Thermo-stress Coupling Behavior Of Lining During Sliding In Friction Hoist

A friction hoist is the one of the most important equipments in mine, and the special friction pair between friction lining and wire rope in friction hoist is the key to guaranteeing its safe and reliable operation. This dissertation was financially supported by Research Fund for the Doctoral Program of Higher Education of China. Aiming at the problem of sliding friction between friction lining and wire rope, the thermo-stress coupling behavior of friction lining is investigated to seek the intrinsic mechanism and variation of the friction contact properties with different operating condition, which will be beneficial to avoid the accident of overwinding and overfalling, develop new friction lining and consequently guarantee the safe and reliable operation of friction hoist.The main content of this study includes: the friction lining's temperature field under the condition of non-complete contact, the friction contact between friction lining and wire rope with low-speed sliding and the thermo-stress coupling behavior. And the thermo-stress during the sliding process was simulated by the software of finite element analysis. Consequently, the temperature field, stress field as well as thermo-stress coupling behavior were studied. Furthermore, the sliding friction experiment between friction lining and wire rope was carried out on the friction tester to verify the theoretical model.Firstly, the dynamic thermophysical properties were obtained by the thermal analysis and the dynamic distribution coefficient of heat-flow was analyzed theoretically. And the helical contact property was analyzed by considering the strand's helical structure. Moreover, the model of friction lining's temperature field was set up under the condition of non-complete contact with wire rope, and the finite difference method was applied to solve this problem. Subsequently, the friction experiment was performed on the friction tester and the theoretical model was verified by comparison between the simulation results and the expermental results.Secondly, the variation of mechanical properties with loading time and frequency was gained by the mechanical experiment of multi-frequency time spectrum. Through combination of the theory of viscoelasticity and contact mechanics with friction, the contact mechanics with friction between friction lining and wire rope was established and solved theoretically. Furthermore, the sliding friction experiment was carried out on the friction tester, and the experimental results show that the theoretical model is correct. Finally, the dynamic mechanical properties of frictin ling were investigated by DMA and the variation of complex modulus with temperature and frequency was obtained. Besides, the thermoviscoelastic constitutive relation of friction lining was established by regression analysis. Taking into account the temperauture field with non-complete contact, stress field with sliding friction contact and thermoviscoelastic constitutive relation, the thermo-stress coupling model was established. Moreover, the numerical simulation was performed by multiphysics coupling software of finite element analysis. In the end, the temperature and strain at testing points were measured simultaneously, and the simulation results were compared with experimental results to verify the theoretical model of thermo-stress.