Table of Content

06 December 2018, Volume 29 Issue 23

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Analysis of Ink Temperature of Ink Roller Extrusion Contact Areas Based on Thermal Elastohydrodynamic Lubrication

CHU Hongyan;CHEN Libo;AN Ran;CAI Ligang

2018, 29(23):  2773-2778. 

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In printing processes， printing ink temperature and viscosity had a great influence on the printing quality. Based on the thermal elastohydrodynamic lubrication， the energy of the ink layer， the thickness of the intermediate layer and the temperature of the ink layer in the contact areas of the two ink rollers were calculated by using MATLAB. The distribution of ink temperature was studied at different locations along the contact zones between the layer thickness of a soft and a hard ink roller. The effects of loads, roll speeds and the ink materials on the maximum temperature of the intermediate layers were studied. The results show that the temperature of the intermediate layer ink is the highest at the different positions along the thickness direction of the intermediate， and the temperature is lower near the two rollers. With the increases of the loads， the maximum temperature rise of the intermediate layer increases. With the increases of the roll speeds， the temperature of the intermediate layer of the contact zones between the two rolls is not changed greatly. With the increase of the elastic modulus of the soft roll， the temperature rise of the intermediate layer is increasing.

Research on Performance Improvements of Extended-range Engines Based on DOE Technology

CHENG Xueli1;DING Shuyong2;AN Linchao1

2018, 29(23):  2778-2782. 

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Taking a 1.5L extended-range engine as the research object， the computer aided engineering（CAE） simulation model was established and calibrated， and the valve lift curves， intake manifolds and intake port structures were optimized using the DOE technology， and a comprehensive bench experimental calibration was carried out for the remodeled extended-range engines. The experimental and analytical results show that the new valve lift curves improve the low speed torques， especially when the rotation speed is as 1200r/min and 2800r/min， the torques are increased as 10% and 12% respectively. The intake port structures are optimized， and the average rolling ratio is greatly increased， which is about 1.5~2.2 times more than that of the original ones. The experimental fuel consumption value of the high efficiency zone for the optimized extended-range engines is as 250g/（kW·h）， which is nearly 3 times more than that of the original ones.

Experimental Investigation on Grinding Performance Based on EMQL Technology

LIN Jianbin;LYU Tao;HUANG Shuiquan;HU Xiaodong;XU Xuefeng

2018, 29(23):  2783-2791,2798. 

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As an EMQL grinding system was developed, the effects of charging voltages on charge to mass ratio of lubricant droplets were investigated, and the wettability and permeability of droplets were analyzed. The grinding characteristics of EMQL were systematically studied at positive and negative charging voltages. Through analyzing the microhardness and microstructure of ground workpiece surfaces, the grinding mechanism of EMQL was revealed. The results show that as lubricant is charged, the surface tension and wetting angle of lubricant droplets reduce, and increase the permeability and wettability. Compared with the conventional MQL, the charged lubricant droplets are easily to enter and cover the wheel-workpiece interfaces, which improve the lubrication and the capacity of heat transfer on the grinding areas. Under the conditions of EMQL, the positive voltages increase the relative contents of ferrites on the ground surfaces, followed by reducing the microhardness of workpiece surfaces, which produce the better grinding performance.

Residence Time Prediction of Waste Particles in Dust Suction Ports for Sweepers in RBFNN Based on Entropy Method

ZHAO Fuqiang1,2;DENG Hailong1;XIE Canming1;DONG Jing1;LI Yugui1;WANG Tie2

2018, 29(23):  2792-2798. 

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For the problems that the residence time of waste particles in the dust suction ports for the sweepers was difficult to predict due to multi-type and non-linear interaction among structural, solid phase and gas phase factors, the residence time prediction method of waste particles was proposed in RBFNN based on entropy method, which considered six factors including suction vacuum negative pressure, roller rotation speed， particle mass, particle density, particle flow rate, and diameter of the suction tubes. The factor weights solved by the entropy method were used as the input disturbance variables, and the prediction model of the residence time of waste particles was established. The results show that compared with the traditional RBFNN prediction method, the proposed method has the advantage of high prediction accuracy, and may solve the problem of difficult prediction of residence time of waste particles in the dust suction ports for the sweepers, which is helpful to improve the design level of the dust suction systems for the sweepers. 

