Table of Content

10 November 2015, Volume 26 Issue 21

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Tooth Surface Model Construction and Error Evaluation for Tooth-trace Modification of Helical Gear by Form Grinding

Wang Zhonghou, Song Xiaoming, He Weiming, Li Gang, Zhu Wenmin, Geng Zhi

2015, 26(21):  2841-2847. 

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When grinding of helical gears with tooth to tooth, contact lines changed all the time, the additional movement caused the tooth to produce “distortions of modification”. Based on the facts, this paper presented a high precision establishment method of tooth flank. Firstly, the actual contact line equation of form grinding was derived by the principles of tooth to tooth. Secondly, changing the center distance values, getting multiple sets of contact line along the tooth and NURBS surface fitting was used to get tooth flank of tooth surface. Thirdly, studying the main factors affecting the accuracy of tooth surface deviation of tooth profile and helix deviation and the evaluation model of tooth errors was proposed. Then, in a longitudinal case study of drum-shaped tooth helical gear, the tooth flank of the entire process was described. Finally, by grinding experiments the accuracy of error prediction and high accuracy of tooth surface were verified.

Influences  of  Distributed  Inner-flushing  on  Performance  of  Porous-electrode  EDM

Jiang Yi, Kong Linglei, Li Qi, Ping Xueliang, Zhao Wansheng

2015, 26(21):  2848-2852. 

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The influences of  distributed inner-flushing  on performance of  porous-electrode  EDM were studied by a series of experiments. Experimental results show that the concentration of debris within discharge gap is able  to be reduced adequately by using distributed inner-flushing,such that the tool lifting and orbiting are able to be substituted.Furthermore,a tiny pulse interval can be applied and a high  material removal rate(MRR) is able to be achieved due to the high duty cycle.Experimental results also show that as the flushing flux increases,the MRR curve demonstrates a two peak-value characteristics,as a result of the dual roles of flushing on both debris evacuation and plasma channel disturbance.By means of acquiring gap voltage  and analyzing the proportion of long-term open-circuit  period to the whole machining time,it  is proved that,as the flux increases,the debris concentration is reduced to a ideal level firstly, and then a ideal level of plasma channel disturbance is achieved.

Centrifugal  Phenomenon and Its Influence  on High Speed Spindles

Rui Zhiyuan, Li Te, Lei Chunli, Hu Chibing

2015, 26(21):  2853-2862. 

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The centrifugal phenomenon  was classified  and  three representations of  centrifugal force and its influences on the dynamic and thermal characteristic of high speed spindle  were  summed up.The universality and severity of the centrifugal force were  pointed out,which verified the force was a key factor of the spindle dynamic characteristics  and a  key factor to intensify the heat generation of bearings. Meanwhile, some other influences that  might  occur due to the centrifugal expansion were  indicated as well, from the point of centrifugal expansion some references were provided to the future research work of high speed spindles.

Structure  Design  and Modal Analysis of  Embeded Temperature Measuring Tool System

Li Guanghui, Yin Ningxia, Xu Hong, Tan Guangyu

2015, 26(21):  2862-2866. 

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In order to measure the end milling  temperature  of  a  BT handle tool  system,the temperature measurement unit  was  embedded in the interior of the BT40  handle.A  three-dimensional solid model of BT40 temperature measuring tool system was established. With the aid of finite element modal analysis, the dynamic model of the temperature measurement unit was constructed as well. Under the free and constraint states,the frequencies and modal shapes were calculated respectively.The results of finite element analysis and modal experiments show that the dynamic and balance characteristics of the BT40 temperature measurement system can completely meet the demands of the actual cutting.

Structure Design and Analysis of Movement Characteristics for a New Type Wheel-Legged UGV

Zhang Lihua, Fei Lanbing, Lou Fei, Wang Kang

2015, 26(21):  2867-2872. 

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According to the movement characteristics of parallelogram links mechanism, a wheeled UGV had remarkable performance of obstacle-surmounting. The new type wheel-legged UGV overcome the defects that the previous UGV could not cross the groove by adding swing arms and planet gears. It had good adaptability to the unstructured ground. The paper described the structure of the wheel-legged UGV in details, and analyzed the movement characteristics, and established the dynamics model by using the Lagrange equation. Finally, a virtual prototype was built for a group of feasible structure size, and the simulation results based on ADAMS software verify the feasibility of the wheel-legged UGV. 

