Table of Content

28 August 2014, Volume 48 Issue 08 Previous Issue    Next Issue

Communication and Transportation

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Investigation of an Unconventional SWATH Based on Zero Wave Resistance Theory QIAN Peng,YI Hong,LI Yinghui,YU Shengjie 2014, 48 (08):  1053-1058.  Abstract ( 1013 )   Save  An unconventional small-waterplane-area-twin-hull(SWATH) ship was designed, whose twin hulls were slightly curved in an S-shape and arranged at a mean yaw angle but mirror symmetric to their common longitudinal center plane. Based on the “zero wave resistance” theory, a viscous flow theory which could solve the Reynolds-averaged Navier-Stokes (RANS)  equations was used to study the resistance performance of the unconventional SWATH ship in calm water. In comparison with a benchmark conventional SWATH ship, which features a typical torpedo-shaped body, the simulation results prove the effectiveness of the S-shaped design. The unconventional SWATH ship has much less low-speed drag than its conventional SWATH counterpart and comparable total drag at high speeds. References | Related Articles | Metrics

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Numerical Simulation of Cavitation Characteristics of a Pump-Jet Propeller SHI Yao,PAN Guang,WANG Peng,DU Xiaoxu 2014, 48 (08):  1059-1064.  Abstract ( 1169 )   Save The cavitation hydrodynamic performance of a pump-jet propeller was calculated and analyzed with the mixture homogeneous flow cavitation model based on Rayleigh-Plesset equations and sliding mesh. The effects of different rotational speed, cavitation number and flow velocity on cavitation characteristics of the pump-jet were studied. When the cavitation occurred on the blades, the propeller thrust and torque decreased significantly, thereby causing an open water efficiency decrease of 15%. For the same cavitation number, as the rotational speed increased, the pump-jet propeller blade cavitation phenomenon was more obvious. While for the same rotational speed, the smaller the number of cavitation, the- more remarkable the cavitation phenomenon was. However, when the cavitation number was greater than a certain value, the blade cavitation phenomenon disappeared.   References | Related Articles | Metrics

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Thermal Control System Design of Two-Bearing Inertial Measurement Unit Table Under Heat-Vacuum Condition CHENG Yaoqiang1a,XU Demin1a,1b,REN Hongke2,ZHANG Hong2,LIU Mingyong1a,GUO Linxiao2 2014, 48 (08):  1065-1071.  Abstract ( 977 )   Save This paper discussed the thermal control system design, test and re-design of a two-bearing inertial measurement uint(IMU) table in detail. First, it analyzed the oblique installed structure and layout. Then, it introduced the thermal design of twobearing gyroscope and quartz accelerometer based on the thermal design principle of aerospace products. Test results showed that  during high temperature period, the temperature of the gyroscope soared. By substituting the installation plate materials with bigger thermal conductivity coefficient, the gyroscope was made to work stably in its optimal range. The final test data and comparison of calibration data showed that thermal control system the design of the twobearing table fully met the requirements of the global ship. The two-bearing IMU table could provide a good temperature environment for inertial instrument, which not only ensured the working precision of inertial instrument, but also greatly improved its on-orbit working life. References | Related Articles | Metrics

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Mechanical Property and Ultimate Bearing Capacity of Ship Airbags YU Longa,LI Yaob,XIA Lijuana,DING Jinhonga,YANG Qia 2014, 48 (08):  1072-1077.  Abstract ( 1004 )   Save The general geometry deformation and principle of thin shell pressure container etc were studied. A mathematical model of deformation, bearing force and inner air pressure of a loaded airbag was built. The membrane material property was determined by the uniaxial tensile test. The unified model could predict mechanical property and ultimate bearing capacity of the loaded airbag. Some cases were calculated and compared with the experimental data. The model was validated  as a guidance for safety launching application.   References | Related Articles | Metrics

