Prediction of the normal contact stiffness between elastic rough surfaces in lubricated contact via an equivalent thin layer

Abstract

In this work, the normal contact stiffness of lubricated rough interface is evaluated theoretically by describing the lubricated rough interface as an equivalent thin layer. Layer parameters, including equivalent thickness and effective Young’s modulus, are used to characterize the normal contact stiffness by incorporating the contributions of asperity contact and lubricant contact simultaneously. On the basis of layer parameters, the normal contact stiffness of lubricated rough interface is obtained as a function of interfacial separation, surface topography, and properties of contacting solids and lubricants. Effects of surface topographies and lubricant types on the normal contact stiffness are investigated at varying interfacial separations and contact area fractions. The proportion of solid stiffness and lubricant stiffness from the total normal stiffness is also discussed. Numerical solutions reveal that the normal contact stiffness depends sensitively on the lubricant property at initial contact, whereas the influences of surface topographies become obvious with the decrement of interfacial separation or increment of contact area fraction. Comparisons between the predicted values of normal contact stiffness and experimental data for both dry interface and lubricated interface are presented to validate the rationality of the developed model.

An improved acoustic model for mixed lubrication contact interface

“…The acoustic properties of the specimen and lubricants are listed in Table 1. According to the research of Sun et al, 15 the surface topographical parameters under these two lubrication conditions are determined according to statistical laws and are listed in Table 2. Note that the roughness values in Table 2 are measured results after unloading.…”

“…contact pressure and contact stiffness), such as the determination of mechanical parameters (Young's modulus and shear modulus) in the virtual material layer acoustic model. [15][16][17][18] Recently, the virtual material hypothesis-based method has been used to predict the normal contact stiffness between rough surfaces. 15 Xiao and Sun.…”

“…[15][16][17][18] Recently, the virtual material hypothesis-based method has been used to predict the normal contact stiffness between rough surfaces. 15 Xiao and Sun. 16 theoretically evaluated the normal contact stiffness of the lubricated rough interface by describing the lubricated rough interface as an equivalent thin layer.…”

Connection force measurement of precision small interference components using ultrasound

“…As shown in Figure 2, d is the distance between the plane of the mean surface height and the plane of the mean asperities' height. F n (z n ) can be expressed as Sun et al 20 d = 0:25 ffiffi ffi…”

“…This technique relies on the reflection coefficient-contact stiffness relationship given by the acoustic model, such as the quasi-static spring model, 16 statistical contact model, [17][18][19] and virtual material hypothesis-based model. 20 For these models, interface separation is required. The interface contact stiffness is closely related to the topographic characteristics of the rough surface.…”