For the high temperature superconducting (HTS) magnetic levitation (Maglev) test vehicle in china, the present NdFeB PMG has the symmetrical magnetic field distribution on the upper and lower surface. However, the vehicle only utilizes its upper magnetic field. 50% PMG magnetic field energy goes to waste, so the onboard HTSC arrays haven’t reached the best levitation performance. In order to make the HTS/PMG maglev system more efficient and reasonable, a new HTS/PMG Maglev design has been proposed based on the present PMG and the Halbach array PMG, whose PMG is called as hybrid PMG. Firstly, three magnetic field distributions of three kinds of PMG are compared using FEM. It is found that the magnetic field distribution of the hybrid PMG is more efficient for the HTSC’s maglev. The concentrating upper surface magnetic field is stronger to improve the load capability of the system. Numerical analysis and experiment are close for the present HTS/PMG system. More calculation shows that the bulk YBaCuO HTSC with the hybrid PMG has significantly better levitation performance than that with the other two PMGs. The usage of the onboard HTSC arrays is improved much and the load capability of the HTS/PMG Maglev vehicle is upgraded with the hybrid PMG.

On the requirement of high temperature superconducting (HTS) Maglev transportation application, levitation capability of bulk YBa2Cu3O7-x on the HTS Maglev test vehicle has been investigated experimentally by pulsed field magnetization (PFM) and field cooling (FC). The result showed that YBa2Cu3O7-x sample magnetized by the pulsed magnetic field behaves like a magnet in the other external field, and the magnetization direction of bulk determines its levitation force and lateral force mode (magnitude and direction) over NdFeB permanent magnetic guideway (PMG). On the other hand, static field cooling condition is with an electromagnetic field realized by Field Control Electromagnets Workbench. Two important forces of the same bulk were measured and compared with the PMG when the bulk had the same max trapped field by FC and PFM methods, and the results show the difference effects by these two magnetization methods.

An orthogonal cutting model was presented to simulate high-speed machining (HSM) process based on metal cutting theory and finite element method (FEM). The residual stresses in the machined surface layer were obtained with various cutting speeds using finite element simulation. The variations of residual stresses in the cutting direction and beneath the workpiece surface were studied. It is shown that the thermal load produced at higher cutting speed is the primary factor affecting the residual stress in the machined surface layer.

This paper focuses on developing an empirical model for the prediction of milling forces in high-speed end milling of P20 die-mold steel. The spindle speed, feed rate, axial and radial depth of cut are considered as the affecting factors. The data for establishing the model are derived from high-speed end milling experiments conducted on a 5 axis machining center according to the principles of DOE (design of experiments) method. The influences of milling parameters on milling forces are investigated by analyzing the experimental curves. Consequently, multiple-regression analysis is applied in developing the empirical model. Furthermore, the significances of the regression equation and regression coefficients are statistically tested in this paper to validate the model.

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