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Airbag Simulation and Application Based on Corpuscular Particle Method WANG Na1,PENG Xiongqi1,ZHANG Yuan2,PAN Feng2,LU Hongsheng2 2014, 48 (08):  1078-1083.  Abstract ( 1364 )   Save Based on the corpuscular particle method (CPM), the pressure vessel filling process and out-of-position pendulum test with an airbag were simulated in LS-DYNA. The simulation results were compared with experimental data to verify the validity of the CPM in simulating airbag deployment process. Then, the deployment of airbag on the occupant restraint system was simulated with the CPM by establishing a frontal impact sled model. The comparison between experimental and numerical results of the dummy head injury indicates that the CPM is capable of simulating the airbag deployment process, providing a method for the development of the restraint system and simulation of engineering practice.   References | Related Articles | Metrics

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Characteristics Analysis of Structural-Acoustic of Cylindrical Shell with Prestress in Local Areas CHEN Luyun1,LI Leixin1，2,ZHANG Yufang1 2014, 48 (08):  1084-1089.  Abstract ( 865 )   Save The influence of existing prestress on structure dynamic response and acoustic radiation were investigated. Based on Flügge’s cylindrical shell equations, the strain-displacement equation with prestress in local areas was discussed, and the structural-acoustic mathematical formulation for cylindrical shell with prestress in local areas was propored by using the variational principle. By using finite element method (FEM) and boundary element method (BEM), the numerical analysis of structural-acoustic radiation for shell structure was presented, and the influence comparison of prestress on acoustic radiation power and acoustic radiation directivity was conducted. The results show that with the existing of prestress in local areas leads to a change of local areas stiffness matrix, and the overall stiffness matrix of cylindrical shell is altered. The prestress has a significant impact on dynamic characteristics of cylindrical shell structure.   References | Related Articles | Metrics

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Sound Insulation Performance of an Infinite Orthogonally Stiffened Laminated Plate PANG Fuzhen1,3,CHEN Lin2,MIAO Xuhong1,YAO Xiongliang3 2014, 48 (08):  1090-1096.  Abstract ( 817 )   Save A theoretical model of sound transmission of an infinite orthogonally stiffened laminated plate was developed to investigate the sound insulation performance based on classical laminated plate theory, taking into account the effects of the bending and torsional movement of the stiffener. Then, by using the space harmonic expansion and the principle of virtual work, the sound transmission loss formula was derived. By comparing the predictions of the presented model with existing results of the simplified model and the platebeam combined model, the validity and feasibility of the proposed model was qualified. Finally, the influences of laying mode, angle, stiffness of layers, material loss factor and spacing of orthogonal stiffeners on the sound insulation performance were investigated by numerical calculation.   References | Related Articles | Metrics

Aeronautics & Astronautics

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Experimental Study of Starting Vortex Induced by Atmospheric Dielectric-Barrier-Discharge Plasma ZHANG Yi,LI Weipeng,WANG Fuxin,XIANG Yang,LI Zijia 2014, 48 (08):  1097-1102.  Abstract ( 764 )   Save A parametric analysis were performed on a dielectric-barrier-discharge (DBD) plasma actuator to investigate the relationship between the inducedvelocity/power-consumption and the signal wave, voltage, frequency and electrode gap, respectively. Using the particle image velocimetry (PIV) and flow visualization technique, the starting vortices induced by the plasma actuator were observed in the quiescent air, including the downstream primary vortex which is relative to the exposed electrode, the upstream opposite vortex and the secondary vorticity associated with the primary vortex. The development of the primary vortex and the opposite vortex was studied, and the mechanism of the induced starting vortices was discussed by comparing the flow visualization and PIV results with the discharge current wave. References | Related Articles | Metrics

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Thermally Induced Vibration of the Flexible Solar Wing of the Mast of Space Station KONG Xianghong,WANG Zhijin 2014, 48 (08):  1103-1108.  Abstract ( 1173 )   Save Uncoupled thermally induced vibration (UTIV) was studied for the flexible solar wing of the mast of the space station. The equivalent temperature loads were calculated and used in the UTIV analysis of the mast by the finite element mothed. Python programs were used to read, process and load the data for the coupled temperaturedisplacement analysis, static analysis and linear dynamic analysis. High efficient finite element pre/postprocessing Python programs and the finite element software Abaqus were used to complete the UTIV analysis of the mast based on multiple disciplines’ theories. The analysis results prove that the UTIV finite element analysis method is reliable and the results can be used as references for the design and analysis of the solar wing of the space station. The equivalent temperature loads calculated during the analysis can be used for the vibration analysis of the cabin and solar wings of the space station.   References | Related Articles | Metrics