3D Reconstruction Method of Castings Based on Monocular Image Sequences

ZHANG Hongxin;WANG Mingzhu;QIU Haoran;JIANG Jingang

2018, 29(23):  2799-2803,2814. 

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In order to realize automatic detection and identification of casting burrs based on machine vision, a 3D reconstruction method of castings was proposed based on monocular visions. The uncalibrated cameras were multi-angle rotated to grab a set of monocular image sequences of a single target. A “two-step matching” method was used to optimize the matching of feature points of adjacent images, as a result of eliminating a large number of false matching points and improving the matching efficiency of feature points. Poisson surface reconstructed was used to refine the details of 3D surface of the castings based on the 3D reconstructed point arrays. The experimental results show that the proposed method and device are simple, without the pre-calibration of the relative position between the camera and the target, which may effectively restore the detail features of the 3D surface of the castings. The method is suitable for 3D surface reconstruction of parts in machining environment.

Fast Design Technology of Reusable Part Features

ZHANG Zhuang;CHENG Xiaosheng;DAI Ning;LI Dawei;SUN Dengguang;MENG Lingyin

2018, 29(23):  2804-2814. 

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A modeling method was proposed based on mesh fusion aiming at the problems of having difficulties in reusing complex structural designs in the modeling of parts. Firstly the discrete exponential mapping(DEM) method was used to parameterize the target region of base mesh locally. Secondly the hole filling was conducted on the conditions of boundary of feature mesh by using the least-squares meshes， and then the hole filling mesh was parameterized with DEM to obtain the parameter coordinates and the normals of boundary points of the feature mesh. The boundary of feature mesh was mapped to the target region of base mesh on the base of the parameter coordinates. And the feature mesh was reconstructed with deformations by the layer-based mesh deformation optimization algorithm where the coordinates and normals of the mapped boundary points of the target region were taken as the initial deformation conditions， so that the feature mesh had a better conformality. Then the conformality maybe improved through the correction of the normals of boundary points on the feature mesh to control the expansion or contraction of reconstructed mesh volume. Finally， the feature primitive was extracted from the two meshes according to the normals and the curvatures， and then the geometric constraints were added to control the positions of the feature mesh on the base mesh so as to guarantee the relative position relationship of the two meshes. The experimental results show that the proposed method may be used in the new model design to achieve the reuse of design， which has great convenience， high efficiency and accuracy.

Tool Axis Trajectory Plannings for Flank Milling Based on AFS-PSO Hybrid Algorithm

LIU Hongjun1;WEI Yuxiang2

2018, 29(23):  2815-2820. 

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Aiming at the tool axis trajectory plannings for flank milling non-developable ruled surfaces with conical milling tools, two point offset method was used to determine the initial cutter axis vector, an error metric function under single tool position was proposed to evaluate single cutter position, the square sum of differences between the distance from each point of the cutter axis to the non developable ruled surfaces and the distance from each point of the cutter axis to the cone surfaces was minimum. In order to solve the problem of position optimization for each cutter position, an optimization scheme was proposed based on AFS-PSO hybrid algorithm. The simulation results show that the proposed method may provide simple optimization processes and high precision results for single tool position optimization, which reduces the surface envelope errors of optimized tool formed by pose collection.

Research on Multi-mode Control Strategy of Electric Active Stabilizer Bars for Electric Vehicles

LI Jiao;PI Dawei;WANG Hongliang;LI Yulong

2018, 29(23):  2821-2828. 

