| Summary: | 碩士 === 國立暨南國際大學 === 土木工程學系 === 103 === The research mainly use the numerical method to analyze the lubrication behaviors, subsurface stress distributions, and friction coefficients of the EHL line contact problems. There are three kinds of models: secant wedge model, rigid journal bearing model, and EHL of line contact model. Besides, the lubricants of three models are Newtonian fluids. The analytical process is that establish Reynolds’ equation, film thickness equation, and force balance equation first, and then use finite difference method to discretize Reynolds’ equation. In secant wedge model and journal bearing model, the research use point-by-point iteration to revise the film pressure, and use bisection method to revise the minimum film thickness. In EHL of line contact model, the research use Newton-Raphson method to revise the film pressure. If there are some convergence difficulties, the research consider progressively incremental load.
The results show that in secant wedge model and journal bearing model, pressure increase with the increasing load, but film thickness is opposite. If the velocity or viscosity increasing, it will only change the film thickness when ignoring the piezo-viscous effect. In EHL of line contact model, the dimensionless pressure in the inlet zone increase at low load, high velocity, or high viscosity, but the dimensionless pressure at the origin decrease. Besides, the pressure spike become more obvious and minimum film thickness become higher at low load, high velocity, or high viscosity. In stress analysis, the values of stress distribution will only change by loads in the secant wedge model and journal model. However, in EHL of line contact model, the position of stress concentration will move toward the surface at low load, high velocity, or high viscosity. The friction coefficients will decrease when increasing the load, but they will increase when increasing the velocity, viscosity, and minimum film thickness.
|
|---|