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Mechanical Behavior Analysis and Experiment of Kapton Film Folding CAI Qiyao1,CHEN Wujun1,ZHANG Daxu1,PENG Fujun2,FANG Guangqiang2 2014, 48 (08):  1109-1115.  Abstract ( 1166 )   Save The relationship between contact force of the adjacent film and layer pitch of the S-fold model was deduced based on linear-elastic engineering theory. The numerical simulation analysis of the folding process was conducted in implicit static method with ABAQUS. Considering continuous and grading loading conditions, repeated elastic and elastic-plastic folding experiments on 50 μm and 125 μm film specimens were conducted to acquire the P-h curve and the creep displacement (Δh). The stress-strain curve and mechanical parameters of the film were obtained from uniaxial tensile tests, which were then applied to theoretical analysis and numerical simulation. The consistency of P-h curve obtained from the three approaches shows that the one-dimensional approximate theory is reasonable and the numerical simulation is effective. References | Related Articles | Metrics

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Stress Analysis of Composite Curved Laminate Under Loading HUANG Haojie1,ZHANG Junqi2,LIU Longquan2,WANG Hai2 2014, 48 (08):  1116-1121.  Abstract ( 822 )   Save To study the stress distribution of curved composite laminate under loading, a group of specimens were quasistaticly tested by using displacement control method. The finite element model of curved laminate was constructed by commercial finite element software ABAQUS, and the numerical model was validated through comparing with the test results. By analyzing the stress distribution under different load conditions, the following conclusions can be drawn: the main failure mode of the curved laminates under loading is delmination, and the σ33 dominates the cause of the delamination; the onset of the delamination is close to the inner surface of the curved region along the radial direction, at about 29° along the circumferential direction, on the symmetric plane along the width direction; the load capacity of the curved laminate increases with the increase of its thickness; the distance between the onset location of the delamination and the inner surface of the curved laminate becomes greater with the curved laminate being thicker, but the ratio between this distance to the thickness of the curved laminate is smaller with the curved laminate being thicker; the onset location of the delaminate is closer to the loading end of the curved laminate with the curved laminate being thicker. Key words： References | Related Articles | Metrics

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Aerodynamic Optimization Design of Adaptive Airfoil Leading Edge Based on Isight ZHOU Chen,WANG Zhijin,ZHI Jiaoyang 2014, 48 (08):  1122-1126.  Abstract ( 1335 )   Save Aimed to gain a high aerodynamic efficiency in various flight conditions, the aerodynamic optimization of the adaptive airfoil leading edge was conducted based on Isight platform. First, a modified method of original Hicks-Henne shape function was adopted to parametrically describe the leading edge. Then, Latin hypercube sampling was applied to generate the samples, whose aerodynamic performances were obtained from a series of CFD simulations. Subsequently, those simulated data sets were used to train the RBF neural network. Finally, the optimization of the objective function using the multiisland genetic algorithm(MIGA) based on the neural network approximation model was performed to achieve the optimal results. The lift to drag ratio optimization design of NACA 0006 was performed as an example using this combined strategy. The results show that the modified Hicks-Henne shape function describes the airfoil leading edge with satisfaction. The combined optimization method evidently improves the efficiency of the airfoil aerodynamic optimization procedure.   References | Related Articles | Metrics

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Numerical Simulation and Aerodynamic Analysis of Airfoil Flying over Wave Ground at High Grade Sea Condition HAN Long1,CHEN Yangling2,WANG Fuxin1,CHENG Yongsheng1 2014, 48 (08):  1127-1133.  Abstract ( 891 )   Save The 3-dimensional straight wing (NACA0015 airfoil) flying over wavy ground at high grade sea condition was studied numerically by adopting the computational fluid dynamics (CFD) method. The NS equation of unsteady incompressible flow and second order RNG k-ε turbulence model were solved in Fluent. First, the necessity of involving local wind speed and velocity of wave when researching qavy-ground-effect numerically was investigated with 2dimensional cases. Besides, the trends and reasons that aerodynamic coefficients vary with ground clearances under wavy-ground-effect were studied. Then, the aerodynamic force and the rolling moment of 3-dimensional airfoil were analyzed when the course angle between the direction of flight and local wind speed were different, and detailed description of the causes and characteristics of the rolling moment were made. After numerically researching these cases, the impact of wavy-ground-effect at high grade sea conditions on the airfoil was illustrated preliminarily, providing basic theory to aerodynamic design and flight control for WIG craft.   References | Related Articles | Metrics

