Study On Thermal-damage Behavior Of Friction Lining Under High-speed Sliding Friction Conditions

Multi-rope friction hoist is one of the key equipments used in mine’s hoisting. The key to ensure its safe and reliable operation lies on the sufficient friction between wire rope and friction lining and the good wear-resistance ability of friction lining. However, due to that the pair of wire rope and friction lining operate in a severe environment and poor working conditions, and continually operate for a very long time, there are often hoist slip accidents, causing great economic losses and casualties.Funded by the National Natural Science Foundation of China(No.: 51105361), study on friction lining’s thermal-damage behavior under high-speed sliding friction conditions was carried out, committed to provide theoretical basis and technical support to decrease severe slip accidents of friction hoist and guidance on mine safety in production and development of new friction lining materials.Aimed at studying the problem of friction hoist’s severe slip accidents, this paper designed a non-joint wire rope and friction lining high-speed sliding friction test system which can simulate friction hoist’s severe slip working conditions, and used the method of combination of theoretical modeling and experimental study to master the temperature field and variation, tribological performance and thermal-damage behavior of friction lining under hoist’s severe slip conditions. The main content includes the following aspects:Firstly, experimental researches on the rheological behavior, the film-forming and tribological properties of the friction-promotion grease(FPG) under point-contact conditions and the application of FPG to the wire rope-friction lining pair were carried out, providing the basis for the analysis on lining’s tribological properties and thermal-damage behavior under grease-lubrication high-speed sliding conditions; through the LFA, DMA, TGA and DSC tests on the friction lining material, GDM326, we obtained its thermophysical and thermomechanical properties, which can provide the basic data for the subsequent work, numerical simulation of friction lining’s temperature field.Secondly, the spiral contact characteristic of friction lining and wire rope was analyzed to obtain the gap(in the discrete form) between the non-deformed multi-point contact surfaces of wire rope and friction lining at an arbitrary time point; On this basis, a friction surface’s contact pressure distribution model was established; based on the implementation that the surface pressure distribution is converted to heat sources in the form of heat flow density, a temperature field model of multi-moving heat sources was then built; subsequently, the multi-grid method was adopted to solve the pressure distribution and the temperature field of friction lining in turn and then turn to the next discrete time point; next is to conduct comparative analysis on the results of different solving schemes of temperature field as well as to study the temperature distribution and its influencing factors.Finally, by conducting tests of high-speed sliding friction between wire rope and friction lining, the friction and wear properties of GDM326 under dry-friction and grease-lubrication conditions were studied; by comparing the results of measured temperature rise and the corresponding simulation results, the theoretical model of lining’s temperature field was validated, and then the multi-grid method solution technique was used to obtain the temperature distribution of the friction surface under each test condition; then, by analyzing the macroscopic and microscopic damage morphologies of the lining’s friction surface after each high-speed sliding friction test, thermal-damage behavior and mechanism of friction lining under dry-friction and grease-lubrication conditions were investigated.