FUZZY-FMEA APPROACH FOR RISK ANALYSIS OF SWITCH ELEMENTS

Abstract

Switches are key elements of railway infrastructure. Its moving parts change position depending on whether the upcoming running should be done in straight or in diverging. With a larger number of trains, their load increases, which affects the increased wear of parts, as well as the need for more frequent maintenance. In practice, derailments often occur at switch areas, therefore it is so important from the safety aspect. In this paper, the elements of the switch were considered as technical systems that can fail and lead to an incident situation. The approach of risk analysis of technical systems was applied to determine the scenario of switch failure. First, the switch was decomposed into basic elements that were evaluated by experts with linguistic fuzzy estimates depending on the risk factors. For this purpose, the FMEA method was used, which defines the risk factors: the severity of the defect occurrence, the probability of the defect occurrence, and the ease of failure detection. These factors are considered as criteria in the next step of the process of multi-criteria decision-making using the TOPSIS method. The aim of the work is to find out which are the critical elements based on the TOPSIS method and to rank them. The results of the work show that the risk analysis approach can be successfully applied in the detection and ranking of switch elements, as well as in the search for new design solutions in the strategy of their maintenance and construction.