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    Chatter Identification Method for Heavy-duty Robotic Milling Systems Based on Variational Mode Filtering and Attention Mechanism
    LIANG Zhiqiang1, 2, CHEN Sichen1, DU Yuchao1, LIU Baolong1, 2, GAO Zirui1, YUE Yi3, XIAO Yubin4, ZHENG Haoran1, QIU Tianyang1, LIU Zhibing1
    China Mechanical Engineering    2025, 36 (05): 1018-1027,1073.   DOI: 10.3969/j.issn.1004-132X.2025.05.013
    Abstract1410)      PDF(pc) (7393KB)(336)       Save
    A method was proposed for identifying chatters in heavy-duty robotic milling systems by integrating variational mode filtering with fixed parameters, envelope filtering and an attention mechanism network identification. Initially, variational mode filtering theory was applied to eliminate non-chatter signal components in the high-frequency ranges by optimally selecting a quadratic penalty. Then, to swiftly identify the current machining conditions, the envelope filtering method was employed, leveraging signal time domain distribution and the frequency domain mapping law to remove the spindle speed-related signal components in the low-frequency ranges. Subsequently, a network identification model incorporating an attention mechanism was developed to identify preprocessed multi-temporal short-term signal segments for machining condition identification, followed by verification experiments on heavy-duty robotic milling systems. Experimental analysis results demonstrate that by eliminating non-chatter signals in the high-frequency ranges and spindle speed-related components in the low-frequency ranges, the accuracy of regenerative chatter identification is significantly enhanced, achieving an identification accuracy of 98.75%. Compared with alternative identification methods, the proposed method may effectively identify regenerative chatters during heavy-duty robotic milling processes, thus offering valuable technical support for future online chatter suppression of heavy-duty robotic milling.
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    China Mechanical Engineering    2025, 36 (04): 1-.  
    Abstract398)      PDF(pc) (293186KB)(306)       Save
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    Depth of Cut Control for Thin-walled Parts in Robotic Milling Based on FLADRC
    SHI Long, ZHOU Hexiang, LI Zhoulong
    China Mechanical Engineering    2025, 36 (04): 671-680.   DOI: 10.3969/j.issn.1004-132X.2025.04.003
    Abstract2434)      PDF(pc) (8675KB)(295)       Save
    Weakly rigid large thin-walled parts had large deformations and vibrations during robotic thinning machining, which led to a degradation of the surface quality of the workpieces and difficulties in ensuring the accuracy of the remaining wall thickness. To this end, a VCM-driven follower support head was used for vibration and deformation suppression, and a FLADRC based control strategy was proposed for depth of cut of robotic milling thin-walled parts. In order to verify the effectiveness of the control strategy, the system control models were firstly established based on the MATLAB/Simulink simulation and experimental platform, and the simulation analysis was carried out, then experimental verification was carried out on the thin-walled parts robotic milling experiment platform. Both of the simulation and experimental results show that the depth-of-cut control strategy based on the follower support head may significantly suppress the vibrations and deformations during the machining processes of thin-walled parts and effectively ensure the accuracy of the remaining wall thickness. In addition, compared with the traditional fuzzy PID control, the FLADRC has a better control effectiveness and exhibits higher robustness in the presence of external disturbances.
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    Development and Applications of Metal Laser Additive Manufacturing Technology for High-end Equipment
    Kai YANG, Lei WANG, Yongkai TANG, Moubin LIU, Ziao GUO
    China Mechanical Engineering    2025, 36 (09): 2068-2080.   DOI: 10.3969/j.issn.1004-132X.2025.09.019
    Abstract279)   HTML9)    PDF(pc) (3960KB)(265)       Save

    A comprehensive review of the innovative applications and development of laser additive manufacturing technology in high-end equipment manufacturing was provided. Firstly, the basic principles and advantages were introduced, including the ability to achieve integrated manufacturing of complex structures, optimized design of materials and structures, and improvement of component performance. Further, the innovative opportunities brought by laser additive manufacturing technology to high-end equipment manufacturing in aspects were discussed such as new material development, new process innovations, new structures design, and new functions integration. The challenges faced in the applications of laser additive manufacturing technology in high-end equipment manufacturing were analyzed, such as technical difficulties in material system development and new material applications, manufacturing equipment development, online monitoring and quality control technology during the manufacturing processes, and improvement of post-processing technologies. Finally, the future development trends of laser additive manufacturing technology for high-end equipment were outlooked.

