Damping of dynamic forces by materials used in the construction of ballast and ballastless tracks. Polymer pads

• Published in: Vestnik naučno-issledovatelʹskogo instituta železnodorožnogo transporta (Online) Vol. 77; no. 5; pp. 310 - 320
• Main Author: V. M. Bel’kov
• Format: Journal Article
• Language: English
• Published: Joint Stock Company «Railway Scientific and Research Institute 13-11-2018
• Subjects: comparative analysis; damping; elastic-viscoplastic properties of materials; layered polymeric materials; vertical vibration waves
• ISSN: 2223-9731; 2713-2560
• DOI: 10.21780/2223-9731-2018-77-5-310-320

The article provides calculations of coefficients of polymer damping pads with elaborated materials that ensure minimal impact on soils under railway trackside and exclude its subsidence in a wide operating range of temperatures and frequencies. Application of additional metal plate between the pad under the rails and the pad on a sleeper was substantiated based on the theory of wave processes, that allows reducing amplitude of vibrational waves in rail and wheel by six times due to reflection in reversed phase at the “rail metal — polymer” border, and reduces the amplitude of the wave by three times due to reflection of vibrational waves in the “metal plate — pad — concrete sleeper” segment. Considering Russian extreme continental climate thermoplastic elastomers are recommended to use as under-rail pads, and polyurethanes for sleepers. An aluminum plate should be installed to increase damping factor between lining and pads. Such a composite lining can be operated at extremely low temperatures from –60 °С, and high to +80 °С. Significant amount of rubber and polyurethane pads is produced worldwide for different climatic and operating conditions. After conducting accelerated tests author suggests a transition to two or three types of “thermoplastic elastomer — metal — polyurethane” composite pads in order to unify a variety of different types of polymer pads according to the operating conditions, the material and construction used.