## 6 Conclusions  
In order to improve the load-carrying capacity and versatility of the permanent magnet thrust bearing, this paper has proposed a new modular multi-unit cell permanent magnet thrust bearing based on the design concept of bionics and a modular design scheme. By generalizing the unit cell structure, it can be constructed according to varying requirements, with different layers of nested and cross permanent magnet thrust bearings. The proposed bearing has been verified through theoretical calculations, finite element simulations, and experimental testing. (1) Based on the design concept of bionics and referring to the structure of honeycombs, this paper adopted a modular and unit cell (composed of four permanent magnets and made universal) combination approach to construct different nested and cross structural configurations of permanent magnet thrust bearings, thereby enhancing the adaptability of permanent magnet thrust bearings in different scenarios. (2) The theoretical model of the novel modular multi-unit cell permanent magnet thrust bearing was developed using the equivalent magnetic circuit method. By applying the principles of virtual displacement and virtual work, computational expressions for bearing capacity and stiffness were established. This theoretical model extends the traditional single-layer cross-nested structure to accommodate multi-layer cross-nested configurations, improving the model's applicability. Figure 14: Stiffness comparison of permanent magnet thrust bearing. (3) The bearing performance of the proposed permanent magnet thrust bearing was verified through finite element simulations and experimental testing. Based on the practical application scenario of ship spindle propulsion, a permanent magnet thrust bearing experimental platform was built, and a modular permanent magnet thrust bearing with a four-layer cross-nested structure was constructed for validation. The experimental results show that the maximum bearing capacity of the prototype is 48.45 kN, with a 7.3% error relative to the theoretical value and a 4% error relative to the simulation solution, demonstrating good accuracy. Benefiting from the advantages of permanent magnet thrust bearings, such as quiet operation, vibration damping, and high rotational speed, this paper expands the traditional low-load permanent magnet thrust bearing to higher load ranges. The proposed modular multi-unit cell permanent magnet thrust bearing shows promising potential for applications in ship spindle propulsion. However, the existing range of applications for permanent magnet thrust bearings is still limited. Furthermore, due to the large quantity of permanent magnet materials used, the cost remains high compared to traditional bearings. In future research, efforts should focus on reducing the use of permanent magnet materials while maintaining load-carrying performance, in order to improve the competitiveness of permanent magnet thrust bearings in the market. The permanent magnet thrust bearing designed in this paper is a passive system. In the future, researchers in this field can explore the combination of permanent magnets and active control systems for the design of permanent magnet thrust bearings, so that the high efficiency of permanent magnets and the high precision of active control systems can be utilized at the same time, for example, the use of a passive permanent magnet structure in the substrate structure, and the use of active control systems in axial and radial precision control, so that a larger load-bearing capacity can be achieved based on the artificial active control system stiffness and other properties to meet the needs of more scenarios/conditions. This would allow the use of an active control system for precise axial and radial control, thus realizing a higher load-carrying capacity and artificial stiffness of the active control system to meet the needs of more scenarios/properties. Conceptualization, X.Y. and W.Y. ; Methodology, X.Y. and W.Y. ; Software, Q.W., Z.Y. and X.S. ; Validation, X.Y., Q.W., Z.Y.