A new approach for adaptive ultra-precision air bearing for enhanced loading support

This research investigates the dynamic characteristics and stability of adaptive ultra-precision air bearings (UABs) incorporating partial porous orifice (PPO) structures for enhanced loading support. The study focuses on the influence of structural components, such as the rotor, shell and platform on UAB performance across a broad frequency range from 10 − 2 to 10 6 Hz. A modified dynamic grid model was also developed using fluent software to simulate the effects of PPO throttling parameters such as the number, size and height of orifices on the pressure distribution within semicircular models of partially multiple porous orifices with a core pressure unit (CPU). Experimental investigations monitored acceleration and displacement under a constant frequency of 624.29 Hz, revealing a maximum acceleration of 0.5 m / s 2 for shell and 0.05 m / s 2 for the isolation platform, with minimal displacements (0.05µm for the shell, below 0.02µm for the platform). Furthermore, the dynamic stiffness and damping were observed across various operational parameters such as air film thickness (h), inlet pressure ( p ) and permeability (k). The results show indicate that the dynamic capacity amplitude decreases with increasing frequency while damping parameters are reduced as the number of orifices increases. Conversely, a larger orifice diameter improves damping characteristics at constant perturbation frequencies. Notably, increasing the orifice height significantly reduces damping, particularly at low frequencies. This study provides key insight into the design and operational parameters influencing the efficiency and reliability of adaptive air bearings offering pathways for further advancements in high-precision applications.