Mechanical instrumentation engineering

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An Automated Planning-Based Conceptual Design Synthesis Approach LI Xiang,CAO Yuanguo,ZHANG Zhinan,XIE Youbai 2014, 48 (08):  1134-1141.  Abstract ( 719 )   Save To improve the solving efficiency of computer aided conceptual design (CACD) systems, this paper proposes a novel heuristic planning approach for automated conceptual design synthesis based on the idea of automated planning in artificial intelligence. The proposed method represented the functional knowledge of principle solution based on the stateaction method. With the proposed three integrationsolving search strategies (e.g., forward chaining integration, backward-chaining integration and forward-backward-chaining integration), the proposed methods can efficiently solve design problems. Finally, a design case of tidal power system illustrates that the proposed heuristic planning approach can successfully achieve an automated conceptual design synthesis. References | Related Articles | Metrics

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Functional Representation and Intelligent Synthesis Approach of Multi-Disciplinary Signal Systems HU Chenqiang,CHEN Yong,LIU Zelin 2014, 48 (08):  1142-1148.  Abstract ( 700 )   Save Multi-disciplinary signal systems involve the signal-transforming components in various disciplines. Creative conceptual design of these systems poses great challenge to designers who have usually been taught with the knowledge in very limited disciplines. This paper proposed a conceptual design approach for multi-disciplinary signal systems by intelligently synthesizing signal-transforming knowledge of multi-disciplinary principle solutions. It consisted of a functional knowledge representation model, which can formally represent the signal-transformation knowledge of various multidisciplinary principle solutions, and a sense-selection-action based approach for achieving the synthesis of multi-disciplinary principle solutions. Besudes, a prototype system for achieving computer-aided multi-disciplinary signal transformation conceptual design was developed,  with a knowledge base about various signal-transforming principle solutions. In addition, an example was used to illustrate the proposed approach. References | Related Articles | Metrics

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Design of a Vertical Driven Piezoelectric Vibratory Feeder SHEN Yanhua，YANG Zhigangb，LIU Yongb,TIAN Fengjunb，SU Jianga 2014, 48 (08):  1149-1154.  Abstract ( 1060 )   Save A novel vertical driven piezoelectric feeder was designed using the micrometric displacement and the big output force of the piezoceramic. The working principle was analyzed and the system dynamical model was built. Theoretical analysis confirmed the system vibration model, amplitude, natural frequency and the material movement. The distribution curve of natural frequency and the relation curve between amplitude and conveying speed were obtained through the prototype and experiment testing. The results indicate that the best working frequency of the prototype is 195 Hz, the amplitude of slide transport is between 17 μm and 27 μm and the speed can reach 123.5 mm/s, the amplitude of casting delivery is between 27 μm and 32 μm and the speed can reach 140.5 mm/s. In comparison with the same model cantilever piezoelectric feeder, the prototype of the novel feeder has better performance and smaller structure space and can satisfy industry requirements.   References | Related Articles | Metrics

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Theoretical Analysis of Flow Pulsation of Balanced Double-Stator Multi-Pump WEN Desheng,LIU Zhongxun,LIU Qiaoyan,GAO Junfeng,ZHOU Ruibin,L Jiansen 2014, 48 (08):  1155-1158.  Abstract ( 815 )   Save In order to acquire the output performance of the balanced doublestator multipump, by studying the effect of the vanes in one acting period on the  flow pulsation of the pump, the mathematic relationship between the vane number and the instantaneous flow rate was obtained. At the same time, the influence of the initial angle on the output characteristics when the inner and the outer pumps work alone was considered. The effect of lag angle on the teamwork of the pumps was also discussed. It turns out that the flow pulsation of the even vane is smaller when the acting number of balanced doublestator multipump is even and is less than or equal to nine vanes in one acting period, however, the flow pulsation of odd vane is smaller, when the acting number of the pump is more than nine. The theoretically foundation was laid for the design of balanced double-stator multi-pump.   References | Related Articles | Metrics