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    Design of Jig and Fixture for Machining Precision Forged Blade Tenons of Aeroengine
    ZHANG Shen1, LIANG Jiawei2, WU Dongbo3, WANG Hui4, ZHAO Bing1, XU Lijun5, ZHOU Fen5
    China Mechanical Engineering    2025, 36 (04): 703-714.   DOI: 10.3969/j.issn.1004-132X.2025.04.007
    Abstract1514)      PDF(pc) (9510KB)(260)       Save
    Precision forged blades of aeroengine were a typical thin-walled parts with complex curved surface. When milling the blade tenons, it was difficult to locate and easy to produce deformations and vibrations. Aiming at the above problems, a design method of multi-point clamping fixture for precision forged blades was proposed, and a low stress hard clamping fixture was designed. Static analysis was used to optimize the clamping position, select the coping element materials and optimize the clamping method. The effectiveness of the fixture was tested by modal tests and vibration tests. The results show that the low-band amplitude of the system is reduced by 50%, the high-band amplitude by 75%, the first-order resonance frequency is increased from 210 Hz to 402 Hz, the damping ratio under the peak value is increased from 17.4% to 25.9%, the effective value of vibration displacement signals is reduced by 35%, and the machining error margin is reduced by 59%.
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    Research Progresses for Machining Characteristics and Field-assisted Techniques of γ-TiAl Alloys
    FAN Tao1, 2, YAO Changfeng1, 2, TAN Liang1, 2, SHAN Chenwei1, 2, XIA Ziwen1, 2
    China Mechanical Engineering    2025, 36 (04): 636-645.   DOI: 10.3969/j.issn.1004-132X.2025.04.001
    Abstract2046)      PDF(pc) (25364KB)(258)       Save
    γ-TiAl alloys, due to their low density, high specific strength and excellent high-temperature oxidation resistance had broad application potentials in the aerospace fields. However, due to their high brittleness and low room-temperature plasticity, they were considered typical difficult-to-machine materials, with challenges such as high cutting forces, rapid tool wear and surface defects during the machining processes. In recent years, field-assisted machining technologies provided new solutions to these issues. The material properties, machining characteristics, and surface integrity of γ-TiAl alloys were systematically analyzed, with a focus on the research progresses of field-assisted machining technologies, including their applications in reducing cutting forces, extending tool life and improving surface quality. Additionally, the current research limitations and future development trends were sorted out, aiming to provide theoretical and technical references for the efficient machining of γ-TiAl alloys. 
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    Simulation and Experimental Study of Temperature for Polishing Aero-engine Blades with Abrasive Cloth Wheel#br#
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    XIAN Chao1, 3, XIN Hongmin2, 3, DAI Hui2, CHENG Qingsi2
    China Mechanical Engineering    2025, 36 (04): 802-810.   DOI: 10.3969/j.issn.1004-132X.2025.04.017
    Abstract486)      PDF(pc) (9909KB)(248)       Save
    ANSYS software was used to simulate the instantaneous temperature fields in the polishing processes with abrasive cloth wheel using a rectangular heat source loading method. The temperature distribution on the blade surfaces and along the blade thickness direction in the polishing processes was studied, and the influences of processing parameters on the polishing temperature was explored. The results show that as the polishing process progresses, the polishing temperature distribution gradually stabilizes. When the polishing temperature stabilizes, the temperature values of the machined parts of the blade at different depths tend to be consistent, while the temperature of the machining parts decreases continuously along the depth direction; the polishing temperature gradient gradually decreases from the contact area being machined to the machined area; the polishing temperature increases with the increase of spindle speed, the effects of feed speed on the polishing temperature are not significant and the polishing temperature is positively correlated with the tangential polishing forces; the deviation rates between the measured and the simulated temperature values are not more than 10%, indicating that the good consistency and high accuracy of the simulation.
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    Effects of Forced Positioning&Clamping on Geometric and Physical Assembly Performances for Composite Structures and Collaborative Guarantee Strategies
    GUO Feiyan1, ZHANG Yongliang2, LIU Jialiang1, ZHANG Hui2
    China Mechanical Engineering    2025, 36 (04): 655-670.   DOI: 10.3969/j.issn.1004-132X.2025.04.002
    Abstract1878)      PDF(pc) (7015KB)(236)       Save
