Advanced Materials Research Vols. 834-836

Abstract: Single-sided Linear Induction Motors (SLIMs) have been widely used in various applications for demanding direct motion or wheelless contact, e.g, the maglev transportation, in which SLIMs are employed as the traction component. Due to its special structure, the SLIM will generate attractive force as it generates thrust force. Within limited input power, in order to maximize the thrust force and restrict the attractive force, a half region dynamical slip-frequency(HRDSF) control scheme for SLIM is proposed. If SLIM is operated under acceleration or deceleration operations, slip-frequency is controlled in the high slip-frequency region close to the maximum thrust point in order to obtain the maximum thrust, and if SLIM is operated under coasting operation, slip-frequency is automatically adjusted at large value to generate a particular thrust corresponding to moving resistance, and the attractive force values, meanwhile, are kept at small values. The validity of the proposed method are verified by both simulations and experimental tests.

Abstract: The water cavity model of engines cylinder head with 4 cylinders was reconstructed by Imageware and UG through slicing method. The reverse design methods used for complex interior structures surface were explored based on slicing method through remodeling the water cavity. The technologies of reverse design such as the measurement method of points cloud, points cloud data treatment and water cavity remodeling were studied. CFD analysis of water cavity model was done by SolidWorks Flow Simulation, the problems and reasons which may be in water cavity model were pointed out.

Abstract: In view of the existing problem of the traditional aluminium ingot stacking practices, it was important significance to research and develop a stack-manipulator that includes various functions to do portage and stack. According to the demand of stacking, the motion system of the Stack-manipulator based on four degrees was finished. The kinematics equation of the manipulator was set up using the D-H theory, On this base, Some of the kinematics problems of this stack-manipulator were discussed and these reliable basis were provided for the research of the manipulators dynamics and control and trajectory planning.

Abstract: This paper mainly explores the numerical simulation of flow and temperature fields in the shell-side of the radial heat pipe heat exchangers (HPHE), using CFD software-FLUENT. Field synergy principle is applied to analyze heat and mass transfer mechanism of heat exchangers; also, the influence of the variation of principle constructor parameters of heat exchangers on the field synergy effect and heat exchange performance has been studied. It has been found that better performance of heat exchangers is achieved with better field synergy effect; in the context of increasing transverse and longitudinal tube pitches within certain values of data, the heat transfer coefficient decreases as synergy angle increases. Variation of fin height has little effect on synergy angle, but it would decrease the heat transfer coefficient at unit pressure drop (k/Δp) as it increases; as fin pitch increases, the synergy angle first decreases and then grows, while k/Δp first increases and then decreases. The optimal ranges of heat exchanger structure parameters values were found.

Abstract: Computational grids of the complex internal flow passage in air pre-filter were generated, using the partitioned mixed grids. Based on the method of user-defined functions controlling sliding mesh, a program of defining moving boundary was proposed, and numerical simulation of the rotor movement transient controlled by the flow field of air pre-filter was achieved. Based on the theory of Euler-Lagrange phase flows, stochastic particle trajectory model and cell source method were adopted to calculate the trajectories and concentration distributions of particle phase in air pre-filter.

Abstract: Based on the advantages silicon drift detector (SDD) and avalanche photo diode (APD), a droplet-like avalanche drift diode detector (DADD) is proposed. Firstly, the overall structure of the DADD has been designed considering the parameters of bow-shaped curves, distance of drift ring, extra biased voltage and width of drift ring. Secondly, the surface potential of DADD has been simulated and obtained the relation of dark current of drift ring and voltage drops between different drift rings. In addition, static structure analysis and steady state thermal analysis have been implemented. The simulation results show that, the DADD has a good structure and features with high gain, smaller output capacitance and high photon counting capacity, which is appropriate for the pulsar navigation system.

Abstract: Traditional agricultural machinery design methods usually go through longer-design cycle and can hardly make good use of existing knowledge and experience. In view of this problem, parametric design theory and knowledge-based engineering were applied to the disc-scoop-type metering device designed to improve the design experience and reuse design knowledge. Through the knowledge-based parametric design method, the design framework model of disc-scoop-type metering device was put forward. The knowledge library on the basis of design rules and characteristic similarity-based case library were created, and disc-scoop-type metering device parametric design system based on knowledge had been developed on the platform of Pro/Engineering. The rapid design for knowledge-driven model of disc-scoop-type metering device was realized. The specific design examples clearly indicated that the establishment of the system considerately improved the quality and efficiency of the design.

Abstract: In process planning of machined part, three-dimensional process intermediate models are necessary for process design, documentation, and downstream applications including clamping design, NC programing, and process analysis. An automatic process intermediate model generation method is proposed in this paper for machined part represented in B-Rep solid model. Machining features are recognized and classified according to process type. Process plan is expressed in terms of machining features and feature surface modification operations in solid model. Local modification operations are applied to part model to move, replace or remove feature surface resembling machining process. Process intermediate models are generated automatically in a batch manner by applying geometry and topology modification operations directly on B-Rep model for each machining operation. The proposed algorithm is implemented in a CAPP tool developed in solid modeler ACIS.

Abstract: To reuse 3D CAD models more efficiently, a new 3D CAD model retrieval algorithm based on accessibility cone distributions is proposed. Firstly, a sufficiently large number of random sample points on surface of 3D CAD model are taken and the normal direction of each sample point is recorded. Then, the accessibility cone of the given sampled point is computed. Secondly, a planar grid is constructed to express the accessibility cone distribution by obtaining a statistic data of the sampled points. Lastly, the L₁ distance metric method is taken to compute the similarity between the two accessibility cone matrices, which can give the similarity coefficient for two compared 3D CAD models. Experiments results show that the algorithm can effectively support 3D CAD model retrieval, and the efficiency meets the requirement of engineering application.

Abstract: Ice loads is one of the most important parameters which should be taken into consideration for arctic structures. Ice load highly depends on the ice thickness. It is always recommended to consider the ice thickness data from field observations. However if data is not available it is necessary to calculate the thicknesses of ice level. Calculation is also important for the areas where the thermal fluxes through structure should be taken into the consideration. In this work numerical simulation of Stefan problem for determining of ice level thickness is presented. The results show good correlation between empirical, experimental data and the results from finite element simulation of Stefan problem.