Investigations of Dynamic and Thermo-mechanical Wheel-Rail Contact Effects on the Rail
| dc.contributor.advisor | Habtamu, Tkubet (Mr.) | |
| dc.contributor.author | Getu, Ejeta | |
| dc.date.accessioned | 2021-10-19T04:23:03Z | |
| dc.date.accessioned | 2023-11-04T15:17:22Z | |
| dc.date.available | 2021-10-19T04:23:03Z | |
| dc.date.available | 2023-11-04T15:17:22Z | |
| dc.date.issued | 2015-03 | |
| dc.description.abstract | The purpose of the study is to investigate the dynamic and thermo mechanical effects of the rail due to the wheel-rail contact. The guidance of railway vehicles are done by the rails with the carrying wheel loads coming from the axles. But, different loads coming to it may cause damages, especially the heads at the joints and the webs. The friction and thermal power pen-etrant at the continuous rail surfaces, the cracking of the head ends, deformation of fish plate, high impact force, the contact probe energy generation and vibrations due to discrete contact area and rail heads dip down to a joint even on both sides are some of the problems. Therefore, this study focused on two loading effects on the rail. The first is the investigation of dynamic effects and the second is thermo-mechanical effects of the contacts between vehi-cles and rail track during braking. In dynamic analysis, the modal and mechanical transient effects are investigated. Since, a modal analysis is performed on a pre-stressed structure; the static loading effect was first validated. The results for the first five mode shapes of natural frequencies and maximum deformations are: (42.136, 212.22, 259.08, 371.5, 617.67) Hz and (1.1506e-002, 1.1544e-002, 1.1039e-002, 6.3931e-002, 5.0965e-002)m respectively for the continuous rail, and (80.326, 263.43, 335.32, 513.47, 774.65)Hz and (1.116e-002, 1.089e-002, 1.194e-002, 5.4382e-002, 4.8243e-002)m for the jointed rail respectively. In the transi-ent, the total deformations are: 1.4297e-005m & 1.4577e-005m and the Von-mises stresses are: 14.923 Mpa & 20.739 Mpa for the continuous and the jointed rail respectively. Also, the transient total velocity, total acceleration, the joint probe impact forces and the energy probe (for both kinetic and potential) are investigated. Thus, the maximum deformation and von-mises stress of the rail at the joint for the transient is larger than at continuum part. In thermo-mechanical analysis, the transient thermal effects on the rail, in addition to the stat-ic mechanical loads were explored. In this case, the rail body temperature that is generated during braking was imported to the mechanical loading and the combined effects were ex-plained. The thermo-mechanical braking effects developed on the three rail track level condi-tions: during the downgrade braking, at the straight track braking and at the curved track braking. The maximum temperature rises for the three cases ( ) are: 49.373, 42.576, 378.77 and the thermo-mechanical von mises stresses ( Mpa) are:57.42,43.42 and 41.87. As shown in results, the combined thermal and mechanical effects are the highest at the downhill brak-ing. | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/123456789/28215 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Rail | en_US |
| dc.subject | dynamic | en_US |
| dc.subject | mode shape | en_US |
| dc.subject | thermo-mechanical | en_US |
| dc.title | Investigations of Dynamic and Thermo-mechanical Wheel-Rail Contact Effects on the Rail | en_US |
| dc.type | Thesis | en_US |