    The large-size & thin-walled aviation composite structures had low forming accuracy and huge in-plane warping deformation. The accumulation of assembly errors, unexpected geometric gaps and shape deviations were prone to occur at the joining areas. In engineering, passive reduction actions, such as applying local clamping forces was usually applied, but uneven internal stress distribution and even internal damages would be occurred, which affected the mechanical performances of the structures in service directly. Firstly, the principle of forced positioning clamping was explained, and the affection on geometric accuracy and mechanical properties of weak rigid composite parts was analyzed. Secondly, starting from the analysis of two main aspects, i.e. optimization on forced clamping process parameters before assembly, and flexible positioning force&position adjustment of fixtures during assembly, five key technologies were solved with detailed technical solutions, i.e. setting forced assembly force limits, reduction of geometric gaps, prediction of stress/damage evolution, reverse optimization of forced clamping process parameters, and precise measurement of assembly stress&damage. Then the active control of shape&force coupling and macro & micro collaborative guarantee in the clamping processes for assembly performance, could be achieved. Finally, for the composite assembly structures, from the perspective of practical engineering applications, the future working focus towards high assembly quality and efficient, and low-cost assembly goals were proposed.
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    Fast Focusing Method for Precision Vision Detection System Based on YOLOv5s
    HU Xinyu, LIU Xiyang, ZHANG Junwei, YAN Shuang, LI Yunxiang, YE Xuhui
    China Mechanical Engineering    2025, 36 (04): 864-872.   DOI: 10.3969/j.issn.1004-132X.2025.04.024
    Abstract404)      PDF(pc) (8753KB)(226)       Save
    During measurement, the visual inspection system was influenced by factors such as production accuracy and assembly errors, leading to defocused and blurred images. Consequently, a rapid focusing method for the precision visual inspection system was developed based on YOLOv5s. This method employed a combination of coarse and fine focusing strategies. Initially, the trained YOLOv5s models were utilized to search for clear imaging depth ranges with an accuracy of 97.6%, completed the coarse focusing processes within 900ms. Subsequently, the clarity evaluation function and an improved search algorithm were applied for precise focusing, swiftly identified the optimal imaging plane within the depth range. Experimental results indicate that within a defocus range of ±4 mm, the focusing accuracy reaches 0.04 mm, with an average time not exceeding 1600 ms, which reaches a 47.6% reduction compared to existing methods. This method offers rapid speed, high accuracy, and strong adaptability, making it ideally suited for online precision measurements in visual inspection systems.
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    A Robot Stiffness Identification Method Considering Weakly Rigid Joint Transmission Chain Structures and Flexible Rod Structures
    GUO Wanjin1, 2, 3, 4, LI Ru1, WANG Libin1, HAO Qinlei1, CAO Chuqing2, ZHAO Lijun2, 4
    China Mechanical Engineering    2025, 36 (05): 974-985.   DOI: 10.3969/j.issn.1004-132X.2025.05.009
    Abstract434)      PDF(pc) (7073KB)(208)       Save
    To solve the stiffness identification problem for a 3T2R highly dexterous robot with weakly rigid joint transmission chain structures and flexible rod structures, a robot stiffness identification method was proposed. Firstly, the structural characteristics of the compact and cost-effective hybrid robot configuration design and the motion characteristics for adjusting the high dexterity of operational postures were analyzed. The robot Jacobian matrix was constructed, and the end deformation model of the robot was established to analyze the influences of weakly rigid joint transmission chain structures and flexible rod structures on the robot end deformations. Then, considering the effects of weakly rigid joint transmission chain structures and flexible rod structures, along with the robotic structural characteristics of weak rigidity and large deformation, robot joint stiffness identification was carried out,and the variable stiffness modeling was completed for the mobile joint 3. Experimental results indicate that the proposed method increases the stiffness of joints 3, joint 4 and 5 by 146.59%, 30.18% and 36.07% respectively, compared to conventional stiffness identification methods. The error rates between the measured and theoretical calculation values of the overall end deformations are in 4%~6% at six selected robot poses. The capability of the proposed robot stiffness identification method was verified.
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    Study on Absolute Linear Time-grid Displacement Sensors with  Multi-frequency Magnetic Field Coupling
