Experimental Research On Particle Flow Lubrication In Plane Contact And Numerical Simulation Of Particle Damage

The properties of particle lubrication is studied based on end-face tribotester in this thesis, and the process of the particle damage is simulated by using the discrete element numerical analysis techniques.First, the structure design of sample for the plane contact tribopair is carried out. The effect of the introduction of particles,particles properties,particle size and powder film on lubrication properties is studied. Comparison between particle lubrication and other lubrication is also performed. The results show that particle can realize the compensation and rehabilitation of lubrication film by entering the tribopair dynamically and show the similar lubrication effect with that of solid lubrication film and self-lubricating material. The structure and size of the particle have an obviously impact on the lubricating effect, and layered structure and large size powder have a better lubrication. At last, the lubrication and failure criterion of powder is established based on experimental data.Secondly, in order to directly observe the particle damage in the lubrication region, a particle damage model based on discrete element method is established and the dynamic the damage process of particle is simulated. The influence of boundary roughness,boundary speed,boundary displacement and pressure and the internal bonding strength of particle on particle is studied. Simulation results show that the particle damage process begins with the formation of a gradually sloping shear band in the middle of the particle. Through discussion of the effect of variations of the boundary conditions and bonding strength on the particle damage, several key factors on the particle damage are identified, and the parameter range of particle damage is determined,the results could provide foundation for forecasts the particle damage and boundary condition for particle lubrication analysis.