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    Digital Transformation Mode and Strategy of SMEs in China
    WANG Baicun, ZHU Kailing, XUE Yuan, BAI Jie, ZANG Jiyuan, XIE Haibo, YANG Huayong,
    China Mechanical Engineering    2023, 34 (14): 1756-1763.   DOI: 10.3969/j.issn.1004-132X.2023.14.013
    Abstract585)      PDF (5220KB)(413)       Save
    Promoting the digital transformation of SMEs was of great significance for Chinas manufacturing industries to improve quality and increase efficiency. SMEs were facing problems in digital transformation, such as high cost, fuzzy path, talent shortage, and lacking analytical framework and reference paradigm for digital transformation. The key factors to achieve digital transformation were clarified by building an analytical framework for SMEs digital transformation herein. Through case studies, 4 basic path models of digital transformation of SMEs were summarized and proposed. Based on the above researches, targeted suggestions were proposed for SMEs digital transformation in China, so as to promote the digital and intelligent development of SMEs.
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    A Wafer Cycle Processing Time Prediction Method Incorporating Double Attention Mechanism and Parallel GRU
    DAI Jiabin, ZHANG Jie, WU Lihui
    China Mechanical Engineering    2023, 34 (14): 1640-1646.   DOI: 10.3969/j.issn.1004-132X.2023.14.001
    Abstract557)      PDF (4600KB)(145)       Save
    Low efficiency and low prediction accuracy were caused by the large scale of production feature data, complex correlation among features, and strong correlation of feature samples in wafer fabrication processes, so a wafer processing cycle prediction method integrating double attention mechanism and parallel GRU was proposed. Firstly, Relief-F algorithm was used to reduce the dimensionality of production feature data. Secondly, a fuzzy C-mean algorithm was used to cluster the process similarity of data samples and design a parallel GRU network to explore the strong correlation among wafer feature samples. Finally, a double attention mechanism was designed to learn the complex correlation information within key features and among features and processing cycle. The experimental results show that the proposed method may effectively reduce the prediction training time and improve the prediction accuracy.
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    Hybrid Flow Shop Scheduling Problems with Unrelated Parallel Machine Solved by Improved Adaptive Genetic Algorithm(IAGA) with ITPX
    ZHENG Kun, LIAN Zhiwei, GU Xinyan, ZHU Changjian, XU Hui, FENG Xueqing
    China Mechanical Engineering    2023, 34 (14): 1647-1658,1671.   DOI: 10.3969/j.issn.1004-132X.2023.14.002
    Abstract535)      PDF (4458KB)(102)       Save
    Aiming at the hybrid flow-shop scheduling problems, an adaptive genetic algorithm with ITPX was proposed. Firstly, the solution performance of two-points crossover(TPX) was improved by exacting point taking method. Secondly, adaptive selection probability was demonstrated based on hormonal regulation guiding convergence trend of populations. Then, a pool of high-quality chromosomes and a memory factor were established to record the high-quality chromosomes during population evolution, and two different regional crossovers were implemented. Experimentsal results show that ITPX may save optimization time and improve solution performance; the adaptive probability may enhance convergence; ITPX-IAGA may reduce solution time by more than 40% and improve solution performance.
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    Time-series Correlation Prediction of Quality in Process Production Processes Based on Deep TCN and Transfer Learning
    YIN Yanchao, SHI Chengjuan, ZOU Chaopu, LIU Xiaobao
    China Mechanical Engineering    2023, 34 (14): 1659-1671.   DOI: 10.3969/j.issn.1004-132X.2023.14.003
    Abstract511)      PDF (13154KB)(110)       Save
     To address the problems which were difficult to accurately predict production quality due to the temporal coupling of multiple processing parameters in process production, a fast and efficient production quality prediction method was proposed based on deep TCN networks and migration learning. With a sequence-to-sequence learning structure, a deep TCN and a temporal attention mechanism formed the encoding component for extracting key temporal features from multiple sources, while a residual long short term memory network formed the decoding component for simultaneous extraction of quality temporal information, and migration learning was introduced to address the adaptability of the prediction model to online production quality prediction. The experiments show that the proposed method has significant advantages in prediction accuracy and stability, and has high prediction accuracy and computational efficiency in predicting small sample data.
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    Tooth Surface Generation and Meshing Characteristics Analysis of Low-angle Face Gear Drives
    ZHOU Ruchuan, WU Wenmin, FENG Manman, GUO Hui, LIN Yanhu
    China Mechanical Engineering    2023, 34 (06): 631-640.   DOI: 10.3969/j.issn.1004-132X.2023.06.001
    Abstract479)      PDF (6100KB)(269)       Save
     Gear geometry and meshing properties of the low-angle face gear drives were investigated in order to enhance meshing capabilities of the gear drives with small shaft angle in helicopter transmission systems. The applied coordinate systems for generation of the low-angle face gear drive were established and the equation of the tooth surface of the small cone angel face gear was derived based on gear meshing theory. The tooth surface equation of a double-crowned cylindrical involute pinion was deduced by application of a generating worm.  The generated double-crowned pinion was then introduced into the low-angle face gear drive. The TCA was implemented and the influences of misalignments on the contact were researched. Stress analysis was performed for the purpose of evaluating the performance of the proposed face gear drives. And the stresses of the low-angle face gear drive were compared with the conical involute gear and cylindrical involute gear pair. The results show that the application of double-crowned pinion avoids edge contact, providing lower contact and bending stresses compared with the face-gear drive with a longitudinal modification pinion. Under the same conditions, the contact and bending stresses of the tapered face gear are 27% decrease than that of the conical involute gears. 
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    Human Factor Engineering for Human-Cyber-Physical System Collaboration in Intelligent Manufacturing
    YANG Xiaonan, FANG Haonan, LI Jianguo, XUE Qing
    China Mechanical Engineering    2023, 34 (14): 1710-1722,1740.   DOI: 10.3969/j.issn.1004-132X.2023.14.008
    Abstract469)      PDF (5740KB)(237)       Save
    The theoretical system of intelligent manufacturing for HCPS confirmed the central position of human in the intelligent manufacturing system. Starting from the demand of human-machine collaboration in the intelligent manufacturing system, the emphases of human factors in HCIM were discussed from three levels such as behavior, intention, and cognition, based on the theory of gulf. Focusing on virtual-real fusion scenarios, multimodal human-machine interaction, cognitive quantification and other methods, the importance of human factor engineering in promoting the integration of human-computer intelligence was expounded. Finally, research direction and development suggestions of human-centered intelligent manufacturing from the implementation of HCPS intelligent manufacturing systems were put forward.