    YANG Jisen1, 2, 3, YUAN Junsong1, 3, XIU Fu1, 3, LIU Jiacheng1, 3, ZHANG Xiaolong1, 3
    China Mechanical Engineering    2025, 36 (05): 889-897.   DOI: 10.3969/j.issn.1004-132X.2025.05.001
    Abstract581)      PDF(pc) (8864KB)(205)       Save
    Aiming at the problems of mutual crosstalk among magnetic fields affecting the measurement accuracy of the sensors and reducing the signal-to-noise ratio when the excitation frequency of two code channels of a dual-row planar magnetic field sensor was the same, a multi-frequency magnetic field coupled absolute linear time-grid displacement sensor design scheme was proposed, which achieved the solution to the problems of eliminating the crosstalk of the magnetic fields among the code channels while solving the absolute displacement. The sensor was divided into fixed scale and dynamic scale, both using double-layer alternating structure, fixed scale using two columns of incremental code channel combination, divided into fine and coarse machines, the pairs of poles of two rows of excitation coils were two integers of the reciprocal relation, the absolute displacement measurement was realized by using the pairs of poles within the displacement difference. Precision machine measurement channel and rough machine measurement channel were input  different frequencies of the excitation current signals at the same time,  the precision machine was input the 1 MHz high-frequency current signals, the high-frequency excitation current signals might effectively enhance the inductive signals, improve the signal-to-noise ratio of the electrical processing system. Through the method of outlier frequency reduction, the sensor resolution was improved, which effectively solved the problems that it were difficult to reconcile the signal-to-noise ratio enhancement of the signals by increasing the frequency of the excitation signals and the high resolution of the sensors. Theoretical validation and error analysis of the sensors were carried out through electromagnetic simulation analysis. Finally, the experimental platform was built to carry out prototype experiments, and the experimental results show that the absolute sensor structure with multi-frequency magnetic field coupling effectively eliminates the magnetic field crosstalk between the fine and coarse machines, and the signal-to-noise ratio of the sensors is improved, with measurement errors are less than ±17.34 μm in the measurement range of 140 mm. 
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    Precise Regulation of Differential Pressures at Port of Load-sensitive Multi-way Valves Based on ADRC Algorithm
    LEI Xingmao1, DING Haigang1, 2, WANG Simin3, YANG Chengcheng1, PANG Zhizhen1
    China Mechanical Engineering    2025, 36 (05): 954-962,973.   DOI: 10.3969/j.issn.1004-132X.2025.05.007
    Abstract423)      PDF(pc) (9511KB)(184)       Save
     Load-sensitive multi-way valve was the core component for the hydraulic system of construction machinery, the pressure compensator was used to keep the differential pressure of the valve ports constant, but the differential pressure was susceptible to the spool opening and load changes, resulting in low accuracy of the main valve flow rate control.Therefore, a new type of load-sensitive multi-way valve differential pressure continuous control method was proposed, a proportional solenoid was used to push the spools of the compensator valves, and ADRC algorithm was used to control the proportional solenoid thrusts and realize the closed-loop control of differential pressures of the main valves, so as to accurately control the flow rate.Firstly, the working principle of the system was introduced and a mathematical model was established, then a simulation model was established based on AMESim-MATLAB joint simulation platform, and a test bench was built for experimental validation, the characteristics of the valve differential pressure maintenance and the main valve flow rate regulation were analyzed under the conditions of load changes and main valve opening degree changes. The results show that compared with the load changes, the changes of the main valve opening degree have a greater impact on the  differential pressures. A new type of valve port differential pressure control structure and method may accurately control the load-sensitive multi-way valve differential pressures, so as to achieve the effectiveness of precise control of the flow rate, and may actively regulate the differential pressures without changing the main valve opening degree, so as to achieve the flow rate for the further regulation.
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    Nanosecond Laser Machining of Spiral Grooves of Dry Gas Seal Rotational Ring Surfaces
    Wenqian LI, Zhanqiang LIU, Jinfu ZHAO, Bing WANG, Yukui CAI
    China Mechanical Engineering    2025, 36 (10): 2207-2214.   DOI: 10.3969/j.issn.1004-132X.2025.10.006
    Abstract347)   HTML30)    PDF(pc) (3972KB)(178)       Save

