Table of Content

10 May 2020, Volume 31 Issue 09

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On Atomic and Close-to-atomic Scale Manufacturing——Development Trend of Manufacturing Technology

FANG Fengzhou

2020, 31(09):  1009-1021. 

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This paper present the manufacturing development history, described three phases of advancement in, and indicated the main trend of manufacturing development, namely, ACSM, which would be of great significance in developing future technologies and high-end components manufacturing. The ACSM main issues to be explored were discussed and the relevant suggestions and measures were who provided.

Structural Optimization of Electric Vehicle Battery Systems under Pole Side Impacts

CHEN Tao1;LI Ningning1;LI Zhuo1;LI Qiqi1;CHEN Shaowei1;ZHANG Qian2

2020, 31(09):  1021-1030. 

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The short-circuit failure analysis of power cells was introduced into electric vehicle pole side impact researches, the dynamic topology optimization method was used to optimize the design of battery system structures. A new battery system structure with better load paths was built based on the topology results, and the thickness distribution was optimized by orthogonal test. Compared with the original structure, the new structure greatly reduces the structural distortions and battery failures under pole side impacts without increasing mass, and significantly improves the crash safety of the power batteries.

Numerical Simulation Investigation on Ballistic Resistance of Aluminum Alloy Triangle Corrugated Sandwich Plates against Blunt-nosed Projectile Impacts

YANG Yonggang;Tian Rui;LU Mingjian;DENG Yunfei

2020, 31(09):  1031-1036,1042. 

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In order to study the impact resistance and failure mode of aluminum alloy triangular corrugated sandwich plates impacted by blunt-nosed projectiles, the numerical simulation model of plates impacted by projectiles were established by finite element software ABAQUS/Explicit, and also the validity of the model and its parameters were verified by tests. Based on the results of numerical simulation, the influence laws and mechanism of the geometry on the protection performance, failure mode and energy absorption of triangular corrugated sandwich plates were analyzed, and also compared with monolithic plates of the same area density. The results show that the structure of target has effects on the impact resistance, and also the impact resistance of triangular corrugated sandwich plates is lower than that of monolithic plates. Moreover, the impact resistance of triangular corrugated sandwich panels may be significantly improved by increasing the angles of the core topology, and the geometrical sizes of the plates also affect the failure mode and energy dissipation characteristics.

Strain-stress Relation of Medium-thickness Steel Plates Including Necking Stages

ZHU Chuanmin1;GU Peng1;LIU Dinghao1;ZHANG Heng2

2020, 31(09):  1037-1042. 

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In order to make up for the defects of extensometer in measuring necking processes, a cross-sectional analysis method was proposed based on three dimensional digital image correlation(3D-DIC) technique. The medium-thickness steel plate QStE700 whose rolling degree was as 0°was taken as the research object, based on the cross-sectional analysis method, the sectional geometry and area during tensile processes were obtained, the necking time under tensile loading was determined, the stress-strain evolution including necking stages and the changing rules of necking area were analyzed. The modified Bridgeman equation was adopted to transform the true stress-strain curves into the equivalent stress-strain curves, and the modified equivalent stress-strain curves including necking stages were obtained. The finite element model was established based on the traditional exponential curves and the modified equivalent stress-strain curves respectively, the relationship between section area and time and the relationship between load and displacement were both obtained. It shows that the results of the finite element model based on the modified stress-strain curve are in good agreement with the experimental results, the cross-sectional analysis method based on the 3D-DIC technique is verified. This method may be applied to describe the tensile deformation processes including necking stages.

Optimization Design of RV Reducer Turning Arm Bearings

LYU Fengpeng;LI Chaoyang;HUANG Jian;CHEN Bingkui

2020, 31(09):  1043-1048. 

