Development and Validation of a Standardized Evaluation Procedure for Marine Application of Magnetic Bearing-Based Rotating Machinery

Abstract

Unlike conventional bearings, magnetic bearings (MBs) provide non-contact support and high reliability, but standardized evaluation criteria for marine environments have not yet been established. This study proposes and validates a standardized evaluation procedure for MB-based rotating machinery intended for marine applications. The proposed procedure consists of six steps: (1) equipment data preparation, (2) standardized simplified model generation, (3) magnetic force incorporation, (4) external load definition based on the sea state, (5) analysis (transient dynamic analysis under the defined external loads), and (6) result evaluation. A simplified turbo compressor model was constructed using ANSYS Mechanical, applying equivalent stiffness and damping coefficients to represent magnetic bearing dynamics. External loads were derived from World Meteorological Organization (WMO) Sea State and DNV-RP-C205 guidelines and applied as impulse-type accelerations. Numerical simulation results showed that rotor displacement remained within 95% of the air gap under normal conditions (Sea state 6, 0.8g, here, g = 9.8 m/s<sup>2</sup>). Under extreme loading (Sea state 8, 1.8g), the analysis indicated that the air-gap limit was exceeded, leading to contact with the backup bearings and casing. The proposed standardized simplified evaluation procedure provides a practical framework for assessing MB-based marine rotating machinery, supporting rapid design verification and classification approval.