The load-carrying capacity and friction coefficient of incompressible textured parallel slider bearings with surface roughness inside the texture features

Surface texturing is used to increase hydrodynamic pressure and reduce friction and wear between parallel sliding surfaces in a variety of applications. The shape, geometry, and density of the patterned microtexture features play a key role in the tribological performance of such textured slider bearings. Lubrication models are used to predict the load-carrying capacity, friction coefficient, and volume flow rate of textured bearings, assuming a smooth surface and ideal shape of the texture features. However, experimental evidence shows that manufacturing techniques such as laser surface texturing only approach the ideal shape of the texture features. Moreover, the manufacturing process typically creates roughness inside the texture features. In this paper, we numerically evaluate the effect of roughness inside the texture features on the load-carrying capacity, friction coefficient, and volume flow rate of the textured parallel slider bearing. We consider the cases of sinusoidal roughness and isotropic random roughness with Gaussian distribution of surface heights and find that the effect of roughness inside the texture features on the bearing load-carrying capacity and friction coefficient increases with increasing roughness height and increasing wavelength of the roughness. In addition, the effect of sinusoidal roughness is larger than the effect of isotropic random roughness with Gaussian distribution of surface heights. We also find that the roughness inside the texture features has negligible impact on the volume flow rate of the textured bearing.