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In order to improve the fatigue life of RV reducer, an optimization design of crankshaft bearings was introduced based on genetic algorithm. The basic dynamic capacities of the bearings were selected as objective function. The design variables including the bearing pitch diameter, the diameter of the roller, the effective length of the roller, and the number of rollers were defined. The constraints were given on geometry, strength, lubrication and friction. The sensitivity of optimization results was analyzed. Optimal results show that the fatigue life of RV reducer may be improved by the optimization design method.

Progresses of Counter-roller Spinning Equipment and Its Applications for Large-scale Tubular Components

ZHANG Dawei;ZHU Chengcheng;ZHAO Shengdun

2020, 31(09):  1049-1056. 

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The structural style, the radial and axial adjusting mechanisms of inner and outer roller, and the rotation mechanisms of blank/workpiece were illuminated, and the typical counter-roller spinning machines and their applications were introduced. The design philosophy of rotation mechanisms of blank/workpiece for a 6-meter counter-roller spinning machine, and the distributed power and all-electric servo drive for 1-meter counter-roller spinning machine provided a certain reference significance to design and manufacture of large counter-roller spinning equipment in China.

Analysis of Influence Factors and Laws of Micro Dispensing Method Based on Surface Tensions

LIU Huifang;XU Haotian;GAO Quanxiang;QIAO Kaiqing

2020, 31(09):  1057-1064,1073. 

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In order to meet the requirements of micro-assembly manufacturing for micro-droplets and high-precision dispensing technology, a contact dispensing method was proposed based on surface tensions, the factors affecting the quality of spot gum and the size of spot gum were emphatically analyzed, and some main influence factors were studied by experiments. A micro-dispensing system and a micro-image observation system for dispensing processes were designed and built. Through the analysis of the experimental results, the influences of four factors, such as dispensing speed, pipette tip diameter, dispensing distance and glue viscosity, on the size of the gelatin and the quality of the gelatin were obtained. Through the statistical analysis of a large number of dispensing results, the successful dispensing rate of the system is calculated to be about 92.7%, and the analysis clarified the reasons for the dispensing failure and the causes of irregular shaped spots.

Research on Influence Factors of Cold Roll-beating Forming Forces of Leadscrews

LI Yuxi1,2;LI Yan1;CUI Limu1;MIAO Zhihong1

2020, 31(09):  1065-1073. 

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A finite element simulation model was established on the basis of the cold roll-beating forming principles of the leadscrew to study the relationship among the radius of the rolling wheel, the fillet radius of the rolling wheel, the amount of beating, and the deformation forces. The single and multiple rolling forming processes were obtained through simulation and obtaining of the deformation force varying laws with the radius of the rolling wheel, the fillet radius of the rolling wheel and the amount of beating. Through the orthogonal test, the influence laws of the amount of beating, the rotational speed of the rolling shaft, the thickness of the rolling wheel and the rotational speed of the workpiece on deformation forces were studied. The change trend of the measured forming forces was basically consistent with the simulation results, and the correctness of the finite element simulation model was verified by the experiments which were carried out on the self-designed cold roll-beating forming leadscrew equipment.

Simulation and Analysis of a New Type Reciprocating Pump Driven by a Combination of Cam Mechanisms and Fan-shaped Gear-racks

HOU Yongjun;WANG Bin

2020, 31(09):  1074-1079,1088. 

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In view of complex structure of traditional reciprocating pumps, large flow fluctuation and short life of cam drive reciprocating pumps, etc.，a new type reciprocating pump driven by a combination of cam mechanisms and fan-shaped gear-racks was proposed. the reciprocating movements of the reciprocating pump were driven by the alternating work of the cam mechanisms and the fan-shaped gear-rack mechanisms, which realized the piston uniform acceleration-uniform speed-uniform deceleration movement laws. The motion equation of the piston was established, and the influences of the flow characteristics and phase error angles of the reciprocating pump on the flow pulsation was analyzed with the example of the triplex reciprocating pump. And the dynamics simulation model of the triplex reciprocating pump driven by a combination of cam mechanisms and fan-shaped gear-racks was established, and the motion characteristics of the piston under the hydraulic end load was discussed. The results show that the flow pulsation rate of triplex reciprocating pump driven by a combination of cam mechanisms and fan-shaped gear-racks is only 1.68%,which reaches the effectiveness of the crank-slider mechanism reciprocating pump with air-bag action.The phase errors have some influences on the flow pulsation, and they should be controlled within ±30′. The simulation results verify the rationality and feasibility of a new type reciprocating pump driven by a combination of cam mechanisms and fan-shaped gear-racks.

