance – Material och underhåll (MU) – Werkstoff und Unterhalt – Matériaux et entretien
MU8. BUTT-WELDING OF RAILS
Stumsvetsning av räl
Stumpfschweissen von Schienen
Soudure bout à bout de rails
The mu8 project was completed with Anders Skyttebol’s
successful defence in public of his doctoral dissertation in
September 2004, when he also left Chalmers. The facultyappointed
external examiner of the dissertation was
Professor Fredrick V Lawrence Jr from the Department of
Civil and Environmental Engineering at the University of
Illinois in Urbana-Champaign, usa. Professor Lennart
Josefson together with Docent (now Professor) Jonas
Ringsberg, both of Chalmers Applied Mechanics, supervised
Anders Skyttebol’s research. The title of the dissertation
is “Continuous welded railway rails – residual stress
analyses, fatigue assessments and experiments”.
A detailed three-dimensional numerical simulation of
the electrical, thermal and mechanical fields during flash
butt-welding was performed in project mu8. Data for the
thermal and electrical analyses were obtained both from
the manufacturer of welding equipment and from Banverket’s
(now Trafikverket) shop at Sannahed. The constitutive
model that was developed handles the recovery of
hardening for a material that solidifies after being melted.
Materials and maintenance – Material och underhåll (MU) – Werkstoff und Unterhalt – Matériaux et entretien
Rullkontaktutmattning av järnvägshjul
Ermüdung von Eisenbahnrädern durch Rollkontakt
Fatigue des roues ferroviaires due au contact roulant
Docent Anders Ekberg and Dr (now Docent) Elena Kabo
(for photo, see page 61) led this senior research project,
concluded in June 2006, with Professor Roger Lundén as
their co-worker. The overall aim of project mu9 was to
develop an “engineering” approach to rolling contact
fatigue analysis while accounting for load magnitude,
material quality, material anisotropy, material defects and
manufacturing processes and also plastic deformations in
operation. Several meetings were held with Bombardier
Transportation, Deutsche Bahn, Duroc Rail, Lucchini
Sweden, mtab, Spoornet, Interfleet Technology and others
for project discussions.
Verifying experiments were carried out at Sannahed. The
redistribution of welding residual stresses and the growth
of fatigue cracks from defects in the rail weld was simulated.
The time period for the growth of cracks from a size
detectable by ultrasonics to a critical size was estimated.
See also charmec’s Triennial Reports for Stages 3 and 4.
PhD student Anders Skyttebol (left; doctorate earned in September
2004) and his supervisor Professor Lennart Josefson in project MU8.
Photo taken in 2003. For a more recent photo of Lennart Josefson,
see page 52. For a photo of Jonas Ringsberg, see page 41
MU9. ROLLING CONTACT FATIGUE OF RAILWAY WhEELS
The computer program fierce (Fatigue Index Evaluator
for Rolling Contact Environments) was developed and released
as a stand-alone matlab code and has also been incorporated
into commercial dynamic codes such as adams/
Rail and gensys. The fierce code evaluates the fatigue
impact on the wheel rim based on the output from simulations
of dynamic train–track interaction. Updated versions
of fierce are being provided to Bombardier Transportation
and other industrial partners. See also charmec’s
Triennial Reports for Stages 3 and 4. The joint reference
group for projects mu9 and mu10 included representatives
from Bombardier Transportation Sweden and Interfleet
Technology.
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