Abstract
Abstract
Based on a mechanistic model of entrapment and rejection of spherical debris particles in elliptical contacts of various machine elements, which has been recently published by the present author, a parametric study has been conducted to analyse the effects of the contact load and speed, lubricant viscosity (in the case of lubricated contacts) and particle-contact-counterface friction coefficients on the critical particle size for entrapment, rejection, and intermediate states. The simulation involved a conforming as well as a non-conforming elliptical contact. The parameters were varied in unequal steps as follows: contact load from 5 to 500 N, contact speed (average speed of the two counterfaces) from 0.005 to 5.500 m/s, the lubricant dynamic viscosity from 0.001 to 1.000 Pa s, and the friction coefficient between a particle and a contact counterface from 0.02 to 0.20 (with, generally, different coefficients used for the two counterfaces). The results are in the form of two- and three-dimensional graphs and contour maps, showing the zones of particle entrapment, rejection, ‘weak rejection’, etc. in the contact inlet; the critical particle sizes for entrapment and rejection; as well as graphs showing most of these parameters and effects together for quick assessment. The model has proved to be an efficient mathematical tool in predicting the risks of contact damage due to debris particles by offering both clear quantitative as well as qualitative answers, and can assist in the selection of proper filtration or sealing systems, or simply be used as a supplementary tool in life-expectancy calculations of concentrated contacts in machine-element applications.
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