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    Numerical Simulation and Experimental Verification of Pulling-riveting Process of New Non-plate Nuts
    WANG Shoucai, SUN Ang, LIU Rugang
    China Mechanical Engineering    2023, 34 (07): 875-881.   DOI: 10.3969/j.issn.1004-132X.2023.07.014
    Abstract456)      PDF (7273KB)(78)       Save
    Due to the excellent characteristics in improving installation efficiency and reducing fatigue sources, a new type of 304 stainless steel non-plate nut was generalized in aviation field. Based on Johnson-Cook model, the finite element model was built to analyze the pulling-riveting progress. The loading-curve, plastic-flow, clamping force and interference amount, and the influences of interlayer state on riveting quality were analyzed. Meanwhile, the riveting installation tests of nuts were carried out. Results show that the finite element simulation model is in good agreement with the test loading curve, and the maximum load deviation from test is as 2.4%. When the compression stress of the nut is much higher than the yield stress of the material, the instability of the structure occurs, and the bulge structure is formed rapidly. The plastic flow mainly develops along the radial direction. The pulling-riveting process may provide a certain amount of clamping force and interference to interlayer. The clamping force reaches the maximum value after complete riveting, yet in a certain range, the slope of the riveting interlayer does not affect the clamping force. The maximum interference in the riveting processes is about 4.6%.
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    Robot Welding Trajectory Planning and High Frequency Control for Curved Seams
    WU Chaoqun, ZHAO Song, LEI Ting
    China Mechanical Engineering    2023, 34 (14): 1723-1728.   DOI: 10.3969/j.issn.1004-132X.2023.14.009
    Abstract440)      PDF (6070KB)(217)       Save
    In a robotic real-time seam tracking system, the trajectory planning and control delay affected the tracking accuracy and welding quality. To solve this problem, a piecewise real-time trajectory planning and control method for curved seams was proposed by combining B-spline curve interpolation algorithm and EGM module. Firstly, the trajectory was segmented according to the principle of optimal interpolation time. Secondly, three times non-uniform B-spline was used to interpolate each trajectory to obtain the interpolation points. Finally, the high-frequency controller of the robot was designed. The interpolation points were sent to the robot by EGM module in a cycle of 4 ms to guide the robot movements. The experimental results show that this method may complete the planning of sine curve weld and guide the robot welding in 100 ms, and the tracking errors were controlled within ±0.2 mm, which realizes the rapid trajectory planning and high-frequency control.
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    Fault Diagnosis Method of Rolling Bearings Based on Simulation Data Drive and Domain Adaptation
    DONG Shaojiang, ZHU Peng, ZHU Sunke, LIU Lanhui, XING Bin, HU Xiaolin
    China Mechanical Engineering    2023, 34 (06): 694-702.   DOI: 10.3969/j.issn.1004-132X.2023.06.008
    Abstract428)      PDF (6394KB)(265)       Save
    To solve the problem that it was difficult to obtain a large number of high-quality rolling bearing fault data in the actual industrial environment, and the generalization performance of the intelligent diagnosis model was poor, a fault diagnosis method was proposed based on simulation data driven and domain adaptation. Firstly, a physical model was established to obtain rich simulation data, which simulated different failure forms of bearings according to bearing parameters and corresponding operating conditions. Secondly, the transfer learning method was used to solve the problem of inconsistent data feature distributions between simulation and actual fault data. The residual channel attention mechanism network was used to extract the transfer fault features of different domains, and the adaptive operation of different domains in the network training processes was carried out through the condition maximum mean discrepancy metric criterion, which taken into account the conditional distribution discrepancies between different domains. Finally, different transfer model tests were carried out on the bearing data sets damaged by man-made damage and accelerated life test. The results show that the method proposed may obtain better recognition accuracy when the target domain contains a small number of labels. 
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    A Robotic Multi-directional Polishing Trajectory Generation Method Based on Preston-PSO Algorithm
    LI Jiaxuan, LI Lun, ZHOU Bo, ZHAO Jibin, ZHU Guang, WANG Zhengjia,
    China Mechanical Engineering    2023, 34 (14): 1729-1740.   DOI: 10.3969/j.issn.1004-132X.2023.14.010
    Abstract414)      PDF (13506KB)(128)       Save
    Aiming at the texture phenomenon in robotic polishing processes, a multi-directional trajectory generation method used for robotic polishing was proposed based on Preston equation and particle swarm optimization algorithm,and the generated multidirectional polishing path was smooth, evenly distributed and without corners. Simulations and experiments show that compared with the polishing effectiveness of parallel trajectory, the trajectory generated by this algorithm may effectively inhibit the generation of surface polishing texture, reduce the roughness of polished surfaces, improve the surface quality, and obtain good mirror polishing effectiveness.
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    Simulation and Experimental Study of Magnetic Field-assisted Shear Thickening Fluid Polishing for Cemented Carbide Blades
    LI Hongyu, HUANG Xiangming, MING Yang, LI Xiyang, ZENG Qing, ZHOU Dongdong
    China Mechanical Engineering    2023, 34 (06): 650-659.   DOI: 10.3969/j.issn.1004-132X.2023.06.003
    Abstract409)      PDF (14414KB)(180)       Save
    In order to improve the surface quality of ground cemented carbide blades, a new method for polishing cemented carbide blades, magnetic field-assisted shear thickening fluid polishing, was proposed. The basic principles of the polishing method were introduced, the polishing liquid was prepared, and the rheological properties were tested and analyzed. Based on the rheological test results, the optimal preparation scheme of the polishing liquid was obtained. The flow field state of the workpiece surface under different placement methods was obtained by the ANSYS FLUENT module, and the distribution of dynamic pressure and shear stress on the workpiece surfaces was analyzed under different polishing speeds and magnetic induction strengths, and the placement mode and processing parameters of the workpiece were determined. A polishing experimental platform was established, and the effects of polishing speed, magnetic induction intensity and other processing parameters on the surface roughness and material removal rate were explored. The experimental results show that the surface roughness Ra decreases with the increasing polishing speed, but it is not significantly affected by the magnetic induction intensity. And the product of the shear stress and velocity of the polishing liquid on the workpiece surfaces has a positive correlation with the material removal rate. By optimizing the polishing processing parameters(The workpiece is placed vertically, the polishing speed is as 100 r/min, and the magnetic induction intensity is as 30 mT), the ultra-precision machined surfaces with surface roughness Ra=15 nm and the high material removal rate(11.1 μm/h) may be obtained. 
