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Ito M.,Vibration Isolating Materials Laboratory | Sakamoto T.,Vibration Isolating Materials Laboratory | Uehara M.,Concrete Materials Laboratory | Tsuruta K.,Concrete Materials Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2011

Flame resistance is an important requirement for products used in railway vehicles. Heretofore, a halogen-based fire retardant has been mainly applied; however, halogen acid is known to generate a gas which is poisonous to human beings in a combustive state. Accordingly, there is growing interest in halogen-free fire retardants. In recent years, the flame resistance of polymeric products has been increased remarkably through application of nanocomposites technology because nanocomposites, even in small quantities of additives improve their properties, of which flame resistance. For this reason studies have been carried out the application of nanocomposites to the floor sheet of railway vehicle.


Sato D.,Vibration Isolating Materials Laboratory | Hansaka M.,Vibration Isolating Materials Laboratory | Mamada S.,Vibration Isolating Materials Laboratory | Taniguchi N.,Steel and Hybrid Structure Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2012

It is generally difficult to install extremely high soundproof walls without drastic reinforcement of the viaduct because the higher the wall, the greater the wind load and moment. A new type of soundproof system was therefore developed. The proposed system comprises a clear soundproof plate and supporting frames. The top of soundproof plate is supported by a rotary axis and all or a part of the other three sides of the plate are fixed by magnetic attractive forces and offers high soundproof performance in ordinary conditions. When the wind load exceeds the safety limit for the viaduct, the plate opens and the appropriate wind load is released. A load test and wind tunnel test were conducted and the wind load reduction mechanism of the developed system was verified.


Hansaka M.,Vibration Isolating Materials Laboratory | Sato D.,Vibration Isolating Materials Laboratory | Mamada S.,Vibration Isolating Materials Laboratory | Taniguchi N.,Railway Technical Research Institute
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2013

In order to install extra-high soundproof plates on existing soundproof walls while avoiding drastic viaduct reinforcement work, a new type of soundproof plate system was developed called SSRW (soundproofing system equipped with a mechanism of reducing wind load). These plates not only provide effective soundproofing they can also deflect wind load exerted on them maintaining the safety of the viaduct in strong wind conditions. Plate movement is controlled by magnetic attractive force, and the magnetic attractive force around the soundproof plates was calculated by magnetic field analysis. Wind tunnel tests were performed using full-scale prototype of the SSRW and measurements were made of its soundproofing performance to verify the reported mechanism and properties.


Sato D.,Vibration Isolating Materials Laboratory | Hanasaka M.,Vibration Isolating Materials Laboratory | Suzuki M.,Vibration Isolating Materials Laboratory | Mamada S.,Vibration Isolating Materials Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2016

Elastic rubber materials such as rail pads are used on railway tracks in order to absorb vibrations and impact forces generated by passing trains. For example, rail pads reduce vibrations transmitted through the rails to structural track components such as rail fasteners and track slabs. The performance of rubber materials changes with temperature. Thus, there is a concern that the vibration reduction performance of elastic track materials may decrease at low temperatures because of the higher resulting stiffness. Field tests were conducted at the same point on a concrete viaduct in summer and winter to evaluate the influence of ambient temperature on the vibration and noise reduction performance of elastic track materials. The results showed that vibrations in some structural components under the rail pad increased at low temperature, which agrees with the track theory of the track vibration.

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