VP10-03 Rotor Stress Analysis of High-Speed Permanent Magnet Machines Considering Adhesive Debonding
Creators: Yuanhang Pan
Jiangtao Yang
Zhenyu Wang
Chuang Gao and Shoudao Huang
Publisher: name: IEEE
Year: 2025

The high-speed permanent magnet (PM) machines are widely used due to the merits of high efficiency and high power density. In practice, the gaps between the segmented PMs and between the PMs and shaft are filled with adhesive. However, the adhesive layer faces the risk of debonding under high speed and high temperature conditions, which has a crucial effect on the stress of PMs. For the design of high-speed PM machines, it is important to accurately evaluate the rotor strength to ensure the reliable operation of rotor at high speeds [1], [2]. However, the previous studies of rotor stress ignore the effect of adhesive debonding on rotor stress. In this paper, the rotor stress of segmented PMs is analyzed considering adhesive debonding to evaluate the rotor stress more accurately in the design stage. Firstly, based on bilinear traction separation, the cohesive zone model (CZM) is established to describe the failure behavior of the adhesive layer. The stress of segmented PMs is calculated using the CZM. Then, in the case of considering the adhesive debonding, the influence of PM segments number and temperature on the rotor stress is determined. The results show that the maximum principal stress of the segmented PMs appears at the contact position with the shaft considering adhesive debonding. In addition, with the increase of segments number, the stress concentration of the PMs is relieved. Fig. 1 illustrates the schematic structural diagram of a 48-slot 4-pole high-speed PM machine retained by a carbon-fiber sleeve. The PMs and shaft are assembled by bonding, which is same as the assembly method of segmented PMs. Fig. 2 presents the tangential stress distribution of the PMs with and without considering the debonding of adhesive. It is obvious that there is a difference in stress distribution between the two. The stress concentration is more severe when the debonding of adhesive is considered. Thus, it is crucial to evaluate the rotor stress considering the adhesive debonding in the design stage to ensure the reliable operation of rotor. More detailed analysis and results will be presented in the full paper.References: [1] G. Du, W. Xu, J. Zhu, and N. Huang, “Rotor Stress Analysis for High-Speed Permanent Magnet Machines Considering Assembly Gap and Temperature Gradient,” IEEE Trans. Energy Convers., vol. 34, no. 4, pp. 2276–2285, Dec. 2019. [2] Y. Wang, Z.-Q. Zhu, J. Feng, S. Guo, Y. Li, and Y. Wang, “Rotor Stress Analysis of High-Speed Permanent Magnet Machines With Segmented Magnets Retained by Carbon-Fibre Sleeve,” IEEE Trans. Energy Convers., vol. 36, no. 2, pp. 971–983, Jun. 2021.
The high-speed permanent magnet (PM) machines are widely used due to the merits of high efficiency and high power density. In practice, the gaps between the segmented PMs and between the PMs and shaft are filled with adhesive. However, the adhesive layer faces the risk of debonding under high speed and high temperature conditions, which has a crucial effect on the stress of PMs. For the design of high-speed PM machines, it is important to accurately evaluate the rotor strength to ensure the reliable operation of rotor at high speeds [1], [2]. However, the previous studies of rotor stress ignore the effect of adhesive debonding on rotor stress. In this paper, the rotor stress of segmented PMs is analyzed considering adhesive debonding to evaluate the rotor stress more accurately in the design stage. Firstly, based on bilinear traction separation, the cohesive zone model (CZM) is established to describe the failure behavior of the adhesive layer. The stress of segmented PMs is calculated using the CZM. Then, in the case of considering the adhesive debonding, the influence of PM segments number and temperature on the rotor stress is determined. The results show that the maximum principal stress of the segmented PMs appears at the contact position with the shaft considering adhesive debonding. In addition, with the increase of segments number, the stress concentration of the PMs is relieved. Fig. 1 illustrates the schematic structural diagram of a 48-slot 4-pole high-speed PM machine retained by a carbon-fiber sleeve. The PMs and shaft are assembled by bonding, which is same as the assembly method of segmented PMs. Fig. 2 presents the tangential stress distribution of the PMs with and without considering the debonding of adhesive. It is obvious that there is a difference in stress distribution between the two. The stress concentration is more severe when the debonding of adhesive is considered. Thus, it is crucial to evaluate the rotor stress considering the adhesive debonding in the design stage to ensure the reliable operation of rotor. More detailed analysis and results will be presented in the full paper.References: [1] G. Du, W. Xu, J. Zhu, and N. Huang, “Rotor Stress Analysis for High-Speed Permanent Magnet Machines Considering Assembly Gap and Temperature Gradient,” IEEE Trans. Energy Convers., vol. 34, no. 4, pp. 2276–2285, Dec. 2019. [2] Y. Wang, Z.-Q. Zhu, J. Feng, S. Guo, Y. Li, and Y. Wang, “Rotor Stress Analysis of High-Speed Permanent Magnet Machines With Segmented Magnets Retained by Carbon-Fibre Sleeve,” IEEE Trans. Energy Convers., vol. 36, no. 2, pp. 971–983, Jun. 2021.