This paper proposes a novel hybrid rotor permanent magnet (HRPM) machine for the performance of torque and overload capability with the constraint of the rotor diameter. In order to optimize the electromagnetic performance, an analytical model (AM) is built by the magnetic equivalent circuit (MEC) of the rotor and stator considering the saturation and leakage flux effect. A good prediction accuracy is verified by the finite element method (FEM), even in high saturation condition. Based on the AM, the characteristics of the hybrid magnetic pole rotor are analyzed by the equivalent strategy that equivalent PM remanence and thickness of single pole in rotor. Furthermore, a response surface method (RSM) for multi-variate and multi-objective optimization is adapted to improve the electromagnetic performance because of the high torque density and PM material utilization. Finally, a comparison of the torque, PM eddy current loss and anti-demagnetization performance is investigated among surface-mount PM (SPM) machine, spoke-type PM (STPM) machine and HRPM machine. The comparison results show the hybrid PM rotor machine enhances higher torque density and overload capability. Finally, a 12 slot/10 pole HRPM machine is prototyped and tested to validate the analyses.

Electric actuators with fast dynamic response and high torque density are widely used in aerospace and industrial applications. In this paper, the design and optimization of a short-term high-overload permanent magnet synchronous motor (STHO-PMSM) is presented. The rated working point is optimized according to the operating conditions of the motor. The effect of electromagnetic load on the extreme torque which mainly include ampoule number and the magnetic energy of the PM is researched. Due to the nonlinear saturation influence, the equivalent magnetic network model is established. The saturation torque discount factor is proposed to quantify the degree of the core magnetic saturation. Winding temperature model is presented to inspect the motor reliability. To verify the feasibility and accuracy of mathematical model analysis (MMA), the performance of the motor in different currents is investigated compared to the finite element analysis (FEA). A prototype motor is manufactured and tested. The results of the MMA, FEA, and experiment show that the designed motor can achieve the high performance with the 10 times overload in a short time. The method of the MMA can relatively accurately predict as well as take less time consumption.

This paper presents an analytical method for predicting the electromagnetic performance in permanent magnet (PM) machine with the spoke-type rotor (STR) and a proposed hybrid rotor structure (HRS), respectively. The key of this method is to combine magnetic field analysis model (MFAM) with the magnetic equivalent circuit model. The influence of the irregular PM shape is considered by the segmentation calculation. To obtain the boundary condition in the MFAM, respectively, two equivalent methods on the rotor side are proposed. In the STR, the average flux density of the rotor core outer-surface is calculated to solve the Laplace's equation with considering for the rotor core outer-surface eccentric. In the HRS, based on the Thevenin's theorem, the equivalent parameters of PM remanence BreB and thickness hpme are obtained as a given condition, which can be utilized to compute the air-gap flux density by conventional classic magnetic field analysis model of surface-mounted PMs with air-gap region. Finally, the proposed analytical models are verified by the finite element analysis (FEA) with comparisons of the air-gap flux density, flux linkage, back-EMF and electromagnetic torque, respectively. Furthermore, the performance that the machine with the proposed hybrid structure rotor can improve the torque density as explained.

Epoxy resins were toughened by octylamine, dodecylamine, and hexadecylamine, respectively. The curing temperature and the curing kinetics were studied by non-isothermal differential scanning calorimetry (DSC) to optimize the cure conditions. The mass ratios of the monoamine to the total mass of triethylenetetramine and monoamine were varied to obtain polymers with different compositions. The cured polymers were analyzed by DSC, scanning electron microscopy (SEM), and mechanical analyses. Shape-memory performance was evaluated by fold-deploy tests. The glass transition temperature ( T_g) decreased with increasing carbon numbers of monoamine, and the decrease in T_g scaled with the content of monoamines added in the system. The elongation increased with an increase in monoamine content and alkyl chain length. The better toughness of the monoamine-rich system was further confirmed by the results of SEM. The strain fixity ratio increased with a decrease in monoamine content. The strain recovery ratios of all systems were greater than 98%.

This paper proposes two novel hybrid rotors permanent magnet (PM) machines for the high torque density in short duration condition operation. In order to enhance the torque performance, the flux concentrated structure of spoke-type PM is employed to increase the air-gap flux density. Meanwhile, the non-magnetic connector of the rotor is employed to eliminate the magnetic flux leakage. The rotors of the conventional machines and the proposed machines are optimized by the finite element analysis (FEA). Furthermore, based on the comparisons of electromagnetic performances for the optimized machines, including the open-circuit flux density, torque, PM eddy current loss, overload capability, the characteristics of the proposed machines are analyzed. The results indicate that the proposed machine can improve the torque at rated and overload operation with growth rate 14.3% and 13.1%, respectively. Finally, a 12-slots/10-pole PM machine is prototyped and FEA is to be validated.

The yak horn analysis model is created based on the measurement and analysis of the macroscopic structural characteristics of yak horn. Then, the influences of the conical structure on the stress and strain distribution of the yak horn are analyzed using finite element method. The measurement results show that the macroscopic structure along the axial direction of the yak horn has a gradient distribution, and the steepness of the conical structure is about 42. The analysis results show that the steepness of the conical structure of the yak horn affects the distribution of stress and strain. When the yak horn model with the steepness of 42 is subjected to external load, its stress distribution is more uniform, which can effectively improve the strength and toughness of the horn. The above analysis results show that the excellent mechanical properties of yak horn are closely related to its structural gradient, and the steepness of 42 is a long-term natural optimization result, which is benefit to structural bionic design.