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    Evolution of Concept of Machine Composition from the 19th Century to Modern Time
    ZHANG Ce, YANG Tingli, LIU Jianqin
    China Mechanical Engineering    2023, 34 (10): 1135-1139.   DOI: 10.3969/j.issn.1004-132X.2023.10.001
    Abstract384)      PDF (2405KB)(397)       Save
     With increasing of productivity and development of machines, the concept of “machine composition” also evolved. The requirements of modern society for machines were gradually increasing, and complex machines came from the transformation of traditional machines. Understanding the evolution of machines was a necessary process for the transformation of traditional machines. Marx first described the composition of machines in his Das Kapital, which coincided with the start of the Second Industrial Revolution. However, within only a few years, the control system joined a machine, and Marxs “concept of machine composition” began to be broken through. In the second half of the 20th century, in the Third Scientific and Technological Revolution, the concept of mechatronics emerged, and electronic technology, control technology and sensor technology were integrated into mechanical systems. The evolution processes of the concept of machine composition were explained through the history of the development of machines herein. By analyzing the evolution of the concept of machine composition, a more accurate definition of modern mechanical systems was put forword. It may enlighten people, increase their understanding of the machine itself, which has guiding significance for modern mechanical product designers. 
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    Job-shop Scheduling Problems Considering Similar Learning Effect in One-worker and Multiple-machine Partterns
    ZHANG Weicun, GU Hongyu
    China Mechanical Engineering    2023, 34 (14): 1701-1709.   DOI: 10.3969/j.issn.1004-132X.2023.14.007
    Abstract371)      PDF (4248KB)(129)       Save
     A multi-objective job shop scheduling model was established considering the effects of job similarity and personnel learning under the one-worker multiple-machine production mode, and a grid filtering external archive genetic algorithm(GFEAGA) was designed to solve the scheduling problems. In order to improve solution efficiency, a two-stage coding and decoding approach was adopted, and an improved N6 neighbor structure search method was applied. The personnel selection method was designed to balance personnel workload. Non-dominant individuals were filtered based on grid sorting to enhance the diversity of the solution sets. The experiments verified the high efficiency and superiority of GFEAGA solution, and the sensitivity of the similarity and learning rate in the model were analyzed.
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    Analysis and Comparison of Kinematic Characteristics for Two Typical 6-DOF Suspension Mechanisms at High Angles of Attack
    CHEN Hengtong, WANG Xiaoguang, JIANG Hailong, LIN Qi
    China Mechanical Engineering    2023, 34 (06): 641-649.   DOI: 10.3969/j.issn.1004-132X.2023.06.002
    Abstract360)      PDF (8317KB)(141)       Save
     To meet the requirements of multi-DOF (degree of freedom) coupled motion for the aircraft model, it was urgent to develop new suspension technologies. The motion characteristics of two typical six-DOF rigid and flexible parallel suspension mechanisms at high angles of attack were investigated. Firstly, a transverse 6-PUS rigid parallel suspension mechanism was designed, and the aircraft models pose workspace was solved based on the geometric and kinematic restraints. The mechanism stiffness matrix was also derived. As to the wire-driven parallel suspension mechanism, a symmetrical configuration with 8 wires was proposed and the dynamic motion workspace was obtained. By analyzing and comparing the workspace and internal frequencies of the two mechanisms, it is known that both of the rigid and flexible suspension methods may achieve large scale 6-DOF motion, but wire-driven parallel suspension system (WDPSS) has a larger workspace in the transverse and pitch motions with high natural frequency. Finally, the feasibility and effectiveness of WDPSS is experimentally validated through an example of pitch motions at high angle of attack. 
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    Online Diagnostic Inspection and Prediction of Product Quality in Injection Molding Intelligent Factories Based on Data Mining
    CHEN Yu, XIANG Wei, GONG Chuan
    China Mechanical Engineering    2023, 34 (14): 1749-1755.   DOI: 10.3969/j.issn.1004-132X.2023.14.012
    Abstract349)      PDF (1793KB)(125)       Save
    The dimensional accuracy of injection products was related to the injection processing parameters, and the real-time conditions of each stage in the injection processes and the changes of real-time working conditions. A workpiece quality diagnosis model was developed herein based on data mining. The real-time data collected by high-frequency sensors such as temperature, pressure, and displacement etc. in mold were used to construct the high-dimensional time series feature set. A three-stage feature selection method was used to determine the key feature subset, which was used to train the online quality detection model based on LightGBM classifier. The future values of each features were predicted based on the CNN-LSTM temporal prediction model, and the product quality was forecasted in advance with the classifier. The results show that the average recall rate of the macros is as 89.1%, and the average recall rate of the macros is as 81.6%.
