| This dissertation begins from the angle of bionics, Aiming at the characteristic of oil storage lubrication which occurs in the pits of piston surface, Bionic non-smooth effect is applied to the research of the lubrication mechanism about piston-cylinder friction pair, a mathematical model is built up in order to describe large-amplitude sloshing of the lubricating oil with the up-down motion of the piston. Then, this sloshing problem is solved by an ALE (Arbitrary Lagrange-Euler) finite element method. From an example, sloshing free surface and wave height are obtained and the effects of lubricating properties on wave height is analyzed. At the same time, the friction heating's mathematical model of piston-cylinder friction pair is solved with the theory of thermo-mechanical coupling, and some changes of thermo-dynamic performance of the piston skirt are obtained after introducing the pits structure, a principle is provided for the design of the non-smooth oil storage pits. The main research content and achievements are as follows.(1) Biological non-smooth phenomena and bionics application is introduced, the application of bionic non-smooth effect on piston-cylinder friction pair is summarized. Non-smooth effect of earthworm's body surface excreting and storage slime is applied to the research of the lubrication about piston-cylinder friction pair;(2) In the pits, the sloshing wave height of lubricant's free surface will perform large displacement and large deformation, this problem belongs to geometric nonlinear. Building balance equation of the structure must base on the state of deformation, and geometric equations can't also be simplified for the linear form. Therefore, the second chapter of this dissertation describes some theory about the nonlinear finite element. A detailed description about center difference method that often uses in solving nonlinear problems is showed, which paves the way to solve the problems of the follow chapters;(3) By taking the ALE finite element analysis method that often solves the large-amplitude sloshing problems and using center difference method for numerical discretization on time domain, which can deduce corresponding finite element numerical discretization equation with Galerkin weighted residual method. Non-linear finite element solver LS-DNYA is used to simulate numerically this sloshing problem. The free surface shape and wave height of lubricant in three different pits(hemispherical pits,the wedge-shaped pits and conical pits)are obtained, and the time of lubricant sloshing wave height to the inner surface of the cylinder is calculated out ,too. The advantage and disadvantage of lubrication characteristic of the three kinds of pits is obvious from the result. Excessive distortion and winding of the mesh is avoided and the mesh-updating scheme is better;(4) Some mechanical properties of piston skirt surface are bound to changed after changing the surface from a smooth one into a non-smooth one. In the second chapter of this dissertation, the friction heating's mathematical model of piston-cylinder friction pair is built with the theory of thermo-mechanical coupling. Non-linear finite element solver LS-DYNA is used to solve this model. The temperature distribution and surface wear of the smooth piston skirt and non-smooth piston skirt are obtained.In this dissertation, numerical simulation results show that: When the piston skirt is designed to the pits oil storage structure, it not only can explained the oil storage pits lubricating effect of non-smooth pits, but also can improve the wear resistance of the Piston. There is an important project reference value.
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