Strain Numerical Simulation and Torque Imbalance Analysis of Remanufactured Motors with Mixed Stator Core

SONG Shouxu1,2;HU Mengcheng1,2;DU Yi1,2;LUO Rundong1,2

2020, 31(09):  1080-1088. 

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A permanent motor remanufacturing method was proposed, the components such as the casing, the end cover and the rotor were retained, and the stator was replaced by a hybrid stator core formed by axially laminating of amorphous alloy and silicon steel. Taking a hybrid stator core remanufacturing motor as object, the axial distribution of the no-load gap magnetic flux density was analyzed; the radial force density corresponding to the amorphous alloy stator and the silicon steel stator was calculated, and the strain numerical analysis of remanufactured motor was analyzed by the electromagnetic-mechanical coupling model; the axial distribution law of unit electromagnetic torque of remanufacturing motor was studied; the formula for calculating electromagnetic torque of remanufactured motor was deprived, and the torque imbalance caused by the unequal electromagnetic torque between amorphous alloy stator and silicon steel stator was found; the influences of torque imbalance on rotor core were analyzed. The remanufactured motors were fabricated and subjected to a vibration test, and the testing results confirm the correctness of the analysis.

Forming Laws of Continuous Fiber Composite Filaments in 3D Printing

FAN Congze1,2;SHAN Zhongde1;ZOU Guisheng2;ZHAN Li1;LIU Xiaojun1

2020, 31(09):  1089-1097. 

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For the 3D printing of continuous fiber reinforced thermoplastic resin composites, the flowing mechanism of the resin in the screw extrusion processes together with the impregnation behavior of the resin at the fiber interfaces were studied. The effects of screw rotating speads and traction speeds on the forming diameter and fiber content of the composite filaments were revealed. The actual impregnation time and theoretical complete impregnation time were used to jointly characterize the impregnation degree of the resin to the fiber. The interface morphology of the composite filaments was observed. It is showed that the internal voids in filament with high impregnation degree is less, and the resin and fiber are more closely combined. After 3D printing, when the degree of impregnation is increased from 17.25% to 40.02%, the tensile strength of the composite specimens is increased from 132 MPa to 160 MPa accordingly with an increasing rate of 21%. Furthermore, the dynamic mechanics analysis(DMA) test was carried out on the forming parts, the testing results show that, the specimen with higher impregnation degree has higher storage modulus and loss modulus, which indicates that the degree of interface bonding between the fiber and the matrix is improved.

Design and Mechanics Analysis of Biodegradable Polymer Vascular Stents with High Radial Supporting Property

WEI Yunbo;ZHAO Danyang;WANG Minjie;LI Hongxia

2020, 31(09):  1098-1107,1130. 

