Sökning: "growth irregularities"
Visar resultat 1 - 5 av 12 avhandlingar innehållade orden growth irregularities.
1. Rail Corrugation Growth on Curves
Sammanfattning : The development of periodic irregularities with distinct wavelengths (corrugation) on the low rail of small radius curves is studied through mathematical modelling, numerical simulations, field measurements and laboratory investigations. One year of monitoring of roughness on the low rail of a 120 m radius curve on the metro of Stockholm Public Transport (SL) showed severe growth of rail corrugation with wavelengths of about 5 cm and 8 cm. LÄS MER
2. On Peritectic Reactions and Transformations and Hot Forming of Cast Structures
Sammanfattning : This thesis deals with peritectic reactions and transformations that occur during the solidification of many alloys. Peritectics are believed to be a major cause of crack-formation in many steels, thus, good knowledge of the mechanisms by which these phenomena occur is essential for preventing such defects. LÄS MER
3. Dynamic Train/Track Interaction: Simulation of Railhead Corrugation Growth under a Moving Bogie Using Mathematical Models Combined with Full-Scale Measurements
Sammanfattning : Heavier trains and higher speeds have increased the need for high-quality tracks and vehicles in order to fulfill safety and environmental requests. The phenomena involved in dynamic train/track interaction lead to noise radiation, induce ground-borne vibrations and degrade the track structure and the railcar wheels. LÄS MER
4. Growth of fatigue cracks subjected to non-proportional Mode I and II
Sammanfattning : This thesis deals with some aspects of crack growth in the presence of cyclic loading, i.e. fatigue. The cyclic load cases studied here are primary of non-proportional mixed mode type. LÄS MER
5. Strain-assisted corrosion cracking and growth rate inhibitors
Sammanfattning : A model for evolution of cracks as a result of strain-assisted corrosion is presented. The considered cracks possess a realistic geometry, where the tip region is an integral part of the crack surface instead of being a singular point. This geometry is either implicitly defined or is a consequence of crack nucleation from surface irregularities. LÄS MER