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Effect of Coking on Thermal Diffusion and Mechanical Property of HP40Nb Tube SHEN Limin1,GONG Jianming2,LIU Huansheng1,HUANG Yuxia 2014, 48 (08):  1159-1163.  Abstract ( 858 )   Save Based on the finite element ABAQUS code, a sequentially coupled thermal stress procedure was developed to calculate the distribution of temperature and thermal stress field of coked HP40Nb tube, and the critical depth of coking layer was predicted when the decoking measurement should be conducted. The results show that the thermal diffusion property of HP40Nb alloy deteriorates sharply with coking layer increasing. The maximum circumferential stress is along the crosssection of coking layer and HP40Nb alloy, and the stress increases initially and then decreases. Coking caused the ethylene pyrolysis furnace tube to bulge to the actual radial and rupture at local field. The critical depth of coking layer was predicted to be 2.3 mm when the decoking measurement had to be executed.   References | Related Articles | Metrics

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Digital Design and Validation of Fuel Pump with Complex Centrifugal Impeller PAN Xiao1, 2,WANG Wenping1, 2,LI Shulin1, 2,XIAO Ruofu3,PAN Changchun4 2014, 48 (08):  1164-1169.  Abstract ( 746 )   Save In order to meet the needs of the next generation refueling system , an optimizaed hydraulic model of a particular centrifugal fuel pump was developed with spiltter blade. First, the complex impeller model with best hydraulic performance was redesigned by using the CFD(computational fluid dynamics) method iteratively. Then, the full threedimensional numerical simulation was applied to the resulting model. The analysis of the internal flow shows that the splitter blade can depress the vortexes effectively. Based on optimization results, specimen products were made and tests were performed to verify the design. The comparison of test data and simulation results show that the performance of the optimized pump is superior to that of the current one. The complex impeller can improve instability of centrifugal pump at small flow and widen its range of working condition from 1.3 to 2 times of the design flow rate condition. The results of this paper can provide technical support for designing better fuel pumps for other applications.   References | Related Articles | Metrics

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Health-Index-Based Joint Optimization of Preventive Maintenance and Multi-Attribute Production Scheduling   TAO Xinyang，XIA Tangbin，XI Lifeng 2014, 48 (08):  1170-1174.  Abstract ( 916 )   Save This paper dealt with single machine which had declining health index. It introduced recursion decline factor and failure rate ascending factor to build its imperfect maintenance model. By considering preventive maintenance (PM) and job scheduling, the PM model was expanded with order delay cost, while minimum interrupt cost was proposed together with minimum maxim tardiness and minimum total tardiness to model multi-objective job scheduling. The results of a numerical example indicate that this integrated model of PM and job scheduling is valid for planning comprehensive and optimal PM intervals and job schedules.   References | Related Articles | Metrics

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Thermal Error Modeling of a Coordinate Boring Machine Based on Fuzzy Clustering and SVM YANG Jun,MEI Xuesong,ZHAO Liang,MA Chi,FENG Bin,SHI Hu 2014, 48 (08):  1175-1182.  Abstract ( 861 )   Save To investigate the effect of the thermal characteristics of a motorized spindle system on the precision of a machine tool, two thermal error modeling of a CNC boring machine spindle were proposed, and a fivepoint method was used to measure the thermal errors of the spindle. The relationships between the spindle speed and temperature field, and thermal errors were analyzed. Then the method combining fuzzy clustering and correlation analysis was presented to optimize temperature variables and select the variables sensitive to thermal error. Subsequently, the least square support vector machine (LSSVM) and multivariable linear regression analysis (MLRA) models were established for axial elongation and radial declinations. The results indicate that the fuzzy cluster can reduce the multicollinearity among temperature variables and improve the stability of the model. Moreover, the LSSVM has better generalization than MLRA under different cutting conditions, and the prediction accuracy could reach up to 90%, which could be used to compensate thermal errors of the machine. Key words： References | Related Articles | Metrics