    An experimental study on the nanosecond laser processing of the spiral groove on the dry gas seal rotational ring surfaces made of GH4169 was carried out. Orthogonal tests and one-factor methods were utilized to reveal the effects of laser power, scanning speed, filling spacing and repetition frequency on the spiral groove depth and bottom roughness Ra, and to determine the appropriate combination of laser processing parameters. The results show that the greatest influence on the depth of the spiral grooves on the surfaces of GH4169 alloy is the laser power, followed by the repetition frequency and the scanning speed, and the greatest influence on the roughness of the groove bottoms is the scanning speed, followed by the repetition frequency and the scanning spacing. With the laser power of 18 W, scanning speed of 40 mm/s, fill spacing of 0.005 mm, and repetition frequency of 50 kHz, the spiral grooves on the machined rotational ring surfaces is able to meet the machining requirements of groove depth of 7 μm, and groove bottom roughness of Ra≤0.8 μm.

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    Thread Extension Stress Analysis of Bolts under Pre-tensioning Conditions
    GUAN Jiaoyue1, GAO Yuan1, AI Yanting1, TIAN Jing1, YAO Yudong2
    China Mechanical Engineering    2025, 36 (05): 923-932.   DOI: 10.3969/j.issn.1004-132X.2025.05.004
    Abstract501)      PDF(pc) (7649KB)(175)       Save
     It was difficult to accurately determine the thread stresses on the bolts under pre-tensionsing conditions, which might lead to strength fracture and premature loosening of the threads, and the reliability of the bolt joints was compromised. Currently, the contact state of the thread surfaces was usually described by stresses under an absolute coordinate system. However, the simulated stress direction was at an angle to the actual thread surface. The analysis results were not intuitive. Therefore, a thread mathematical model was derived and the extended stress analysis method of thread contact surfaces was proposed. Then, the finite element model of bolt joints was established for the structural characteristics of bolts. And the accuracy of the model was verified by tests. Finally, the extended stress analysis method was applied to study the thread surface stress and the distribution characteristics of bolts. The results show that the maximum error between the simulated preload and the testing preload is only 5.78%, where the accuracy of the simulation model is demonstrated. The extension stress analysis method may reflect the continuity and monotonicity of the stress distribution on the thread surfaces, and the method also reflects the optimal preload. The decreasing rate of the stress on the same layer thread is inversely proportional to the stress. From the stress analysis, the reason why the stresses on the thread are mainly concentrated in the first three turns is illustrated. The thread extension stress analysis method proposed herein is more intuitive and accurate. The paper may provide theoretical support for the anti-loosening analysis and reliability analysis of bolts.
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    Instantaneous Milling Force Modeling and Coefficient Calibration Method of Variable Helical Circular-arc End Mills with Unequal Rake Angle
    QI Shutao, LI Jiaqi, ZHENG Shucai, XU Jinting, SUN Yuwen
    China Mechanical Engineering    2025, 36 (04): 681-687,696.   DOI: 10.3969/j.issn.1004-132X.2025.04.004
    Abstract2259)      PDF(pc) (5531KB)(175)       Save
    Variable helical end mills with unequal rake angle maight effectively suppress milling chatters, which significantly improved the machined surface quality and simultaneously reduced the risk of tool breakages, however, due to the unequal geometric parameters of each cutting edge, the existing models had difficulty to accurately predict the cutting forces, hence, a new instantaneous milling force modeling and coefficient calibration method were proposed. Firstly, the geometry and position relational expression of the cutting edges for variable helical circular-arc end mills were given, then considering the tool runout and variation of geometrical parameters of cutting edges, an instantaneous uncut chip thickness calculation and element cutting force prediction model was established; Subsequently, a nonlinear optimization method to simultaneously calibrate the cutting force coefficients and tool runout parameters was proposed, and an efficient algorithm for solving the model parameter initial values was also given based on linear least squares and oblique cutting theory. The experimental results show that the amplitude and waveform of predicted cutting forces are consistent with the measured ones with errors of less than 15%, verifying the effectiveness of the proposed model.
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    Study on Lubricating Performances and Mechanism of Nano-carbon Balls Cutting Fluids
    SUN Hao1, LAN Qixin2, YAO Bin2, LU Jingjing1, ZHANG Jinhui2, PAN Zhirong2, ZHAO Kexin2
    China Mechanical Engineering    2025, 36 (04): 715-723.   DOI: 10.3969/j.issn.1004-132X.2025.04.008
    Abstract1779)      PDF(pc) (8056KB)(174)       Save
    Nano-carbon balls cutting fluid was applied to the cutting processes of difficult-to-machine aerospace gear steels(15Cr14Co12Mo5Ni2W), and the lubrication enhancement effects of nano-carbon particles on the cutting fluid were investigated. Firstly, a cutting force model for metal cutting was established to analyze the relationship between cutting lubrication and cutting forces. Furthermore, through combined friction-wear tests and milling experiments, the lubrication performance of nano-carbon balls cutting fluid was evaluated in terms of friction coefficient, wear volume, friction surface quality, and cutting forces. Compared with the base cutting fluid, when the mass fraction of nano-carbon is reached 0.02%, the milling forces for the gear steels are decreased by over 10%, and surface roughness is reduced by more than 15%. Experimental observations reveal that nano-carbon particles on the friction contact surfaces preferentially are adsorbed onto micro-peak regions with higher surface free energy, forming a nano-carbon adsorption film. Lubrication mechanism analysis indicates that this adsorption film may exert a friction-reducing “micro-bearing” effects.
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    Study on Low Wear Machining Method of High Volume Fraction SiCp/Al Composite Materials by ECM-mechanical Combined Machining Processes Method
    HE Bin, ZHOU Xingyu, LU Hongyu, ZHANG Junfei, DING Kai, LI Qilin, LEI Weining
    China Mechanical Engineering    2025, 36 (04): 753-759.   DOI: 10.3969/j.issn.1004-132X.2025.04.012
    Abstract590)      PDF(pc) (12862KB)(163)       Save
    To improve the problems of tool wear, poor surface quality and low machining efficiency of aluminum-based silicon carbide(SiCp/Al) composites with high volume fraction under conventional machining, an ECM-mechanical combined machining method was proposed, and the ECM-mechanical combined machining experiments of 60% volume fraction SiCp/Al composites were carried out. The results show that SiC particles are exposed on the surfaces with the removal of aluminum matrix. There is a certain depth of transition zone between the surface of the workpiece and the matrix after ECM, the aluminum matrix in the transition zone is locally removed, and the binding force of SiC particles is reduced. When the diamond grinding rod is used for machining the transition zone, the aluminum matrix adhesion phenomenon is not observed, the diamond grinding rod has almost no wear, and the surface damages are obviously reduced. The machinability of high volume fraction SiCp/Al composites may be improved by ECM-mechanical machining processes.
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    Molecular Dynamics Simulation of Microscopic Crack Initiation and Extension Mechanism in 8Cr4Mo4V Bearing Steels
    Tianyu MA, Gu GONG, Hongrui CAO, Jianghai SHI, Xunkai WEI, Lijun ZHANG
    China Mechanical Engineering    2025, 36 (10): 2179-2189.   DOI: 10.3969/j.issn.1004-132X.2025.10.003
    Abstract461)   HTML23)    PDF(pc) (7456KB)(156)       Save

