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The drilling of multi-layered structural members has been a crucial process in aeronautic manufacturing. The burr formation on layer surfaces, especially on inter-layer surfaces, causes extra amount of deburring operations which waste time and cost. The inter-layer burr formation depends greatly on the size of the inter-layer gap which results from different deformations of the upper layers and the lower layers during a drilling process. Based on the theory of plates and shells, this paper discusses the drilling process of two stacked circular Al-2024T3 plates with edges built-in. The dependence of the inter layer gap formation on the pressing parameters and the axial drilling force is also discussed in this report.

We investigate the behavior of the snowline in a protoplanetary disk and the relationship between the radius of the snowline and properties of molecular cloud cores. In our disk model, we consider mass influx from the gravitational collapse of a molecular cloud core, irradiation from the central star, and thermal radiation from the ambient molecular cloud gas. As the protoplanetary disk evolves, the radius of the snowline increases first to a maximum value Rmax, and then decreases in the late stage of evolution of the protoplanetary disk. The value of Rmax is dependent on the properties of molecular cloud cores (mass Mcore, angular velocity ω and temperature Tcore). Many previous works found that solid material tends to accumulate at the location of the snowline, which suggests that the snowline is the preferred location for giant planet formation. With these conclusions, we compare the values of Rmax with semimajor axes of giant planets in extrasolar systems, and find that Rmax may provide an upper limit for the locations of the formation of giant planets which are formed by the core accretion model.

This paper presents three important electromagnetic parameters design principles in modeling a large canned motor such as the canned motor inside the nuclear reactor coolant pump. The performances of the canned motor within the nuclear reactor coolant pump are also analyzed by establishing the two-dimensional transient electromagnetic field model. The simulation result of magnetic flux density distribution of canned motor is very close to practical situation. Simultaneously the efficiency, power factor and break-down torque of canned motor are analyzed through two-dimensional electromagnetic field finite element method.

Hardened AISI 1045 steel implemented in machine tool spindle was previously ground using grinding operation. This research aims to address the feasibility of hard turning AISI 1045 using PCBN tool with chip breaker under dry condition. Chip morphology, cutting force and temperature were measured, analyzed and correlated with machining parameters. Experimental results demonstrate that serrated chips are generated at high speeds, high feed rate is an assistant to promote serrated chips, and chip breaker can help break chip into acceptable lengths. Cutting forces were characterized with periodic fluctuation along three directions as chips are serrated. Temperature at machined zone can reach as high as 1200°C, which indicates that adiabatic shear bands can be successfully achieved during the machining of hardened AISI 1045 steel without applying lubricants.