چكيده لاتين
Nowadays, the use of slab tracks is prioritized over ballasted track layouts for urban transportation networks. One of the reasons for this preference is the lower maintenance and repair costs compared to ballasted track layouts. Although slab track systems offer several advantages, their main drawback is their higher stiffness compared to ballasted tracks. An efficient solution to this issue is the use of elastomeric materials and resilient fastening systems as components of the railway track structure. Studies conducted on the dynamic behavior of slab tracks can be classified into two categories: those focusing on evaluating the elastic behavior of individual fastening components and those assessing the overall elastic behavior of the integrated fastening system. The objective of this thesis is to determine the effectiveness of different fastening systems in regulating the dynamic behavior of ballastless rail tracks. In recent years, significant efforts have been made by both industry and researchers to evaluate properties related to improved elastic performance, such as static stiffness parameters, dynamic stiffness, insertion loss index, and damping factor. However, the impact of different fastening systems and pad materials on these parameters has not been adequately considered. To address this gap, comprehensive experimental measurements were conducted in this study. The experiments were performed on six fastening system prototypes, including the W14 fastening system with polyethylene and dimpled chloroprene rubber rail pads, as well as a four-hole baseplate fastening system with SKL1 spring clips and high-density polyethylene, dimpled chloroprene rubber, polyurethane, and natural rubber baseplate pads. The study then carried out a parametric analysis of the experimental results, evaluating the influence of insertion loss index, static stiffness, dynamic stiffness, and damping factor. The rigid fasteners, labeled as "RF" in this thesis, are those with static stiffness ranging from 30 to 73 kN/mm, while the resilient fasteners, labeled as "RRF," have static stiffness between 11 and 27 kN/mm. The dynamic stiffness of rigid fasteners varies between 38 and 89 kN/mm, whereas that of resilient fasteners falls within the range of 12 to 33 kN/mm. The results indicate that the highest insertion loss index corresponds to the RRF-PU fastening system, which is a four-hole baseplate fastening system with an SKL1 spring clip and a polyurethane pad, achieving a value of 5 dB and reducing slab track vibrations by up to 40%. Additionally, the highest damping factor was observed in the RRF-PU fastening system. The obtained results were also compared with theoretical and numerical models.
