Experimental research of characteristics of improved type of combined tube energy absorber

Abstract

Crash energy absorber represents one of the main and necessary elements of body structure of modern railway vehicles. Intensive research in the field of passive safety produced more different types of collision energy absorbers using different shapes of deformations to absorb as much kinetic collision energy as possible. Different combinations of the shape of deformations lead to compact dimensions of absorber. Subject of this paper is combined energy absorber which works on the principle of shrinking and splitting the seamless tube at the same time, using pecial tools. Using shrinking-splitting process energy absorption occurs by elastic-plastic deformations of the tube and friction between the tube and the cone bush, respectively friction between the tube and the splitting tool. Energy absorption starts in the tube which is compressed into cone bush. After exactly defined stroke in the process of energy absorption by shrinking the seamless tube, the simultaneous process of splitting of the tube starts, so tube deforms in parallel shrinking-splitting mode during the rest of the stroke. This type of combined process gives gradually increase of the force without undesirable peaks which characterizes second phase of deformation of shrinkingfolding combined absorber. Experimental research was realized via quasi-static tests in the laboratory conditions. During tests, reaction force and stroke were measured. Results of the investigations of combined shrinking-splitting absorber and shrinking-folding absorber were compared.