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    Surface Morphology Characteristics and Effectiveness Analysis of Ultrasonic Longitudinal Torsion Assisted Milling of Titanium Alloys
    LI Fengqin, ZHAO Bo, HAO Wangshen, WANG Xiaobo
    China Mechanical Engineering    2023, 34 (06): 677-684,693.   DOI: 10.3969/j.issn.1004-132X.2023.06.006
    Abstract338)      PDF (10524KB)(107)       Save
     In order to solve the problems that the surface quality of difficult-to-cut titanium alloy materials was difficult to be controlled in milling,  a combination of ultrasonic longitudinal-torsional vibration and milling was proposed, and the experimental platform of ultrasonic longitudinal-torsional milling system was built. A single factor test was carried out from four aspects of cutting speed, feed per tooth, cutting depth, and ultrasonic amplitude, and the surface textures and roughnesses of ultrasonic longitudinal-torsional milling and ordinary milling were compared and analyzed. It is found that the surface textures produced by ultrasonic longitudinal-torsional milling were uniform, while the common milling has obvious adhesion phenomena accompanied by scale-spikes. The surface roughness values of ultrasonic longitudinal-torsional milling are obviously lower than that of ordinary milling, and it is concluded that the higher the speed, the larger the amplitude and the smaller the surface roughness value during ultrasonic longitudinal-torsional milling. The simulation and experiments were contrasted and effectively analysed for the feed per tooth, which has a great influence on the surface topography. The results show that the trends of experiment and simulation are consistent and have a high degree of agreement with the theoretical analysis, and the relative errors of ultrasonic longitudinal-torsional milling are lower than that of ordinary milling, and the quality of ultrasonic surface milling is obviously higher than that of ordinary milling. 
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    Calibration Parameter Optimization and Accuracy Evaluation of Complex Visual Measurement Systems
    SUN Jiale, LUO Chen, ZHOU Yijun, WANG Wei, ZHANG Gang
    China Mechanical Engineering    2023, 34 (14): 1741-1748,1755.   DOI: 10.3969/j.issn.1004-132X.2023.14.011
    Abstract338)      PDF (3739KB)(89)       Save
    There were many calibration errors in complex visual measurement systems, and the coupling between errors directly affected the accuracy of system measurement, so the accuracy improvelment of system calibration parameters was the key to ensure the system measurement accuracy. Thus, a calibration parameter optimization method was proposed based on multi-dimensional angular point error compensation. Firstly, a multi-dimensional angular point error function was defined, and the corresponding optimization model whose parameters were solved by LM algorithm was established. Then, the effects of the parameter optimization method on the system calibration optimization were evaluated by the optimization rate of the system calibration errors. Experimental results show that the optimization rate of the system calibration errors may reach 48%, the system measurement accuracy is high and meets the measurement requirements. 
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    Supply Chain Inventory System Optimization Model under Demand Disturbances
    WU Yingnian, ZHANG Jing, LI Qingkui, JIAO Shuai,
    China Mechanical Engineering    2023, 34 (14): 1672-1682,1700.   DOI: 10.3969/j.issn.1004-132X.2023.14.004
    Abstract329)      PDF (7177KB)(65)       Save
     Aiming at the supply chain inventory systems under demand disturbances, a supply chain inventory system optimization model was designed combining improved sliding mode controller and disturbance observer. A dynamic inventory model of a three-echelon networked supply chain system was established based on the product operation logic of the supply chain system. An optimization model combining improved sliding mode controller was designed based on adaptive exponential reaching law and disturbance observer. The model could suppress the influences of demand disturbances on the supply chain inventory system under the premise of ensuring system stability. Simulation comparison experiments verified the effectiveness of the optimization model.
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    Finite Element Analysis for Extrusion, Assembly and Loosening Processes of Hi-lock Nuts
    ZHANG Jingdong, DENG BoGUI Xuewen, LI Jian, LIAO Ridong
    China Mechanical Engineering    2023, 34 (12): 1387-1394,1406.   DOI: 10.3969/j.issn.1004-132X.2023.12.001
    Abstract304)      PDF (12625KB)(256)       Save
     The FE(finite element) modeling method of UNJ threaded hi-lock nuts was investigated, and a modeling program was written to generate structured meshes, through which the fine FE meshed model was established. The extrusion process, assembly process and loosening behavior under transverse loads of hi-lock nuts were simulated by finite element method(FEM), and the simulated locking torque was verified by tightening tests. The simulation results show that within a certain range, the maximum radial displacement and the locking torque of the hi-lock nuts are linearly related to the extrusion amount approximately. With the extrusion amount increases, the maximum radial displacement and the locking torque both increase. The higher the locking torque of the hi-lock nuts, the better the anti-loosening performance. However, there is an optimal value of the extrusion amount for the anti-loosening performance. Once the extrusion amount exceeds the optimum value, increasing the amount of extrusion does not have a significant effect on the improvement of the anti-loosening performance.
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    Energy Regeneration Assistance of Soft Braking and Corresponding Thermal Dissipation Management System
    ZHOU Xin, LEI Xianqing, LI Geqiang
    China Mechanical Engineering    2023, 34 (06): 746-755.   DOI: 10.3969/j.issn.1004-132X.2023.06.014
    Abstract302)      PDF (12027KB)(104)       Save
    In order to improve the power performance and the management level of hydraulic system temperature, the hydraulic system design was optimized for mine wide-body truck. This improved hydraulic system was installed in one mine wide-body truck which was used to do a full load transfer comparison test with a mine wide-body truck that was of the same model but enhanced with the engine capacity. At the same time, a physical model was established with AMESim and AVL Cruise to simulate dynamic properties of each module and power performance of the whole mine wide-body truck of the hydraulic system under normal working circumstances. The simulation and testing results show that the system may achieve soft braking during heavy load downhill transportation. The energy regeneration module may improve the power performance index as same as the mine wide-body truck which utilized larger displacement engine, and reduce the combined fuel consumption by about 17%. The energy regeneration module may effectively absorb wheel edge impacts and instantaneous pressure impacts caused by hydraulic system module switching. The thermal management module of the hydraulic system may make the mine wide-body truck working under ambient temperatures ranging from -5 ℃ to 45 ℃, and keep the thermal equilibrium temperature of the system at 70±5 ℃. Meanwhile, carriage auxiliary heating employed in extreme cold weather may improve the lighter efficiency as well as the energy utilization of the hydraulic system by 19%.