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Inclination Sensing Characteristic Using Magnetic Fluids CAI Shaochuan1,2,WANG Kundong2 2014, 48 (08):  1183-1188.  Abstract ( 739 )   Save This paper focused on the research of static inclination measurement using magnetic fluids. First, the force analysis was performed when the magnetic fluid drop was in the symmetrical gradient magnetic field to explore the inclination measurement principle. Then, the circuit for sense and signal process was designed and a test bench was built to measure the sensibility, the range and the resolution. Finally, some factors that affect the uncertainty of the sensor were discussed. The test results verify the validity of magnetic fluid drop as transducing function mediums, which lays a foundation for the sensing and actuating devices.   References | Related Articles | Metrics

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Tolerance Analysis Method of Mechanism of Remote Center of Motion in Surgical Robot MO Zhixiang,YU Deru,WANG Shigang 2014, 48 (08):  1189-1193.  Abstract ( 992 )   Save An analysis method for the tolerance problem of the mechanism of remote center of motion used in surgical robot was conducted，which incorporated the identification and definition of the mechanical tolerance. An error propagation model was established using the direct linearization method. Besides, the absolute accuracy and repeat accuracy of the mechanism were analyzed using the probabilistic method and the deterministic method. In addition，sensitivity analysis of each error factor was conducted. The result shows that the mechanism can achieve a relatively high accuracy when using the IT6 standard designing level，and sensitivity analysis can find out the key factor that affects the mechanism accuracy. References | Related Articles | Metrics

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Numerical Analysis of Reverse Pumping Rate of Rotary Lip Seal by Finite Element Method   JIANG Huasheng1，2，PENG Xudong1，MENG Xiangkai1，SHEN Mingxue1 2014, 48 (08):  1194-1199.  Abstract ( 1011 )   Save In order to accurately predict the reverse pumping rate of rotary lip seals, a mathematical model of lip seal under steady state was developed adopting the JFO cavitation boundary condition based on mass conservation. The lubrication governing equation was solved by streamline upwind finite element method. Then, the effects of operating parameters and microundulation structural parameters on the reverse pumping rate were investigated. The results show that the reverse pumping rate increases with the rotary shaft running speed, while decreases with the sealed pressure, or even turns to leakage rate. The reverse pumping rate increases with the microundulation circumferential amplitude, wavelength and the maximum circumferential deformation, while decreases with the microundulation axial profile amplitude. The lip seal shows reverse pumping effect only when the location of the maximum circumferential deformation is close to the oil side, and the closer it is to the oil side, the larger the reverse pumping rate is. Key words： References | Related Articles | Metrics

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Spiral Tool Path Generation for Pocket Machining LIN Jintao,BI Qinzhen,WANG Yuhan,SUN Chao 2014, 48 (08):  1200-1204.  Abstract ( 1316 )   Save A novel methodology based on partial differential equation (PDE) was presented in this paper because the existing tool path generation methods for pocket machining cannot meet the requirements of high speed machining(HSM). First, a PDE was introduced by a twodimensional steadystate temperature equilibrium equation. The boundary of the pocket was offset by a tool radius as the boundary of the PDE, and the boundary condition was assigned to zero, based on which a toolpath generation model was established. Then the inner region was divided into the triangle mesh, and finite element method (FEM) was introduced to solve the PDE. Therefore, the isometric curves was obtained from the solution of the PDE. Finally, the isometric curves were connected to generate the spiral tool path. An experimental implementation was conducted to prove the validity of the proposed method. The results show that the proposed method can apparently improve the movements of the machine tool with higher efficiency. References | Related Articles | Metrics

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Research on Management Models of Foreign National Parks ZHOU Wuzhong,XU Yuanyuan,ZHOU Zhicheng 2014, 48 (08):  1205-1212.  Abstract ( 1898 )   Save The research on the management models of national parks has always been a hot issue in the field of natural heritage management in recent years. Based on the management experience of the foreign national parks, this paper generalizes four typical management models, which are centralization management model based on national identity building, comanagement model driven by citizens' recreations, selfmanagement model started from nature conservation and sustainable management model oriented by ecological tourism. These four models are further studied in detail by using an analytical framework of constructing forces, implementation means and developing resistances. At last, this paper presents the inspiration of the foreign experience for constructing the management models of China's national parks. References | Related Articles | Metrics