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As the pavement and the body status were constantly changing when the electric vehicle was in the driving processes， considering the ride comfort and roll stability of the vehicles under different driving conditions， three kinds of working modes were proposed for the electric active stabilizer bar systems， and the controller selected the appropriate operating mode according to the body status signals. Based on MATLAB/Simulink， a 14 degree-of-freedom vehicle model and the electric active stabilizer bar model were established， simulation was carried out under various driving conditions. The simulation results show that， the proposed control strategy may improve the roll stability and the ride comfort of the electric vehicles.

Development of Static Balance Test Platform for Single Blades of Controllable Pitch Propellers

WANG Chao;SU Shijie;FU Lingyi;YANG Yilin;ZHANG Chao

2018, 29(23):  2828-2835. 

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A double-weighting measurement method of barycenters and unbalance torques for blades was proposed to improve the measurement accuracy of static balance for blades. The design of the static balance test platform for single blades of controllable pitch propellers with double-layer structures was carried out based on the proposed method, and in order to assure the measurement accuracy and increase measurement ranges, the RSO method was used to optimize the upper platform structures of the test platform, which might improve the rigidity and reduce the weights. A test platform prototype was developed and the tests were carried out to measure the paddles. The results show that the static balance test platform has features of high measurement precision and repeatability, which may satisfy the requirements of static balance test for single blades of controllable pitch propellers.

Optimization Method of Process Routes for Housing Parts under Low-carbon and Low-cost Constraints

ZHANG Lei;ZHAO Xikun;JIANG Shixin;SONG Haoda

2018, 29(23):  2836-2844. 

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Aiming at optimizing the low-carbon and low-cost of process routes during the processes of process design for housing parts, the machining features of complex housing parts were analyzed. On the basis of machining step sequencing principles and machining process routes, according to the polychromatic sets theory, the “feature-step” and “feature-face” contour Boolean matrixes of the step sequencing problem were constructed. A multi-objective optimization method of machining process routes was proposed, which took the lowest total carbon emissions(low-carbon) and minimum total processing costs(low-cost) as the optimization objectives. And the optimum solution was obtained by applying improved genetic algorithm to solve the machining step sequencing problem. A housing part was taken as an example to verify the effectiveness and feasibility of the proposed optimization method.

Evaluation Method of CNC Machine's Green Degree Based on Clustering and ANFIS

WANG Yugang1;IU Shichao2

2018, 29(23):  2845-2849,2858. 

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To realize the intelligent evaluation and improve the prediction accuracy of CNC machine's green degree, an evaluation method of CNC machine's green degree was proposed based on clustering and ANFIS. Clustering algorithm based on FCM and improved particle swarm optimization were used to accomplish adaptive classification of samples and generate a training sample set for ANFIS learning. The fuzzy rules were automatically generated based on training results in order to eliminate effects of the fuzziness and randomness of the indicators. After training, the model might make inference about evaluation samples. Finally, with the experiments of the CNC machine's green degree evaluation, the effectiveness of the proposed method was demonstrated.

Modeling of Energy-saving Unrelated Parallel Machine Scheduling Problems

MENG Leilei1;ZHANG Chaoyong1;ZHAN Xinlong1;HONG Hui1;LUO Min2

2018, 29(23):  2850-2858. 

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Aiming at the unrelated parallel machine scheduling problems with mininum energy consumption, five MIP models were proposed with considering turning off and on strategy. Nonlinear models were linearized by introducing intermediate decision variables. Those five MIP models proposed were compared and evaluated detailedly under both of the size and computational complexities. The test results show that MIP models are very different in both of the size and computational complexities based on different modeling ideas. The linear model performs best based on the modeling idea of idle energy.

Process Optimization Method of Core Pre-treatment for Mechanical Parts Based on Surface Quality Requirements in Remanufacturing

KE Qingdi1;TIAN Changjun1;LI Jie1;LI Baiqing2;ZHAI Zhengshu2;ZHAN Wei1

2018, 29(23):  2859-2866. 