Hierarchical Ant-Genetic Algorithm-based Multi-objective Intelligent Approach for Flexible Job Shop Scheduling

Zou Pan, Li Beizhi, Yang Jianguo, Shi Shuo, Steven Y. Liang,

2015, 26(21):  2873-2879,2884. 

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A hierarchical ant-genetic algorithm-based multi-objective intelligent scheduling algorithm was proposed for flexible job shop problem. Its basic features were: (1) the approach was based on the real-time resource information of different scheduling periods; (2) its targets were completion time and machine load etc.; (3) the multi-objective optimization strategy and method were used in an ant-genetic hybrid algorithm to obtain the optimal solution. This method could be used in the periodical normal scheduling, the dynamic scheduling scenario and the situation of urgent jobs inserting. Some tests were done on the standard cases and a combined case. Compared to MOGV hybrid algorithm, the proposed approach outperformed in 25% of the test cases with a 5%~7% decrease in completion time. As for rests 75% of test cases, the above two algorithms show the same results. Therefore, with the ability of optimizing results based on the priorities of objectives and the comprehensive performance of all objective automatically, the effectiveness of the method proposed in this paper was verified.

Analysis of Coupled Vibration in Isolation System for Airborne Optoelectronic Pod

Du Yanlu, Ding Yalin, Xu Yongsen, Nie Pin

2015, 26(21):  2880-2884. 

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In order to prevent translational aircraft vibratory disturbances from transforming into angular vibration of optoelectronic pod and reduce the influences of angular vibration on the image quality and accuracy of line-of-sight(LOS), a passive isolation system was analyzed and developed. For the point that angular vibration transmissibility could not be analyzed with the model of single degree of freedom, a mathematical model of two degree of freedom vibration isolation system was established. The transfer function between translational aircraft vibration and rotational responses of optoelectronic pod was derived. The coupled vibration in isolation system with stiffness error , damping error and unreasonable layout were analyzed.These analyses provided theoretic basis for the design and assembly of the vibration isolation system. Finally, combining engineering practices, the methods to reduce angular vibration from aircraft linear vibration were proposed.

A Method for Composite Roll Profile Control Based on Quintic CVC and SmartCrown

Tang Zhong, Li Wenqiang, Tao Ye

2015, 26(21):  2885-2890. 

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In order to improve the profile control capability of rolling mill,based on the analyses of characteristics of continuously variable crown(CVC) roll contour and SmartCrown roll contour,a method for composite roll profile control was proposed based on quintic CVC and SmartCrown.Combined with the characteristics of quintic CVC and SmartCrown in the control of profile defects,these methods of decomposition and superposition were used to redefine its quadratic crown and quartic crown and control capability.Through the design example and result analyses,it demonstrates that the method effectively improves the disadvantages of profile control due to the larger roller diameter difference to the quintic CVC and advanced variable crown(AVC) roll contour.

Ultrasonic Cavitation Micro-jet Modeling and Simulation

Ye Linzheng, Zhu Xijing, Guo Ce

2015, 26(21):  2890-2894. 

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To explore the impacts of micro-jet on the wall generated by cavitation in the power ultrasonic honing, liquid compressibility was considered, the peak pressure and stagnation pressure formulas of the wall were established based on the continuity and momentum equations. CEL method was applied to establish the finite element model of micro-jet impinging wall, and the wall pressure and wall deformation were numerically studied. The results are: the peak pressure, maximum deformation depth and maximum equivalent strain of the wall all appear at the edge of the jet impingement; a about 0.11μm deep pit appears on the aluminum plate after impacted by the micro-jet, and material uplift at the edge of the pit; wall plastic deformation occurs mainly at the early stage of the impact, and the equivalent strain distribution presents in a ring. The impact of the cavitation micro-jet is advantageous to the material removal.

Integration of Machining Error Prediction and Compensation for Thin-walled Workpieces

Qiao Kai, Shu Xiaoping

2015, 26(21):  2895-2900. 

