Global sensitivity analysis of design variables for porous hydrostatic gas bearings considering uncertainty

Porous hydrostatic gas bearing (PHGB) utilizes porous materials as restrictors and is widely recognized in mechanical equipment and scientific instruments due to their exceptional stability and load capacity. At present, the design of PHGB relies on deterministic models to calculate bearing capacity and stiffness, and the adjustment of parameters such as air supply pressure and bearing clearance mainly depends on experience. However, uncertainties related to compressor performance, material properties, and manufacturing errors are inevitably introduced in the practical applications, which can significantly affect the design performance of PHGBs. To address these challenges, this paper presents a global sensitivity analysis to identify the sensitive factors causing variations in the mechanical properties of PHGBs. First, a PHGB model is developed based on the Darcy and continuity equations, and its predictive accuracy for bearing characteristics is validated. Subsequently, a global sensitivity analysis method employing sparse polynomial chaos expansion is introduced to quantitatively assess the impact of uncertainties such as supply pressure, bearing length, diameter, clearance, and eccentricity on load capacity and mass flow rate. This analysis identifies the most critical uncertain parameters influencing the mechanical performance of PHGBs. The insights gained from this study will enable designers to comprehensively understand the mechanical performance of bearings under uncertainty while reducing computational costs, thus providing a valuable theoretical foundation for PHGB analysis and design.