Friction and wear on-line monitoring and wear mechanism analysis under dynamic loading manners

The experiments of ball-on-disc were conducted to investigate the friction and wear process under the chosen the loading modes of stepped, transient-high and damped harmonic excitation (DHE) loadings. Force sensor and on-line visual Ferrograph (OLVF) sensor were used to monitor the friction and wear process in-situ, respectively, and the morphology of wear track was analyzed. Comparing with constant loading, it can be seen that the stepped loading can decrease the peak value of wear rate during running-in period compared with constant loading. And under transient-high loading, the results of index of particle coverage area (I_IPCA) and coefficient of friction (μ) show that the friction pairs have specific bearing capability, however, wear increases markedly with the duration beyond 60 s. DHE loading is able to cause the μ sharply increasing. Morphology of wear track shows that plastic deformation of surface material is the main wear mode under the constant loading and stepped loading with overloading value, and surface fatigue presents on the wear track under DHE loading. Therefore, friction pair can undergo the specific transient-high loads, stepped loading can improve the tribology performance, and the DHE loading manner is apt to accelerate wear process of friction pair.