Application of SMA Composites in the Collectors of the Railway Pantograph for the Italian High Speed Train

Shape memory alloy attract increasing interest as materials that can be used for passive as well as active damping applications. Many theoretical and experimental study on intelligent and/or smart materials and structures have been performed for more than a decade now. In this paper an application of SMA material to improve the dynamic performance of the collector of the pantograph for the Italian high speed train is investigated. The effect of collector deformability on the contact force exchanged between pantograph and catenary is of interest because when considering current collection at high speed, the dynamic interaction between the collectors and the contact wire is an aspect in which the collector deformable modes can play an important role. In a previous work it has been established that to increase the modal damping of the flexural mode of the collectors is fundamental to increase the specific damping of the lateral horns. At now, the material of the lateral horns is Glass Fiber Reinforced Polymer. Ti-Ni alloy yarns can be used as "smart fibers" embedded in this conventional material so as to make new horns with increased damping capacity. The work consists in: - the set up of the fabrication process of the horns in which two layers of SMA long fibers are embedded close to its top and the bottom surface (far from the flexural neutral axis); - dynamic tests aimed at identifying natural frequencies, damping ratio, and mode shapes of the new designed horn has been undertaken; - FE model of the SMA composites horn has validate, comparing the results dynamic numerical analysis with the results of the experimental, and used to optimize the number and the diameter of the embedded yarns; - FE model of the collector with the new horns has been set up and used to investigate numerally its dynamic behaviour.