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A integration method for error prediction and compensation was established to deal with force-induced errors in NC machining of thin-wall parts. An effective mathematical iterative algorithm of errors was built. The dynamic emulation programs of deformation errors integrating with the error iterative algorithm, cutter moving and material removing were designed by using ANSYS parametric design language. Machining errors through the whole machining process might be calculated automatically. Using UG/Open API (secondary development tool in UG), the data communication interfaces between ANSYS and UG were designed. The CAD model was modified automatically according to the deformation errors. Then the NC codes including error compensation were created by UG CAM. Some key techniques for integration of out-line error prediction and compensation were also studied. It is proved in a three-dimensional milling example that the errors predicted by the APDL program are very close to the experimental results and the integrated softwares can generate automatically the NC codes including error compensation. CAD/CAE/CAM integration including out-line error prediction and compensation is effectively realized.

Development History and Present Situation Analysis of State Key Laboratories in Mechanical Engineering

Wang Guobiao, Song Jianli,

2015, 26(21):  2901-2909. 

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As one of the important carriers of the science and technology innovation of China, the SKLs in mechanical engineering played an important role in leading the development of academic advances, servicing the national major demands, and fruitful researches were carried out. The SKLs already became important bases of gathering and cultivating excellent talents and promoting high level academic exchange and cooperations, which made great contributions to the national economical and social developments. Herein, the construction history and development vicissitude of the SKLs in mechanical engineering during the past 30 years were reviewed, and the basic conditions of the 16 SKLs constructed based on universities and scientific research institutions were introduced emphatically. The present status of the SKLs in this field was analyzed from aspects of research directions, talents cultivation and team construction, and laboratory evaluation. At the same time, the future development and prospects of the laboratories were also discussed.

Research and Design of Extensible Hybrid Grinding Cloud PAAS System

Xie Zhiming, Deng Zhaohui, Liu Wei, Liu Tao, Peng Keli

2015, 26(21):  2910-2917,2922. 

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The software of computer aided manufacturing(CAM) for grinding was the soft power resources of manufacturing and processing in grinding field. Extensible hybrid grinding cloud PAAS system provided a general and extensible platform for the integration of using grinding software resources, which provided a convenient and reliable way to use CAM software resources for manufacturing enterprises with grinding by using mixed cloud computing technology. This paper designed the network and software architecture of PAAS system expounds and introduced the realization principles, functions and key technologies.The algorithms of CAM solution control were designed by using artificial intelligence， software system of grinding cloud PAAS was developed, the applications and development trends of PAAS system for grinding field were introduced too.

Action Reliability Analysis of  Operating Mechanism  in  Miniature Circuit Breaker

Chen Wenhua, Zhang Wen, Pan Jun, Zhang Tingxiu, Chen Lili

2015, 26(21):  2918-2922. 

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The operating mechanism action reliability of miniature circuit breaker was studied. The action reliability of miniature circuit breaker was investigated and the mechanism action reliability model was built at the overload breaking moment by using Monte Carlo method of mechanism reliability design theory. Meanwhile, the action reliability sensitivity of mechanism was analyzed, which gave out the variation laws of random parameters reliability sensitivity and the impacts of random parameter changes to operating mechanism action reliability. The analytical results indicate that the method used herein can analyze action reliability of miniature circuit breaker operating mechanism effectively and provide a basis for the design of miniature circuit breaker operating mechanism as well.

Study on Fabrication Method of Silicon 3D Micro-Nanostructure Based on Direct-alternating Electric Field

Jiao Xiaodong, Chao Yan, Wu Liqun, Yao Anqi, Lou Hongliang, Li Renwang

2015, 26(21):  2923-2928. 

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MaCE of silicon (Si) has a superiority and irreplaceable advantages to fabricate Si micro&nanostructures. In order to simplify technological process of controlling etching direction and fabricate Si 3D micro&nanostructures, a new method of fabricating silicon micro&nanostructures was presented by using direct-alternating electric field to control the etching direction. A direct-alternating electric field control model was formulated to study the mechanism of MaCE in the electric field, and the effects of different frequencies of electric field on the Si micro&nanostructures were discussed. An external electric field control model and an experiment were designed to study the action law of electric field intensity and direction on etching effienciency and direction.The results of micro-structure inspection demonstrate that electric field can effectively control etching direction and has the ability to fabricate Si 3D micro&nanostructures. Optimizations of the electric current density and electric field frequency range were obtained,and a new method was provided for experiments and mechanism analysis.