    To investigate the influences of cementite on the mechanics properties of the matrix and the initiation and propagation of microcracks in 8Cr4Mo4V bearing steels, molecular dynamics models were used to systematically analyze the effects of cementite's geometric parameters (such as shape, size, and position) on crack initiation and extension mechanism. And combined with cohesive force theory, the characteristics of interface crack propagation were studied. The results indicate that cementite significantly enhances the mechanics properties of the bcc-Fe matrix, with smaller cementite particles providing a more pronounced strengthening effectiveness. While the shape and position of cementite exert a relatively minor impact on overall mechanics performance, sharper inclusions accelerate crack propagation, and the position of inclusions determines the crack propagation path. Furthermore, interfaces between the bcc-Fe matrix and cementite, as well as twin boundaries with larger misorientation angles, exhibit increased resistance to crack initiation and propagation.

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    Research on Precision Control of Large Deployable Antennas Driven  by Fusion of Data and Model
    JIANG Donglei1, ZHAO Qiangqiang1, WU Tengfei1, MA Jia2, JIA Kang1, HONG Jun1
    China Mechanical Engineering    2025, 36 (05): 898-910.   DOI: 10.3969/j.issn.1004-132X.2025.05.002
    Abstract466)      PDF(pc) (7097KB)(155)       Save
    In order to improve the surface precision of large deployable planar antennas efficiently and accurately by adjusting the truss system, the surface precision prediction and accuracy verification were realized from two aspects of finite element simulation analysis and photogrammetry. According to the principle of mechanics of materials and temperature equivalence theory, the simulation model of plane antenna surface precision was constructed. A rapid measurement system of surface accuracy was established based on photogrammetry. The variable confidence Gaussian process model was established by combining the finite element simulation samples and the photogrammetry measured samples, and the precision was optimized and adjusted by Bayesian optimization. The accurate prediction and on-site rapid adjustment of large planar antenna precision were realized, which may provide simulation analysis model support for forward precision evaluation and inverse optimization adjustment of large planar antennas. 
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    Lightweight Design of Concrete Pump Truck Boom Pins Based on Multi-fidelity Surrogate Model
    LI Peng1, 2, 3, 4, LI Mengcong1, 4, XIAO Libo2, 3, WANG Yitang1, 4, SONG Xueguan1, 4, YANG Ling5
    China Mechanical Engineering    2025, 36 (04): 821-829.   DOI: 10.3969/j.issn.1004-132X.2025.04.019
    Abstract443)      PDF(pc) (9820KB)(149)       Save
    As a key connecting and supporting component in a concrete pump truck boom system, how to reduce the mass of the pin shafts was a noteworthy issue in boom design. A parameterized finite element model of the hollow dumbbell pin shafts was constructed based on control parameters. Then, a more accurate feature mapping based MFS(FM-MFS) model was established through the mutual disturbance of high and low fidelity models and the reasonable allocation of high and low fidelity data. Genetic algorithm was used for optimization to obtain the optimal design scheme for the hollow dumbbell pins based on this surrogate model, achieving a weight reduction of 36%. Through theoretical, simulation, and experimental verification, it is shown that the hollow dumbbell pin shafts constructed based on the optimal parameters of the surrogate model may achieve lightweight and material consumption savings while still ensuring the physical and mechanical properties, which provides data support and reference for further applications in the future. 
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    Aerodynamic Optimization of Radial Turbines Based on Surrogate Model of Pre-screened Strategies and DFFD Parameterization
    Tianqi WANG, Jiang CHEN, Hang XIANG, Xiaofei SONG
    China Mechanical Engineering    2025, 36 (10): 2171-2178.   DOI: 10.3969/j.issn.1004-132X.2025.10.002
    Abstract342)   HTML22)    PDF(pc) (3107KB)(148)       Save

    There were some problems such as difficult geometric control, many control variables and low optimization efficiency in aerodynamic optimization of three-dimensional complex blade surfaces of radial turbines. To solve these problems, multi-degree-of-freedom parameterization of radial turbine runner and blade multidimensional geometry were implemented based on DFFD method. Then an differential evolution algorithm assisted by surrogate models of pre-screened strategies(Pre-SADE) was introduced. Finally, a data-driven three-dimensional aerodynamic optimization platform for centripetal turbines was constructed by combining python and batch script of process automation. The platform was used to carry out the joint optimization design of flow channel-static/rotating blades for the radial turbines. The results show that after optimization, the adiabatic efficiency and mass-flow of the design point of the centripetal turbines are increased by 1.66% and 1.7% respectively, which effectively reduces the shock intensity in the guide vane channel and the shock loss on the suction surfaces of the guide vane, and the efficiency characteristics of the design rotational speed are improved in all working conditions. Finally, the method and platform may ensure the aerodynamic optimization efficiency, and effectively reduce the optimization variables and sample real evaluation times, significantly improve the optimization efficiency, and meet the rapid and elaborate optimization design requirements of radial turbines.

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    A Novel Deformable Serial Pipeline Inspection Robots:Design, Modeling and Experimentation
    Yixin ZHANG, Yinan MIAO, Zhiheng YI, Wenjing WAN, Xingjian WANG, Song ZENG, Shaoping WANG
    China Mechanical Engineering    2025, 36 (09): 2140-2149.   DOI: 10.3969/j.issn.1004-132X.2025.09.026
    Abstract395)   HTML12)    PDF(pc) (4346KB)(145)       Save

    In response to the urgent demands for daily maintenance and inspection of oil and gas pipelines, a novel modular pipeline inspection robot named RoboChain-Ⅰ, featuring adaptive deformation capabilities, was proposed herein. Unlike most wheel-based pipeline robots, the robot adopted a cell-inspired modular biomimetic design with more flexible joint redundant rotational degrees of freedom(DOF), allowing the robot to actively deform in response to pipelines with varying shapes and diameters. Each module was equipped with dual-wheel independent drive, and a pair of pitch and yaw actuation mechanisms were installed at the front and rear. The modules were connected by passive elastic damping support structures or controllable electromagnetic adhesion-separation rigid structures, which improved the robot's ability to navigate complex pipelines and adapt to various environments. The forces acting on the robots during their motions inside the pipeline were modeled, and kinematics simulations were conducted using Adams. The selection of design parameters for the model was validated accordingly. A comprehensive series of experiments were conducted to evaluate RoboChain-Ⅰ's performance, including terrestrial locomotion, straight pipe traversal, elbow pipe navigation, diameter-varying pipeline adaptation, and active mother-child separation. Experimental results validate the robot's effectiveness and reliability in performing inspection tasks within complex three-dimensional pipeline networks with diameters ranging from 175~440 mm, demonstrating maximum velocities of 0.87 m/s on flat surfaces and 0.4 m/s within pipelines.