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    Research Progresses of Finishing Technology for Inner Channel of Additive Manufacturing Parts
    WANG Lei, WU Yuliang, ZHAO Jiyuan, LU Bingheng,
    China Mechanical Engineering    2023, 34 (07): 757-769.   DOI: 10.3969/j.issn.1004-132X.2023.07.001
    Abstract299)      PDF (17271KB)(324)       Save
    In the field of aerospace, metal additive manufacturing technology had broad application prospects in the formation of parts with complex inner channels. However, the finishing of additive manufacturing parts with complex inner channels was a bottleneck problem in industrial applications. The principle, technology and development of mechanical polishing, chemical and electrochemical polishing and electrolyte plasma polishing on inner channel were reviewed herein. In addition, the adaptability and exploration direction of mechanical polishing, chemical and electrochemical polishing and electrolyte plasma polishing for the finishing of inner channel of additive manufacturing parts were studied respectively. Finally, the development trend of the key technologies for the finishing of inner channel of additive manufacturing parts was put forward: ①the finishing technology research of the inner channel of the additive parts for functionally graded materials and polymetallic materials; ②the research on compound finishing technology for complex inner channel with complex geometry, bifurcation, gradual capillary structure, topology and so on; ③the research on high-precision detection method for the finishing quality of inner channel and the three-dimensional reconstruction technology of geometric errors.
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    Study on Modeling of Material Removal Depth for Blisk Polishing by ABFW Based on Hertz Contact Theory
    ZHANG Junfeng, WU Xiaojun, SHI Yaoyao, LIN Xiaojun
    China Mechanical Engineering    2023, 34 (06): 668-676.   DOI: 10.3969/j.issn.1004-132X.2023.06.005
    Abstract294)      PDF (5074KB)(196)       Save
    To investigate the material removal mechanism in complex curved surface polishing with ABFW, it was assumed that the distribution of abrasive grain protrusion heights was normal distribution. The distribution model of polishing pressure between ABFW and blade was obtained based on Hertz contact theory. The force analysis of a single abrasive grain was carried out based on the elastic-plastic contact theory, and then the cutting depth model of the abrasive grain was established combined the height distribution function. Thus, the material removal volume of single abrasive grain was determined by synthesizing the spindle speed, feed speed and the shape of abrasive grain cutting groove, and the material removal depth model was established by integrating along the polishing trajectory. The experimental results show that the maximum deviation and average deviation between the predicted values and the experimental ones of material removal depth are 4.85% and 2.95%, respectively, which verifies the correctness and effectiveness of the established model. 
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    Deformation Law Model and Simulation Verification of Pod Structures with Large Exhibition-to-receive Ratio for Aerospace Applications
    YANG Shuo, ZHANG Jie, KONG Ning, WANG Haowei, WANG Xiaoyu, ZHUANG Yuan
    China Mechanical Engineering    2023, 34 (07): 780-788.   DOI: 10.3969/j.issn.1004-132X.2023.07.003
    Abstract294)      PDF (4964KB)(214)       Save
    The pod rod, also named as CTM(collapsible tubular mast), was an elastic stretching structure with large exhibition-to-receive ratio. It might be compressed into a plate and loaded on the spacecraft and self-deployed into a hollow cylinder when needed, which might be used to expand solar wings, satellite antennas and other components, and might reduce the volume of spacecraft during launch. The mechanics properties of pod structure should be considered when designing the structure size. A numerical model was established by means of mechanics analysis in order to solve the problems of large amount of calculation, and frequent variation of the factors that affecting mechanics properties. The numerical model might be applied to calculate the compressive force variation during the entire compression processes for the pod structure with different size parameters. The finite element analysis software ABAQUS was used to simulate and analyze the compression deformation. The deviations between the calculation results and the simulation ones are less than 10%. The influences of size parameters of the pod structure on the compressive force were obtained through numerical model analyses.
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    Control Strategies for Industrial Robot Motion along Slot Based on Force and Position Hybrid Guidances
    ZHANG Junxin, CHEN Wei, HUANG Sikai, WU Haibin
    China Mechanical Engineering    2023, 34 (06): 712-719,726.   DOI: 10.3969/j.issn.1004-132X.2023.06.010
    Abstract290)      PDF (5629KB)(169)       Save
     Aiming at the problems of the robot motion  along slot  was constrained by the combination of multi-directional positions and forces, a force and position hybrid guidance strategy was proposed, and an ADRC was designed based on the impedance model to optimize the force control loop of the strategy. Then, the ADRC was improved based on the double fuzzy structure, and a switching variable universe fuzzy ADRC was obtained, so as to enhance the adaptability of the industrial robots to the unknown environment in the hybrid control of force and position. Finally, the performance of the proposed algorithm was simulated, and the experiments were carried out by taking the parallel slot assembly of mobile phone RF(radio frequency) line as an example. Simulation and experimental results show that compared with the general control method, the proposed control strategy has better force and position hybrid control performance, and may be better applied to the along slot motion of industrial robots.
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    Performance Improvement of Flexible Pressure Sensors by Dual-level Microstructure
    ZHOU Danyan, HUANG Hanxiong, LUO Duyu
    China Mechanical Engineering    2023, 34 (06): 720-726.   DOI: 10.3969/j.issn.1004-132X.2023.06.011
    Abstract288)      PDF (5109KB)(212)       Save
    The flexible thermoplastic polyurethane sheets with the single- and dual-level microcolumn arrays were rapidly prepared by using injection-compression molding with two different template design schemes. The microstructured flexible sensing substrates were obtained after cutting the sheets and spraying gold layer on them. The flexible pressure sensors were prepared by assembling the sensing substrates with the single-/dual-level microcolumns and the flat sensing substrate face-to-face, which were denoted as sensor 1 and sensor 2, respectively. The simulated results show that higher contact stress appeares around the edges on the top surfaces of the microcolumns under pressure. The longitudinal sections of the single- and dual-level microcolumns under pressure exhibit  “bowl” and “bud” geometries, respectively. The dual-level microcolumn can be deformed under lower pressure, and the contact deformation and contact area with the flat sensing substrate under pressure are larger. Therefore, compared to sensor 1, sensor 2 exhibits a higher sensitivity(0.53 kPa-1,0~1 kPa), shorter response time/relaxation time(100 ms/80 ms), lower detection limit(about 58 Pa). Sensor 2 has a wide detection range(0.058~600 kPa)and maintaines a relatively stable piezoresistive response in 4000 cycles of compression/release tests(under a peak pressure of about 500 kPa), which is ascribed to higher pressure resistance of the microcolumn. Sensor 2 may accurately detect human pulse, vocalisation and movement, demonstrating its potential for smart wearable applications. 
