Experimental investigation of characteristics of passive safety elements

Abstract

Development of passive safety elements is a key component in the design and manufacture of railway vehicles. Proper functioning of these elements is of great importance and has a direct influence on the safety of passengers, goods and vehicles. Different types of railway vehicles require absorption elements of different geometries and absorption power. Over the last twelve years, new types of absorption elements have been investigated in Serbia. Research has begun on steel tubes and square cross-sections, which absorb energy based on the principles of folding tubes. Research progressed to seamless tubes with circular cross sections on the basis of two methods of energy absorption: expansion and shrinkage of the tube. The best characteristics were obtained using the shrinking method. The most recent research was based on shrinking tubes in combination with folding tubes in parallel operation. This combined method was chosen as the resulting absorber has higher absorption power with smaller dimensions, which is a key consideration given the available and very limited space for the mounting of the absorber behind the buffer. Experimental investigation of the combined absorber through a scale model was conducted on a Zwick Roell HB250 material testing machine at the Faculty of Mechanical Engineering, University of Belgrade. The recorded parameters showed a gradual increase in force values, a decrease in maximal force values at the start of the folding process, and a significant increase in the absorbed energy compared to the shrinking or folding process alone.