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Aiming at the problems that the pre-treatment processes in current remanufacturing could not be effectively matched with the subsequent processes such as detection and repair, through the investigations of existing pollutions of cores and corresponding pre-treatment processes in remanufacturing, the functions of the pre-treatment process capability in remanufacturing were obtained based on surface quality requirements. Considering the energy consumptions, the remanufacturing pre-treatment process model was established and the optimization method of cores pre-treatment processes was proposed based on surface quality requirements in remanufacturing. The gearbox housing was taken as an example with Box-behnken experimental data, the optimized model was established in ultrasonic cleaning pre-treatment processes. And optimized process scheme was proposed to verify the feasibility and effectiveness of the proposed model and method under the different surface quality requirements.

Construction and Implementation of Intelligent Transparent Automobile Factories

YANG Yixin1，2;YUAN Zhaocai2;PI Zhibo2;XIA Wei3;JIANG Chao1;GUO Konghui1

2018, 29(23):  2867-2874. 

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Based on a real intelligent factory project, this paper systematically studied the structures and implementation methods of intelligent factories, and formed an organic combination system of intelligent manufacturing and automobile manufacturing business processes in the aspects of intelligent plant design, intelligent production, intelligent logistics, intelligent management and so on. According to the research results of this paper, the intelligent manufacturing infrastructure such as digitalization plant, automatic flexible production line, logistics management system, intelligents management center were established, and the corresponding standard of intelligent factories were set up, and through the applications of industrial Internet, big data and so on, the integration of automation, informatization and digitalization in the intelligent factory system are realized, and the system framework as well as the implementation idea of an intelligent transparent automobile factory was obtained.

Processing Technology of Cylinder Liners for High-power Two-stroke Diesel Engines

ZHAO Xiangjun;TAN Yonggan;ZHOU Zhongyi;WU Kai

2018, 29(23):  2875-2881. 

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The processing route of machining the cylinder liners was discussed and the technical difficulties were analyzed, based on the analyses of structural features and application advantages of cylinder liners for 230 series high-power two-stroke diesel engines. The key technologies such as cylinder liner blank casting, brazing of cylinder liner body and water jacket, internal hole laser quenching strengthening treatment and honing of non-circular hole were studied and verified. Based on these studies, the domestic development of the 230 series cylinder liners was successfully realized. The products are put into production in lots and the application effectivenesses are very good.

Research on Twist Springback Controls of High Strength Steel Used in S-shaped Beams Based on Movable Drawbeads Overstretching Processes

WANG Chengyong;YAO Yuanyuan;CHENG Ming;AN Ziren

2018, 29(23):  2881-2886. 

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The twist springback characteristics of high strength steel S-shaped beams with variable cross-section in stamping processes were analyzed by numerical simulations and physical tests. The results indicate that the corners play an important role in twist springback. To explore the causes of the twist springback, the stress distribution and deformation of corner sections were analyzed. The forming bead was designed to balance the nonlinearity of the corners. Based on the forming bead design, the improvement effects of the two processes of variable binder force and movable drawbeads overstretching on the S-beam torsional springback were compared. The results verify that movable drawbeads are more efficient to suppress the S-beam twist springback.

Numerical Simulations of Aluminum Alloy Plates against Cube Fragment Impacts

WANG Xuan;LU Mingjian;DENG Yunfei

2018, 29(23):  2887-2894. 

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In order to study the damage characteristics and failure mechanism of different strength aluminum alloy plates impacted by cube fragments, the models of cube fragment impacting different strength aluminum alloy targets with different initial gesture were built by finite element software ABAQUS/Explicit， the effects and mechanism of initial gesture of fragments and strength of target on the ballistic characteristics were analyzed, including protective performance, failure mode and energy absorption. The results show that the ballistic limit  velocity of point contact with target is higher than that of surface contact. The ballistic limit velocity does not increase monotonically with the increase in target strength, but rather increases first and then decreases, there is an optimum strength to makes the target resistance optimal. Target strength and the initial gesture of fragment have a significant effect on the target failure mode and energy absorption, but the influence degree and mechanism of each factor are different.