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    Mechanism and Influencing Factors of Shape Warpage of TA2/Q235B Composite Plates during Stress Relief Annealing
    WANG Rui, ZHAO Zhimin, HUANG Jing, LIU Xin, JI Xiangyun, SU Chunjian
    China Mechanical Engineering    2023, 34 (10): 1230-1240.   DOI: 10.3969/j.issn.1004-132X.2023.10.013
    Abstract288)      PDF (11513KB)(66)       Save
    In order to explore the mechanism and influencing factors of shape warping during stress relief annealing of TA2/Q235B composite plates, a Gleeble thermal simulation experiment was carried out to obtain the true stress and strain of TA2 and Q235B materials under different working conditions. The JC constitutive model parameters of TA2 and Q235B were determined by numerical method, and the finite element simulation model of stress relief annealing was established by combining boundary conditions such as temperature and external load. The heat treatment experiments verified the accuracy of the model. The results show that a certain tensile load may improve the strain distribution, excessive tensile load results in local concentration of residual strain, and the composite ratio and the total thickness affect the stress distribution, which will affect the strain states. 
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    Failure Mechanism on Touchdown Bearings of Heavy Maglev Rotor Drop
    LI Zilin, SHI Zhengang, TIE Xiaoyan, YANG Guojun, REN Wenliang, YAO Jiakang, WANG Yuming, WANG Zixi
    China Mechanical Engineering    2023, 34 (09): 1009-1018.   DOI: 10.3969/j.issn.1004-132X.2023.09.001
    Abstract285)      PDF (11267KB)(129)       Save
    For the national key R&D program “high-speed precision suspension bearing”, the requirements for the drop capacity of TDBs were: rotor mass ≥3000 kg, drop speed ≥3000 r/min, and successful drops ≥10 times. Based on this, the research and development of TDBs drop failure mechanism were carried out. Two hybrid TDBs with ceramic balls suitable for drop conditions were proposed: full complement ball without cage scheme and non-full complement ball with cage scheme. A rotor drop simulation model was built including dynamics and thermal. The force and heating processes of the drop processes were simulated. The effectiveness of the simulation model was verified by mounting the TDBs in the test bench for experiments. TDBs without cage are found to have failed severely. The damages of the failed bearing are detected, and it is observed that due to the large friction coefficient between the rolling elements, the rolling elements are seized up, resulting in continuous dry friction between the rolling elements and the raceways, and between the inner ring and the rotor, and serious burns and wear of the inner rings.
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    Design of Deep-sea Non-contact Magnetic Drive Sediment Penetration Measurement Devices Based on Jiaolong Manned Submersible
    REN Yugang, LIU Yanjun, DING Zhongjun
    China Mechanical Engineering    2023, 34 (06): 739-745.   DOI: 10.3969/j.issn.1004-132X.2023.06.013
    Abstract283)      PDF (8062KB)(86)       Save
     Sediment penetration test was an important in-situ testing technique for deep-sea sediment strength. In view of the extreme environmental characteristics of the 7000 meter deep sea and the scientific demands for fine in-situ measurement, a deep-sea non-contact strong magnetic sediment penetration strength in-situ measurement device was developed based on the Jiaolong manned submersible, which broke through the problem that the original penetration measurement techniques in the 7000 meter deep sea structure was complex and could not achieve in-situ and fine measurement, A new method of solving deep-sea pressure resistance and strain gauge deformation conduction was proposed based on the non-contact principle of permanent magnetic force balance conduction of manned submersible. The prototype development and deep-sea sea tests were completed, and good test results were obtained. The whole system adopted self-contained working mode to collect and store data, and might be connected with the computer to realize in-situ data reading. The operating water depth is as 7000 m, the maximum penetration depth is as 250 mm, the measuring range is as 0~100 kPa, and the accuracy may reach 5%~10% FS(full scale). In March 2021, the Jiaolong manned submersible completed 5200 m and 6650 m sea trials in 181 and 185 dives in the Parihivila basin, and successfully obtained geotechnical data. 
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    Rotating Eddy Current Testing for Inspection of Cracks at Hole Edge
    ZHU Yulong, ZHAO Yingsong, FANG Yang, CHEN Hongen, CHEN Zhenmao,
    China Mechanical Engineering    2023, 34 (08): 883-891.   DOI: 10.3969/j.issn.1004-132X.2023.08.001
    Abstract283)      PDF (6432KB)(240)       Save
     Rotating eddy current testing method was applied for reliable ECT of cracks at the cooling hole edge of gas turbine blades. At first, a numerical simulation scheme and code were developed, and numerical results show that the method might find cracks by amplitude modulated rotating ECT. A rotation ECT probe and a inspecting system were designed to inspect test-pieces with cooling holes and cracks at their edges. The consistency of experimental ones and simulation results show that the proposed numerical simulation scheme and rotating ECT are effective for detecting the hole edge cracks. 
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    Multichannel Information Fusion and Deep Transfer Learning for Rotating Machinery Fault Diagnosis
    ZHANG Long, HU Yanqing, ZHAO Lijuan, ZHANG Hao
    China Mechanical Engineering    2023, 34 (08): 966-975.   DOI: 10.3969/j.issn.1004-132X.2023.08.011
    Abstract282)      PDF (9432KB)(154)       Save
    To address the problems of inadequate information on the characteristics of single channel signals, a rotating machinery fault diagnosis method of multichannel information fusion and deep transfer learning approach was proposed. Firstly, the one-dimensional signals collected by multi-sensors were used to generate separate time-frequency maps by wavelet transforms. Then, the information of the maps was fused into multi-channel images. Finally, the pre-trained deep residual network, as a transfer model, was used for fault diagnosis of the rotating machinery. The identification accuracy of the tests on the cylindrical roller bearing, locomotive bearing, and gearbox datasets of a bureau of locomotive section is as 99.23%, 99.78%, and 99.50% respectively; and the identification accuracy of the cross-service transfer tests on the Case Western Reserve University bearing dataset is as 93.12%, which indicates the superiority and scalability of the proposed method.
