Optimum Design of TFLM with Constraint to Maximize Thrust Force, Minimize Detent Force for Weight Reduction Using Characteristic Function
This paper presents optimum design of transverse flux linear motor(TFLM) for household electric refrigerator. We use a characteristic function, table of orthogonal array and three-dimensional equivalent magnetic circuit network (EMCN) method to explain correlations between the objective function and design variables, maximize thrust force and minimize detent force for weight reduction. This paper procedure is validated by the comparison between experimental and calculation results
Lightweight design of an in-wheel motor using the hybrid optimization method
An increase in the unsprung mass is a critical issue for an electric vehicle driven by an in-wheel motor. The mass increase will cause the ride quality and comfort to deteriorate. To decrease the unsprung mass, a hybrid lightweight design method including size optimization and topology optimization is employed for the in-wheel motor. The two optimizations are carried out in sequence. First, the finite element method, the response surface method and the particle swarm optimization algorithm are employed in the size optimization design of the in-wheel motor. After this step, the mass of the in-wheel motor is reduced to 2.7448 kg, while its rated torque and losses are almost unchanged. Second, according to the above optimization results, topology optimization using the method of variable density is employed for the supporting frame of the stator of the in-wheel motor, which is the non-magnetic area. The material which is grade 45 steel is analysed. The optimization results show that, after optimization and treatment, the mass of the supporting frame is reduced to 1.069 kg, i.e. 63.11% lighter than before. Then, structural strength verification is carried out. Considering the above two optimization steps synthetically, the total mass of the in-wheel motor with a grade 45 steel supporting frame is reduced by 3.5547 kg, which means that it is 13.623% lighter than the original structure. Calculation of the transient torque and losses show that, after optimization, the total loss is reduced by 1.87%, and the torque by only 1.8%. Therefore, the hybrid optimization method studied in this paper works well for the lightweight design of an in-wheel motor.
Cooperative Collection Development
The author discusses cooperative collection development from an historical perspective and examines some of the projects conceived and implemented during the past forty years. In many cases the projects failed even after years of concentrated effort. However, more important than these failures are new efforts that are being made. The major focus of this article is on both current regional projects and the more broadly based ARL-sponsored North American Collections Inventory Project. The author discusses these efforts and offers some specific judgments regarding the possibility that these projects will lead to a truly successful coordinated collection development project on a national basis.