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    Cross-domain Fault Diagnosis of Bearings Based on Joint Subdomain Contrast Alignment
    YANG Kang1, CHEN Xuejun1, 2, ZHANG Lei3, LIU Feng3
    China Mechanical Engineering    2025, 36 (05): 1065-1073.   DOI: 10.3969/j.issn.1004-132X.2025.05.018
    Abstract2051)      PDF(pc) (5744KB)(144)       Save
    The fault data of bearings exhibited significant distribution discrepancies under varying operating conditions, relatively low diagnostic accuracy was resulted in practical fault detection models. Additionally, most existing research on cross-domain bearing fault diagnosis primarily emphasized inter-domain alignment and intra-class comparison, while neglecting the influences of interactions between subdomains. Therefore, a cross-domain fault diagnosis method of bearings was proposed based on joint subdomain contrast alignment. In order to highlight the fault features, the bearing vibration signals were transformed into time-frequency graph by short-time Fourier transform, and the fault features were obtained by inputting them into the feature extraction module. Domain adaptation methods achieved cross-domain recognition by transferring knowledge learned from the source domain to the target domain. During the domain adaptation processes, a joint subdomain contrast alignment strategy was used to bring samples from the same subdomain closer together while separating samples from different subdomains, which aligned the subdomain distributions of the same class samples among the source and target domains, thereby enhancing the models generalization ability in the target domain. Resnet34 was used as the feature extraction network on the model architecture, and the maximum mean difference was used at the output of the network to align the global distribution of the source domain and the target domain. Compared with the classical domain adaptation methods, the experimental results on the bearing fault data set of Case Western Reserve University shows that the cross-domain fault diagnosis method of bearings based on joint subdomain contrast alignment has better feature transfer ability. 
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    A Reliability Allocation Method Considering Distribution and Transmission Models for Mechanical Systems
    WANG Zhichao1, LIU Chao1, RAN Yan2, CHEN Yifan3, JIANG Dongxiang1, ZHANG Genbao2, 3
    China Mechanical Engineering    2025, 36 (06): 1143-1150.   DOI: 10.3969/j.issn.1004-132X.2025.06.001
    Abstract483)      PDF(pc) (1184KB)(141)       Save
    To address the problems of the allocation reliability of lower-level units being greater than that of the upper-level unit in the multi-layer structure reliability allocation of mechanical systems, a novel reliability allocation method was proposed. Firstly, the mechanical systems were divided into a system-function-motion-action(SFMA) hierarchy structure. Then, according to the hierarchy structure consisting of distribution and transmission models, the reliability allocation techniques were proposed by combining the minimum cost method and reliability function, and the reliability allocation models of the mechanical systems, function units, motion units, and sub-motion units were established from top to bottom. Finally, taking the gear grinding machine as an example, the feasibility and effectiveness of the proposed method were verified.
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    Spiral Machining Trajectory Planning Method Based on Discrete Point Cloud Construction of Radial Lines
    WU Jiangsheng, CHAI Xingliang, BO Qile, LIU Haibo, WANG Yongqing
    China Mechanical Engineering    2025, 36 (04): 697-702,714.   DOI: 10.3969/j.issn.1004-132X.2025.04.006
    Abstract1504)      PDF(pc) (7105KB)(140)       Save
    Aiming at the problems that it was difficult to directly generate efficient and accurate continuous smooth tool path trajectories based on discrete point clouds, a method to directly construct radial lines on point cloud and generate spiral machining trajectories through radial line interpolation was proposed herein. For the construction of radial lines, a boundary recognition method was proposed based on feature descriptors to extract boundary points as two end points of the radial lines. Taking the optimal discrete geodesics between two end points on the point cloud as the radial point set, the curvature minimization problems of discrete geodesics were proposed and solved by Newton iteration method. The B-spline curves were used to fit and resampling according to the residual height based on the radial point sets. The radial line interpolation algorithm was proposed to generate the spiral machining trajectory with equal residual height. Finally, an example was given to demonstrate the spiral machining trajectories directly generated by the point cloud data, which fully verified the effectiveness of the proposed method.
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    China Mechanical Engineering    2025, 36 (04): 0-.  
    Abstract261)      PDF(pc) (369KB)(139)       Save
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    Design and Experimental Research of RV Reducer Main Bearing Test Benches
    Qingwang ZHU, Jing ZHANG, Faxiang XIE, Zhonggang ZHU, Jianyu GUO, Houlin YAN
    China Mechanical Engineering    2025, 36 (08): 1749-1756.   DOI: 10.3969/j.issn.1004-132X.2025.08.010
    Abstract372)   HTML3)    PDF(pc) (2901KB)(137)       Save

    In order to obtain the overturning stiffness and fatigue performance of RV reducer main bearing, a main bearing test bench was developed, which might accurately measure the overturning stiffness and fatigue life of RV reducer main bearings. The working principle and detailed structure of the test bench were emphatically introduced. The main bearing test bench consisted of mechanical systems, electric control systems and measurement software. The overturning stiffness of RV-125N reducer with different main bearing preloads was tested, and the fatigue test of RV-125N reducer with main bearing preload of 0.06 mm was carried out, and the failure mode and principle of the main bearing after the fatigue test were discussed. A three-dimensional analytical model of the RV-125N reducer was developed based on the experimental conditions in Masta software, and the life of the main bearing of RV-125N reducer was simulated and analyzed, and the simulation results show that the theoretical lifetime is 89% of the actual lifetime. The development of the test bench solves the problems of inaccurate overturning stiffness tests of the main bearings and the difficulty of fatigue life verification,and provides theoretical value and practical application value for the design and manufacture of RV reducers.

