Detection, investigation and modeling of road defects in rail systems according to vibration data

Critical increases in the use of rail transport are taking place in line with the growing global population and human needs. Due to increased usage, increased loads and speeds on trains also pose safety risks. In this thesis, modeling and prototype analyses were carried out to identify safety problems that may occur in rail transport and to realize estimates of maintenance period. Displacement, acceleration and stress values were examined in line with the vibration effects of rail transportation vehicles on the ground depending on their own weight. The development of defects, their geometry and defect locations are detected in the time domain. A prototype design has been developed at small scales. Simulative and experimental analyzes of the design were carried out. Imperfect road conditions such as under-road gap and protrusion type were compared with perfect road conditions. The gap defect under the traverse had a surface area of 4425 square millimeter. Dimensions of the protrusion on the road were 1.5 millimeter (height) and a 25 millimeter (length). Displacement variation for the under-road gap were determined as 61.8%. The change in acceleration values was 108.7%. In experimental studies, acceleration increases were concentrated in the regions where the defect was located and the average change was 12.5%. When the defect (protrusion) created on the road was examined, a 2.9% change was observed in the displacement data. In terms of simulative and experimental measurement of acceleration data, the increases were determined as 4.71% and 3.56%, respectively. Simulative studies at real road scales were analyzed in the range of 20-100 Hz. and 50-500 kN load values. Responses for defects of different geometries and sizes were investigated, and it was observed that detectability increased at frequency values of 40, 60, 80 Hz, and the numerical results were found to be consistent with small-scale prototype applications. Responses based on vibration effects were analyzed and positive results were obtained. Simulative analyses were supported by experimental studies and their compatibility was presented with detailed graphics in the results subsection.