Improving of absorption power of tube collision energy absorber by using polyurethane foam

Abstract

Tendencies to increase the speed in the railway transport lead to intensive work on active and passive safety improvement of railway vehicles with the aim to reduce possibilities of collision to a minimum. Frequently, we have collisions in the main railway stations during shunting and forming trains at speed higher than allowed. Consequences of these collisions are damages of the vehicles structure and sometimes parts of infrastructure that require time for repairs. These reduce the availability of the vehicles and causes loss of profit and increase of maintenance costs. Subject of this paper is experimental investigation of absorption characteristics of foam filled tube collision energy absorber which works on the principle of shrinking the seamless tube through special cone bushing. This type of absorber is intended for mounting in a line with standard buffer. Tube is filled with high density polyurethane foam with the aim to increase deformation resistance during collision. Using shrinking process energy absorption occurs by elastic-plastic deformations of the tube, friction between the tube and the cone bushing and compression resistance of high density polyurethane foam. This type of absorber gives gradually increase of the deformation resistance and higher absorption power in comparison with empty seamless tube. Experimental researches were realized on the hydraulic testing machine in the laboratory conditions. During tests, reaction force on defined stroke was measured. Results of the experimental investigations of foam filled tube collision energy absorber and empty tube collision energy absorbers were compared.