Розрахунок контактного тиску та зони контакту в парах ковзання судових дизелів

Abstract

Annotation – The durability of marine diesels significantly depends on the operation of friction pairs, such as: piston rings - cylinder liner; crankshaft - bearing shell, plunger - sleeve, and others. This is primarily due to the constant contact interaction of the elements of the friction pairs at different temperatures and load. Therefore, the research of normal pressure and the definition of contact areas in the friction pairs, the studying of the influence of the quality of lubricants on these characteristics are important tasks for predicting the longevity of marine diesels. The solution of these problems is based on the application of mathematical models of processes (numerical simulations) that occur in friction pairs. This considers two main processes that occur during the operation of the friction pairs: the research of contact and tangential stresses that occur in friction pairs in the framework of elastic or elastic-plastic contact models; study of hydrodynamic processes in a thin layer of oil between the elements of the friction pairs. The combination of these processes allows to sufficiently assess the influence of the elastic-mechanical properties of the sliding vapor elements and the viscosity and hydrodynamic characteristics of the oils on the durability of the marine diesel unit. The first process is researched in this work. In particular, for the analysis of contact stresses and contact zones in friction pairs, the method of numerical modeling is used, which is based on the differential equations of the theory of elasticity. With the help of fundamental solutions (influence functions), the problem is reduced to an integra-differential equation with the Gilbert’s kernel. The solution of which is constructed using the method of orthogonal polynomials as well as easy-to-use approximation formulas. Numerical simulations were performed, as a result, the maximum pressure and contact zone parameters for some combinations of friction pairs materials of marine diesel engines were determined. In particular, the influence of the radial gap on the pressure distribution and the size of the contact zone between the elements of the friction pairs of marine diesels is established.