Study On The Fast Direct Iterative Algorithm For Heavy Loaded Point Contact EHL And The Pressure Spike Under The Point Contact EHL State

This dissertation is composed of two parts. They are the study on the fast algorithm for heavy loaded point contact EHL and the pressure spike under the point contact EHL state.In part one, the author gives detailed theory analysis and numerical study to the fast algorithm for heavy loaded point contact EHL.The improved composite direct iterative method with three layers cycle iterative format is proposed by the author on the basis of the fast direct iterative method for point contact EHL in this part, we use this method to solve the point contact isothermal elastohydrodynamic lubrication problem under light load, medium load and heavy load condition, the improved algorithm has better convergence accuracy and a wider range of load, which is verified by the a large number of numerical examples. The influence to film thickness calculation precision of half band width β’selection is investigated in this thesis; the change of half band width β has a certain effect on minimum film thickness, while the influence to center film thickness is little.In the part two, the author introduces the least squares data fitting method for the research for pressure spike in the point contact EHL state, choosing appropriate fitting curve according to the change relations between pressure spike amplitude, parameter of velocity and load parameter. Based on the analysis of a large numerical examples, pressure spike amplitude equation and hertz center pressure formula of heavy loaded point contact elastohydrodynamic lubrication are fitted out by the least squares data fitting method. We use two formulas to solve new numerical example, including light load, medium load and heavy load numerical example, and analysis calculation accuracy and loading range of the two formulas, calculation show that the relative error between calculated value of two fitting formulas and calculated value of improved algorithm in this thesis control within±10%, which has verified accuracy and feasibility of the two fitting formula.