Significance  Analysis on Springback Infecting Factors in  Rubber Bladder Forming  Based  on  Design  of  Experiment and Grey Relation Degree

Liu Yulin, Bao Yidong, Ren Qinhu

2015, 26(21):  2929-2933. 

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Rubber  bladder forming is a kind of  important forming process for aircraft sheet metal parts.The springback problem was  of  difficulty in rubber bladder forming, and  significance  analysis on springback infecting factors might  control the springback effectively.Herein,orthogonal experimental design combined with grey relation degree was used to analyse  the significance for rubber forming springback influence factors based on the finite element numerical simulation,and a practical long straight  U-shaped part was taken for example to analyse  the influence degree on springback of these factors such as pressure, maximum volume  flow rate,maximum node rate,holding time,bending radius,sheet thickness and the rolling direction.The  analysis results  show  that  bending radius of die,pressure,sheet thickness,holding time are the main influence  factors  for rubber forming springback,and other factors have less effects.The analysis  results  are  consistent with  the experimental ones,so  the effectiveness of this method can be validated.

The Rolling Bearing Fault  Diagnosis  Method  Based  on ASTFA  De-noising  and   AKVPMCD

Yang Yu, Li Zizhu, He Zhiyi, Cheng Junsheng

2015, 26(21):  2934-2940. 

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A new rolling bearing fault diagnosis method  was  proposed. ASTFA method was applied to the vibration signal de-noising for the first time.Aiming at the defects of KVPMCD(Kriging model variable predictive model based class discriminate)  method that was  chosen one of the best related model   only  and the other correlation models' contribution to the prediction accuracy was  ignored,an improved KVPMCD pattern recognition algorithm AKVPMCD was proposed,the  AFSIA(artificial fish swarm intelligence algorithm) which had  high convergence speed, strong robustness and global optimization ability was used to optimize a variety of Kriging models,so as to improve the prediction precision. On the basis of above, a new fault diagnosis method of rolling bearings  was proposed based on ASTFA de-noising and AKVPMCD. The experimental results prove that this method can improve the precision of classification recognition effectively.

Design of  High-speed Tool Holder with Hydraulic Expansion System Driven by Centrifugal Force

Wang Jun, Ma Can, Han Yali, Zhang Chun

2015, 26(21):  2941-2945,2962. 

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Against  the centrifugal expansion mismatch of high-speed  tool holder and taper hole of  the spindle,a new type of high-speed tool holder was designed.It  had the structure of short solid taper-shank and double-sided positioning.A  hydraulic elastic expansion system driven by centrifugal force was installed on the tool holder so as to compensate difference of the centrifugal expansions. The structure principle of  tool holder was introduced herein.The geometrical parameters and interference were designed.The limit rotate speed and connection stiffness were analyzed by use of ANSYS.The research results prove  that the limit rotate speed of new  type  of tool holder is 38% higher than  that of  the same specification HSK tool holder,and the radial connection  stiffness is also improved to some extents,so this new type of tool holder  is  suitable  to high speed machining.

Research on Operation Principles and Vibration Features of New Drilling Oscillator

Tian Jialin, Yang Zhi, Yang Lin, Fan Zhe, Li You, Zhao Yun

2015, 26(21):  2946-2951. 

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A new type of drilling oscillator was proposed. According to the working principles of the oscillator, the axial pulse excitation function was deduced. Then, the axial vibration analysis model was established and the vibration characteristics were obtained. The laboratory experiments were designed according to the example parameters, and the results from the example parameters and experiments were compared, which verified the rationality of the vibration analysis model. The results show that: the oscillator can produce steady vibration with high frequency and low amplitude，which can turn static friction into dynamic friction. As a result, the problems of weight on bit transfer, drill string wear and stick slip for directional and horizontal wells may be solved effectively.

Power Function Continuous Straightening Method for Casting Strand Based on Creep Behavior of Metal at Elevated Temperature

Ren Tingzhi, Han Peipei

2015, 26(21):  2952-2957. 

