PROSPECTS FOR THE CREATION OF NEW FRICTIONAL MATERIALS FOR THE BRAKES OF THE METRO CARRIAGES
Some of the complex decisions of the Government of Republic of Armenia are the development programs of the Yerevan Metro which are an integral part of the strategic programs. Special attention is paid to their implementation. The importance of the metro is constantly growing, especially in the context of problems with the land transport, while in the context of its development, the measures to ensure the safe operation of the rolling stock are of great importance. The use of reliable braking systems and friction pads is one of the most important conditions, especially in conditions where there is a tendency to increase the speed of the rolling stock. Currently, the list of friction composite materials includes hundreds of composites with various properties. The combination of fillers with certain values leads to the creation of new materials, the properties of which differ significantly from those of the starting materials. By changing the composition, quantity and ratio of fillers, the orientation of reinforcing elements, a wide range of materials with specified characteristics and required properties is obtained. In connection with the need to ensure the safety of the environment, the development of theoretical and technological principles, the creation of frictional asbestos-free polymer materials with specified characteristics and required properties is one of the most important scientific and technical problems of modern frictional materials science. The operational characteristics, technical requirements and working conditions of modern brake materials used in metro cars have been studied. Prospects for the creation of new brake friction materials for subway cars are discussed, and a nomogram of the main directions for increasing their performance criteria is proposed. It has been established that the main direction of the development of brake friction materials for subway cars is the creation of such frictional asbestos-free polymer materials that, under the conditions of high speeds, pressures and temperatures, provide relatively high coefficients of friction and wear resistance, have a high heat capacity, low noise amplitude and ensure the safe operation of the surface layer counterbodies.