Nonlinear dynamic model of elastohydrodynamic lubricated line contact

Despite their typical design, the lubricated slideways of machine tools are among the most complex systems in engineering science. Given the dynamic interaction of interfaces, along with vertical and horizontal oscillations, in these sliding lubricated line contacts, it is necessary to investigate their dynamic friction and normal dynamic behavior with coupling effects between them. This paper presents a new method to model the nonlinear normal behavior of sliding lubricated line contacts and have a precise and complete description of the nonlinear dynamic behavior of such components in a mixed lubrication regime without using the complicated theories in a systematic procedure. The nonlinear normal model was developed according to Taylor series expansion of oil film and asperity forces. The model was completely consistent with the transient form of elastohydrodynamic and asperity contact differential equations (the original model). By using the least mean square technique, the Taylor series coefficients of the nonlinear model in the time domain were identified. In order to select the terms that had dominant effects on the nonlinear oil film forces, the subset selection method was used. The results were so close to the predicted responses based on the original and identified nonlinear model.