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According to the recent study results of the creep behavior of metal at elevated temperature, a mathematical model of the strand deformation was developed and a continuous straightening curve was derived. The rollers were arranged along the curve, making the roll apron fully accommodate the creep behavior of metal at elevated temperature. Then the strand deformation features were presented. During the straightening process, the strain rates of the strand remained constant in the middle part of the straightening zone; while at the start and the end parts of the straightening zone, the strain rates of the strand were in the form of power function. Finally, an experimental research on the curve was carried out using a pilot roll supporting system. And the experimental material was a kind of Sn-Bi alloy to substitute the steel at elevated temperature. During the experimental process, the bending forces acting on the strand and the strains of the strand were measured. And the measurement results are in good agreement with the theoretical calculations.

Research on Three Dimensional Equivalent Elastic Constant of Layer Structure

Zhang Qinglei, Tang Yuliang

2015, 26(21):  2958-2962. 

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An equivalent formula of 3D elastic constants of composite laminates was presented herein according to three-dimensional macroscopic elastic properties of the laminated structure and the three-dimensional laminated structure theory. A modular program was also established on a MATLAB platform, this theory was applied in the equivalent of the plane ply and ring ply part of a large rotating mechanism. Inputting the elastic parameters of each single layer structure, the stiffness matrix, flexibility matrix and equivalent elastic constants can be automatically generated in the equivalent model. Then, the finite element model was built in ANSYS parametric language, the modal analysis result of the structure before and after equivalent was compared. The results show that the relative error is within 5%, which proves that the equivalent method used in this kind of layer structure is feasible.

Variation Law of Mechanics Parameters of Type Ⅰ Fatigue Crack Tip under High Frequency Resonant Loading

Gao Hongli, Zheng Huanbin, Liu Huan, Liu Hui

2015, 26(21):  2963-2970. 

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This paper explored the variation law of mechanics parameters at fatigue crack tip of compact tension(CT) specimen with type Ⅰ pre-notch based on dynamic FEM in the high frequency resonant fatigue crack propagation tests. The displacement fields, the strain fields and the SIFs at CT specimen fatigue crack tip in one stress cycle and at different crack lengths under constant amplitude high frequency sinusoidal alternating loading condition were calculated and the related variation laws of mechanics parameters were analyzed. In order to calculate the dynamic SIF at fatigue crack tip, the static SIF was calculated first, the comparing results of the static finite element analysis with the theoretical calculation show that finite element modeling and calculated method and results are accurate. Secondly, the variation law of SIF at crack tip during the process of fatigue crack propagation tests was studied by dynamic FEM. Finally, the high frequency resonant fatigue crack propagation tests were performed, and the dynamic strain gauge was used to measure the strain at crack tip during one stress cycle. The research results show that during crack stable propagation stage, the displacement, strain and SIF at type Ⅰ fatigue crack tip are the same form with the high frequency resonant load, and the displacement, strain and SIF amplitude increase with the crack growth. The error of static SIF between the calculated result by FEM and the theoretical result is as 2.51%. The maximum error of the strain at crack tip between the calculated result by FEM and the experimental result is as 2.93%.

Crashworthiness Optimization   for   Car   to   Truck  Underride Crashes in Narrow Area Overlap

Deng Shanliang, Jiang Chao, Deng Qingqing

2015, 26(21):  2970-2975. 

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Higher requirements are put forward toward RUG of commercial vehicles that is car to truck underride crashes in the narrow area overlap. Aiming at this phenomenon, considering 30%,50%,100% three kinds overlap crashes, through the topology optimization, the best material distribution form of RUG was obtained. According to results of topology optimization, a new kind of RUG was structured after elaborate design. Finally the new kind of RUG was applied to a certain type of commercial vehicle, and its crashworthiness of narrow area overlap crashes was validated.

Structure  Optimization  of  Single-Mode  Compound  Split  Hybrid  Power Train

Du Aimin, Liu Kaisheng, Zhu Zhongpan, Wang Chen,

2015, 26(21):  2976-2981. 

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Based  on a power coupling system in hybrid vehicles,a novel single-mode  compound split power train with the structure of double-row planetary gear sets  was proposed.An optimized structure was obtained by analyzing the mechanical points.Then the range  of characteristic parameter of the planetary gear set was calculated and optimized.Operating  modes and control strategy  were  analyzed based on this optimized structure.The effectiveness of this hybrid system was finally validated by the simulation.