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Based on the study of the relationship between strut angle of a stent and the radial supporting strength, a novel design method was proposed herein. Specifically, unequal-height supporting rings were used to increase the strut angle after expansion and furthermore improve the radial strength. Using this method, three kinds of biodegradable polymer vascular stents were designed. Radial strength, radial recoil, axial foreshortening and bending stiffness of the three stents were analyzed by finite element method and compared with Abbott bioresorbable vascular scaffolds(BVS). The influences of the structures on properties of the stents were studied. The radial strength of the designed JS(J-type stent), OCS(open C-type stent) and CCS(closed C-type stent) is as 14%, 34% and 42% higher than that of the BVS, respectively. The recoil of the designed stents is about 21% lower than that of the BVS. Meanwhile, all the designed stents have no axial shortening. The bending stiffness of the JS and OCS, which have open cells, is comparable to that of BVS and is about 73% lower than that of the CCS, which has closed cells. The radial supporting strength and radial recoil mainly depend on the structural form of the supporting rings. These two properties may be effectively improved by employing unequal-height supporting rings. The axial foreshortening is mainly determined by the structural form and the connection positions of the bridges. The axial shortening of the stents may be avoided by using bridges with curved structures and setting the connection positions in the middle of the straight section of the supporting elements. The bending stiffness is mainly affected by the connection form between the bridges and the supporting rings. The bending stiffness is lower if the stent has open cells.

Bending Deformation Prediction Method of Soft Actuators with Pneumatic Networks

FAN Xu;DAI Ning;WANG Hongtao;DING Longwei;XIE Shaohui

2020, 31(09):  1108-1114. 

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As the key components of the soft robot, the pneumatic soft actuators possessed the property of bending motions under the action of air pressure. However, there were lack of proper methods to the research of bending deformation of the actuators. Firstly, based on the analysis of the bending deformation principles of the pneumatic networks with soft actuators, the mathematical model of the single-airbag bending angles was built and the bending characteristics of the soft actuators was analyzed. Secondly, the bending deformation prediction model of the single-chamber and multi-chamber soft actuators was set up. Finally, the availability of the bending deformation prediction model was verified via the finite element simulations and physical experiments respectively.

Salt Spray Aging Property of Molded Parts under Different Processing Parameters and Ultrasonic Vibrations

LIU Ying;BI Jie;YU Tongmin

2020, 31(09):  1115-1122. 

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For thoroughly analyses of the aging factors affecting on the injection molded parts, the rectangular shell parts with standard tensile sample at the bottom, whose injection mold with ultrasonic assisted vibration system were designed and manufactured. The isotactic polypropylene material was selected in the molding experiments, which were carried out under different processing parameters and ultrasonic vibration actions. And with the molded parts, the neutral salt spray aging experiments were carried out. Meanwhile, by means of wide angle X-ray diffraction, Fourier transform infrared spectrometer analysis, scanning electron microscope and the tensile test, the mechanics property of the parts was evaluated and the relationship between the formation of condensed state structure and anti-aging properties of the samples was characterized. Furthermore, the influences of melt temperature, molding temperature, holding pressure and ultrasonic power on the formation of condensed structure and the anti-aging properties were studied. Results clearly show that the salt spray aging resistance of the parts will be degraded by the rise of melt temperature, while the salt spray aging resistance of the parts will be improved by the rise of molding temperature and packing pressure. Increasing the ultrasonic power may increase the crystallinity inside the parts, but when the ultrasonic power exceeds 200 W, the tensile strength of the parts is greatly reduced. It can be seen that excessively high ultrasonic power is not conducive to the formation of condensed state structure with optimal anti-aging properties inside the parts.

Investigation on MVEM under Actual Working Conditions

DUAN Lian;YUAN Xiayi;ZHANG Yan;ZHU Liang;JIANG Liang

2020, 31(09):  1123-1130. 

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A method of improving MVEM simulation accuracy was proposed based on test parameters of the engine under real operating conditions. Firstly, the performance of a naturally aspirated engine in the mass production states was measured on the five-motor bench. The engine water temperature, engine speed, engine cylinder pressure, intake port pressure and temperature, intake manifold pressure and temperature, fuel volume flow, power generation flywheel end torque, exhaust manifold pressure and temperature, exhaust manifold excess air coefficient, exhaust pressure and temperature after three-way catalysis were obtained from the tests. Secondly, the model was created and calibrated based on the vehicle environment boundary by Amesim/MATLAB software combined simulation. The results show that the maximum errors between the predicted results of the calibrated MVEM and the actual test ones may be controlled within 8%.