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    Ultrasonic TFM Inspection and Quantitative Method of Defects for Curved Surface Structures of Aeroengine Casing Rings
    GUAN Shanyue, WANG Xiaokai, HUA Lin, LI Yixuan,
    China Mechanical Engineering    2023, 34 (08): 892-898.   DOI: 10.3969/j.issn.1004-132X.2023.08.002
    Abstract278)      PDF (9571KB)(153)       Save
    Grooves and round corners of ring forgings used in aeroengine casing were prone to produce various defects. Taking the curved surface structures of aeroengine casing rings as an object, the ultrasonic TFM detection and defect quantification were proposed. The testing areas were divided into grid points in cylindrical coordinate system and the reference blocks with 0.8 mm artificial defects were designed. The maximum amplitude defect data set at all grid points was collected. The data set was fitted in two directions of depth and angle, and the distance angle amplitude surface defects quantitative evaluation method was established. The experimental results of a casing ring specimen show that the errors of quantitative method are less than 1 dB. 
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    Efficient Optimization Design Method of Centrifugal Impellers Based on Multi-surrogate Model
    LIU Jisheng, JI Liang, LI Wei, JIA Zhixin, CHENG Jinxin, FANG Pengcheng
    China Mechanical Engineering    2023, 34 (08): 899-907.   DOI: 10.3969/j.issn.1004-132X.2023.08.003
    Abstract278)      PDF (8420KB)(147)       Save
    Aiming at the problems of excessive number of iterations and time consumption in automatic optimization design, an efficient optimization search model for centrifugal compressor blades was established based on multi-surrogate model optimization algorithm. A global/local model management strategy and a sample filling method were studied. The comprehensive performance of multi-surrogate model and common meta-heuristic optimization algorithms(particle swarm algorithm, multi-island genetic algorithm, etc. )were compared and analyzed, and the effectiveness of the efficient optimization search model was verified. The results of the centrifugal impeller optimization show that the isentropic efficiency is improved by 0.73%, the total pressure ratio is increased by 0.18%, and the surge margin is improved by 1.1%. Compared with the classical particle swarm algorithm, the optimization time may be reduced by 54.9%. 
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    Patent Data Driven Product Innovation Design Based on SAO
    LIN Wenguang, LIU Xiaodong, XIAO Renbin
    China Mechanical Engineering    2023, 34 (15): 1765-1777.   DOI: 10.3969/j.issn.1004-132X.2023.15.001
    Abstract278)      PDF (5241KB)(265)       Save
    The patent data-driven product innovation design method was proposed based on SAO using big data mining technology. Firstly, semantic dependency parsing was used to mine the SAO structure and interaction relationships among product components from patent text databases. Subsequently, a complex network knowledge model was constructed for product systems, and the constraint coefficients of components in the complex network were calculated by using structural hole theory to identify the innovative target components. Then, the semantic similarity coefficients of components were calculated using Word2Vec, and the functional similarity coefficients were calculated using SAO similarity algorithm. And the recommendation algorithm and combination matrix were integrated to achieve structural innovation, functional innovation, and functional optimization. Finally, a typical bathroom shower product was taken as an example to demonstrate the method in detail, which fully verifies the effectiveness and progressiveness of the method. 
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    Multi Tooth Meshing Characteristics and Load Bearing Contact Analysis Method of Cycloidal-pin Wheels
    WANG Yongqiang, WEI Bingyang, XU Jiake, YANG Jianjun
    China Mechanical Engineering    2023, 34 (10): 1151-1158.   DOI: 10.3969/j.issn.1004-132X.2023.10.003
    Abstract271)      PDF (4467KB)(218)       Save
     The tooth profile equations of cycloidal gear were derived by the envelope methods, and the tooth surface contact parameters were obtained. An accurate algorithm for the geometry analysis of the backlash was proposed, which solved the defects that the traditional backlash algorithm might only be used for the constant displacement modification. The tooth by tooth clearance elimination methods were used to solve the deformation compatibility equation, which avoided the error and uncertainty of conventional meshing analysis and improved the calculation accuracy and efficiency of load-bearing contact analysis. The complete calculation flow from tooth surface contact analysis to load contact analysis was given, and the accurate load parameters of any angle position and different modification methods were obtained. 
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    Molecular Dynamics Simulation for Effect of Nanoparticle Additives on Boundary Lubrication
    PAN Ling, LIN Guobin, HAN Yuqing, YU Hui
    China Mechanical Engineering    2023, 34 (10): 1140-1156.   DOI: 10.3969/j.issn.1004-132X.2023.10.002
    Abstract267)      PDF (12614KB)(172)       Save
    The boundary lubrication behavior of Cu nanoparticles in n-hexadecane was investigated under different loads by experiments and simulations herein. Boundary lubrication model with sinusoidal rough peaks was established. The density distribution of the lubricant along the film thickness with and without Cu nanoparticles were simulated at different loads using MD respectively. The shear velocity in the opposite direction was applied to the upper and lower solid walls of the system, and the stress between the wall atoms and the copper particle atoms, the friction force of the solid-liquid interface, the normal pressure and the friction coefficient were calculated. The friction coefficient of the lubricant containing nano-copper particles was measured with a micro-nano scratch meter. The results show that the base oil n-hexadecane in the two lubrication systems is stratified under different pressures. There are still a small amount of n-hexadecane molecules at the contact interface when the nano-rough peaks are directly contacted, and the arrangement direction of the molecular main chain is the same as the shear direction. Cu nanoparticles may reduce the maximum stress of solid wall by 35.3% and improve the bearing capacity of lubrication system at 200 MPa. The lubricating oil film of lubrication system without Cu nanoparticles breaks at 50 MPa, while that of lubrication system with Cu nanoparticles breaks at 200 MPa. The friction coefficient of two lubrication system under boundary lubrication is simulated, which is in accordance with the experimental measurement. 
