Design and analysis of biomimetic micro-groove aerostatic bearing inspired by Populus euphratica veins for enhanced load capacity and stiffness

Abstract

Pocketed orifice-restrictor aerostatic bearings (PORABs) are widely used in ultra-precision machining, metrology, and semiconductor manufacturing. However, the pocket limits further improvement in load capacity and stiffness. The complex vortices within the pocket can induce micro-vibration of aerostatic bearings, which is harmful to the positioning accuracy of state-of-the-art equipment. This contradicts the requirements of state-of-the-art equipment for greater load capacity, stiffness, and stability. A novel biomimetic micro-groove aerostatic bearings (MGABs) inspired by Populus euphratica veins is proposed. The design of the micro-groove provides a transmission channel for the high-pressure air near the orifice. Numerical results, while maintaining the same dead volume, indicate that the high-pressure area of the MGABs covers most of the bearing surface compared to the PORABs. Among the MGABs, the dentate fan-shaped bearing (DFS-B) has a more uniform and larger high-pressure area. Theoretical results indicate that the maximum load capacity of DFS-B increased by 139.82 % and maximum stiffness increased by 484.62 % compared to the PORABs while maintaining a relatively lower maximum mass flow rate. Additionally, the flow field characteristics results show that vortices are difficult to form in the DFS-B. The PORABs and MGABs are manufactured using ultra-precision machining and laser technology. Static and dynamic test-beds are constructed to test the bearings. The experimental results validated the effectiveness of the solution model and demonstrated that the MGABs are superior to PORABs in load capacity, stiffness, and stability.