Triennial Report 2003 - CHARMEC

Materials and maintenance – Material och underhåll (MU) – Werkstoff und Unterhalt – Matériaux et entretienMU10. CRACK PROPAGATION IN RAILWAY WHEELSSprickfortplantning i järnvägshjulRissausbreitung in EisenbahnrädernPropagation de fissures dans les roues ferroviairesProject leadersand supervisorsProfessor Hans Andersson,Dr Elena Kabo andDr Anders Ekberg,Applied MechanicsDoctoral candidate Ms Eka Lansler, MSc(from 2002-02-01)Period 2002-02-01 – 2003-06-30(– 2007-01-31)Chalmers budget Stage 3: ksek 1100(excluding university Stage 4: ksek 2050basic resources)Industrial interests Stage 3: ksek 400in-kind budget Stage 4: ksek 200(Lucchini Sweden)PhD student Eka Lansler (left) and her supervisors ProfessorHans Andersson (right), Dr Elena Kabo and Dr Anders Ekbergin project MU10Cracks in dynamically loaded metal structures are usuallyunavoidable. One design philosophy then is to ensurethat the structure is inspected for cracks before any ofthem has reached a critical size. This requires predictivemodels of how rapidly a crack grows in the structure andunder what conditions it will lead to complete structuralfailure. The aim of the mu10 project is to establish suitablemodels of crack growth and fracture for railwaywheels. In particular, cracks initiated below the treadsurface are to be studied keeping in mind that suchcracks grow in a multiaxial and essentially compressivestress field with rotating principal directions. A projectplan dated 2001-02-08 was approved by the charmecBoard on 20 February 2001.Eka Lansler has attended graduate courses in preparationfor her research work. A finite element modelof a deep crack in a railway wheel has been developed.Numerical studies have been made of the relative displacementof the two faces of a subsurface crack duringa load passage. A qualitative understanding has beenobtained on how these displacements are influenced byparameters such as contact load magnitude and contactgeometry. Methods for crack growth prediction based onmechanical quantities (stresses, strains, stress intensities,J-integrals etc) and measures of material resistance arecurrently being investigated.The reference group of the project mu10 has membersfrom Bombardier Transportation, Duroc Rail and Train-Tech Engineering.Eka Lansler and Elena Kabo: Sub-surface crack face displacementsin railway wheels, Proceedings 6th InternationalConference on Contact Mechanics and Wear of Rail/WheelSystems (CM2003), Gothenburg June 2003, vol II, pp 369-375→ (FROM PREVIOUS PAGE)Anders Ekberg, Elena Kabo and Hans Andersson: An engineeringmodel for prediction of rolling contact fatigue ofrailway wheels, Fatigue & Fracture of Engineering Materials& Structures, vol 25, no 10, 2002, pp 899-909Anders Ekberg and Elena Kabo: Rolling contact fatigue ofrailway wheels and rails – an overview, Proceedings RollingContact Fatigue: Applications and Development, Brescia (Italy)November 2002, pp 5-26Elena Kabo and Anders Ekberg: The influence of defectsin rolling contact fatigue, ibidem, pp 85-93Elena Kabo and Anders Ekberg: Material defects in rollingcontact fatigue of railway wheels – the influence of defect size,Proceedings 6th International Conference on Contact Mechanicsand Wear of Rail/Wheel Systems (CM2003), Gothenburg June2003, vol I, pp 119-125Anders Ekberg and Elena Kabo: Rolling contact fatigue ofrailway wheels and rails – an overview, ibidem, Appendix II,pp 11-24Anders Ekberg, Elena Kabo and Jens Nielsen: Integratingrolling contact fatigue analysis with simulation of dynamictrain-track interaction, Proceedings 3rd International Conference“XXI Century Rolling Stock (ideas, requirements,projects)”, St Petersburg (Russia) July 2003, 11 pp40