The shaft misalignment under mixed lubrication is an important factor affecting the running performance of the bearing, which can occur under heavy load and unsatisfactory assembly. This paper presents a misaligned journal mixed lubrication model coupling for the asperity contact effect, elastic deformation, viscosity–temperature, and viscosity–pressure effect. The finite difference method was employed to calculate the model, and an experimental apparatus designed in this paper was used to test the friction and temperature characteristics of the specimens. The results show that the pressure field, film thickness, and elastic deformation of the bearing conformed to asymmetric distribution along the axial direction under misalignment conditions and there was a notable end side effect. In addition, the frictional force and side leakage flow were evidently enhanced with the increase in the inclination angle in a certain range. The experimental results showed that there was a visible wear phenomenon on the end sides of the bush and shaft. The research results are beneficial for understanding the mixed lubrication mechanism of misaligned journal bearing.

The instability of a floating object is the main factor preventing near-field acoustic levitation (NAFL) from being widely used in the manufacture of micro-electro-mechanical systems. Therefore, investigating the restoring force due to the generation mechanisms of NAFL is necessary to ensure the stable levitation of the floating object. This study presents a theoretical analysis to evaluate the restoring force based on the gas-film-lubrication theory. The gas-film pressure between the reflector and the radiator is expressed in the form of the dimensionless Reynolds equation in a cylindrical coordinate system, which is solved by an eight-point discrete grid method due to the discontinuous gas-film distribution. An experimental rig is constructed to measure the restoring force at various eccentricities, which can be used to support the developed numerical model. The theoretical results show that the restoring force increases with an increment in eccentricity, which agrees with experimental results. Furthermore, theoretical prediction results indicate that the restoring force increases when the amplitude of the radiator and weight of the levitator increases, which indicates higher system stability. The results of the radiator vibration mode on the restoring force show that the restoring force is the largest in the first-order mode.