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    Analysis and Experimental Verification of Corner Filling Degree of Rectangular Tube Roll Forming
    XING Menglong, DU Fengshan, FU Yutao
    China Mechanical Engineering    2023, 34 (07): 866-874.   DOI: 10.3969/j.issn.1004-132X.2023.07.013
    Abstract263)      PDF (11323KB)(57)       Save
    In order to improve the forming accuracy of square rectangular tube corners formed by roller forming, the causes of underfilling rectangular tube corners were analyzed according to the law of constant volume and the principle of equal metal flow per second. The finite element model of roll forming was established according to the actual production parameters in the factories, and the influences of pipe diameter and wall thickness on the thickening coefficient and corner filling degree in the forming processes were analyzed. According to the linear relation of arc length of neutral layer in underfilled regions of the corner, the tube diameter was corrected and the coefficient correction relation was determined. The damage of the corner forming processes was judged, and the appropriate diameter of the round pipe was selected. The simulation results were compared with the experimental ones. The results show that the corners are underfilled with the increase of wall thickness during roll forming. The decrease of wall thickness leads to the decrease of thickening coefficient, and the required diameters of circular pipes are smaller. With the increase of pipe diameters, the corner filling degree is better, at the same time, the increase of pipe diameters will increase the possibility of damage in the inner corner at the exit of roll forming. The errors between the test results and the experimental results are small, which verifies the accuracy of the simulation model. 
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    Research on Underwater Gliders Path Tracking Based on Reinforcement Learning Algorithm
    SHI Qingqing, ZHANG Runfeng, ZHANG Lianhong, , LAN Shiquan,
    China Mechanical Engineering    2023, 34 (09): 1100-1110.   DOI: 10.3969/j.issn.1004-132X.2023.09.011
    Abstract261)      PDF (6340KB)(247)       Save
    Aiming at the large deviations between the actual paths and the predetermined ones of underwater gliders affected by ocean current, a neural network ocean current prediction model with long-term and short-term memory and attention mechanism was established based on the traditional long-term and short-term memory network model.The dynamic Q-table of underwater glider motions was generated by depth neural network, and the optimal motion attitude was selected by reinforcement learning algorithm. Considering the influences of ocean current, an underwater glider path tracking algorithm was constructed based on depth reinforcement learning. The results show that the long-term and short-term memory network based on attention mechanism has less mean square errors and root mean square errors in ocean current prediction than that of the traditional integrated moving average autoregressive model and long-term and short-term memory network.Compared with the traditional PID control, the deep reinforcement learning model may reduce the root mean square errors of the underwater glider trajectory by 50.9%, and significantly improve the path tracking accuracy.
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    Clustering of Component Assembly Units with Hierarchical Branching for Trunks of Tree Structures
    CHENG Bin, ZHANG Songsong, WANG Xiaoming
    China Mechanical Engineering    2023, 34 (06): 703-711.   DOI: 10.3969/j.issn.1004-132X.2023.06.009
    Abstract257)      PDF (1988KB)(90)       Save
    A method of clustering component assembly units with hierarchical branching for the trunks of tree structure was proposed aiming at the problems of low parallelism of assembly work and difficult analysis of feature deviation in the component assembly processes. Firstly, the component tree structure was constructed according to the assembly association among the parts, and the assembly feature association index among the branches was analyzed. The index system and the application rules were established to express the closeness between the branches, and the closeness matrix was constructed to complete the representation of the trunks of the component tree. Secondly, with the closeness between branches as the initial input, an improved Dijkstra path planning algorithm was introduced, and the optimal solution of the local shortest path between the trunk and multiple branches was obtained by using the advantages of the algorithm itself. The stem-branch hierarchy matrix was constructed to realize the stem-branch hierarchy of the component tree structure, and then the assembly unit clustering was completed by merging the branches. Finally, virtual assembly was carried out with the results of unit partition, and interference was analyzed in the physical workshops to optimize the final partition result. The feasibility and effectiveness of the proposed method were verified by an example of assembly unit clustering of a vehicle differential assembly. 
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    Braking Torque Model in Liquid-cooled Permanent-magnet Retarders Accounting for Temperature Effects
    GUO Wenguang, WANG Fei
    China Mechanical Engineering    2023, 34 (06): 685-693.   DOI: 10.3969/j.issn.1004-132X.2023.06.007
    Abstract255)      PDF (6867KB)(78)       Save
     A pre-transmission liquid-cooled permanent-magnet retarder(PMR) was proposed to solve the problems of braking torque heat-fade for conventional PMRs. The calculation models of static and transient air-gap magnetic field were established considering the influences of magnetic flux leakage in the retarders based on the magnetic equivalent circuit(MEC)and piecewise function method. The braking torque model of the PMR was obtained and verified by finite element analysis method based on the transient air-gap magnetic field model. An iterative model of braking torque considering the influences of temperature was established based on the established braking torque model and the electro-thermal coupling theory. The bench test results show that the calculated values of the braking torque model are in good agreement with the braking torque-speed characteristic test. The torque values calculated by the iterative model of braking torque considering the temperature effects are in good agreement with the continuous braking test results, and the errors are less than 7%. 
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    Thermal Mechanics Coupling Analysis of Angular Contact Ball Bearings Installed in Pairs in Feed System
    LI Zhenjun, ZHAO Chunyu
    China Mechanical Engineering    2023, 34 (07): 821-829.   DOI: 10.3969/j.issn.1004-132X.2023.07.008
    Abstract254)      PDF (5602KB)(134)       Save
    The prediction and analysis of thermal mechanics coupling performance of angular contact ball bearings was the key to ensure the working accuracy of machine tools. Based on Hertz contact theory and thermal network method, a dynamic thermal mechanics coupling model of ball screw feed system pair-installed bearings was established under working conditions, the internal lubrication state and the thermal expansion of ball bearings were considered under temperature rise effect, and a numerical calculation method was proposed for dynamic thermal mechanics coupling analysis of bearings. The time-varying laws of internal contact parameters and friction heat generation of the bearings were proved. Results show that the rotational speed and the external load affect the frictional contact characteristics of bearings, and the performance of bearings is significantly affected by the thermodynamics behavior. The dynamic thermal mechanics coupling analysis model proposed herein may effectively predict the contact characteristics of bearings under nonlinear thermal behavior. 
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