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    Research Progresses of Current Carrying Tribological Behavior of Materials under Influences of Service Environment
    SHEN Mingxue, CHEN Siyang, WU Haihong, XIAO Li, Wang Nenghui, JI Dehui
    China Mechanical Engineering    2026, 37 (1): 2-13.   DOI: 10.3969/j.issn.1004-132X.2026.01.001
    Abstract203)   HTML24)    PDF(pc) (3860KB)(134)       Save

    The research progresses on current-carrying tribological behavior of materials under service environmental influences were reviewed herein. It was summarized that the tribological performance and the dynamic evolution of electrical arcs under various environmental conditions such as humidity, temperature, atmosphere, crosswind, and air pressure. The mechanism of current-carrying wear under different service environments was clarified, along with the roles of third‑body media (e.g., water, ice, oxide films) induced by the environments in wear damage and arc erosion of the friction pairs. The intrinsic relationship between external environmental factors and material damage in current-carrying friction pairs was revealed to advance the development of current-carrying friction theory.

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    Intelligent Decision-making for Assembly Processes of Micro-device Products
    Lingling SHI, Yimin DU, Lili GUO, Zhijing ZHANG, Xin JIN, Jiadi LI
    China Mechanical Engineering    2025, 36 (10): 2159-2170.   DOI: 10.3969/j.issn.1004-132X.2025.10.001
    Abstract394)   HTML40)    PDF(pc) (27673KB)(133)       Save

    To solve the problems that the assembly process planning of micro-device products relies on manual experience heavily, a knowledge-driven fine-grained micro-device assembly process planning method was proposed. And a micro-device assembly process decision software integrating product and system knowledge was developed. This planning method took the resource constraints of the assembly systems into account, and planned the assembly processes of micro-devices from process, steps, and process parameters. Based on interval-type hesitant fuzzy entropy, a mixed attribute matching weight parameter determination method ensured the effectiveness of the process decision algorithm. The developed decision system realized rapid decision-making of the assembly processes of micro-device products.

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    Multi-objective Trajectory Planning of Manipulators Based on Improved SSA
    Jianlin LIU, Haisong HUANG, Qingsong FAN, Chi MA, Langlang ZHANG
    China Mechanical Engineering    2025, 36 (09): 2047-2056.   DOI: 10.3969/j.issn.1004-132X.2025.09.017
    Abstract298)   HTML1)    PDF(pc) (5244KB)(132)       Save

    To optimize the three objectives of efficiency, energy consumption and impacts at the same time, a multi-objective trajectory planning model was proposed based on an improved SSA. Firstly, the artificial potential field method (APF) was used for path planning to obtain the shortest and collision-free path of the manipulator grasping the materials, and the key motion sequence was extracted to establish a multi-objective function. Then, aiming at the problems of multi-objective salp swarm algorithm (MSSA), such as poor diversity of initial population, easy to fall into local optimum and slow convergence in solution set space, an improved algorithm namely logistic-sine multi-objective salp swarm algorithm(LMSSA)was proposed. The algorithm combined logistic-sine chaotic mapping, pinhole imaging learning strategy and golden sine development strategy to optimize the control nodes of the seventh-order B-spline curve and complete the multi-objective motion trajectory planning of the robotic arms. Finally, the trajectory planning model was applied to the actual grasping tasks of the manipulator UR16e by building MATLAB-CoppeliaSim-UR16e experimental platform. Experimental results show that based on LMSSA, the manipulator motion planning method realizes the accurate, efficient and energy-saving motion trajectory planning of the manipulator, and is successfully applied to the actual operation scenes.

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    Experimental Study of Characteristics of Gas Pressure Reducing Valves under Different Working Conditions
    Bin QIN, Jiaxu HAO, Jingwen LIN, Quan ZHANG
    China Mechanical Engineering    2025, 36 (11): 2477-2485.   DOI: 10.3969/j.issn.1004-132X.2025.11.001
    Abstract297)   HTML10)    PDF(pc) (1718KB)(131)       Save

    Pressure reducing valves were often used in gas pipeline systems to control the downstream pressure. At present, the pressure reduction range of conventional small pressure reducing valves was small, and it was difficult to meet the pressure reduction demands under ultra-high pressure. A small pressure reducing valve with adjustable output pressure under ultra-high pressure was proposed, with an input pressure of 19~60 MPa and an output pressure of 7~13 MPa. By establishing a test platform and setting different upstream pressure and downstream resistance of the pressure reducing valves, the stability of the performance of the pressure reducing valves and the characteristic change were studied under four types of working conditions. Through experimental validation, the pressure reducing valve may maintain stable downstream pressure in ultra-high pressure usage scenarios. The response time of the valves after the pipeline connection is between 0.5 and 6.0 seconds, with pressure fluctuations within 10 seconds after response being between 0.12% and 4.49%. The results indicate that the trend of pressure changes after the reducing valves are related to the upstream pressure: when the upstream pressure decreases, the output pressure first declines and then rises, while when the upstream pressure is stable, the output pressure tends to decrease. The results may guide the applications of the pressure reducing valves in hydraulic systems.

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    Statistical Analysis of Planetary Roller Screw Thread Machining Errors and Comparative Study at Home and Abroad
    Siqi LIU, Peitang WEI, Rui HU, Xuesong DU, Li LUO, Caichao ZHU, Pengliang ZHOU
    China Mechanical Engineering    2025, 36 (08): 1713-1727.   DOI: 10.3969/j.issn.1004-132X.2025.08.007
    Abstract361)   HTML5)    PDF(pc) (4720KB)(130)       Save

    PRSM was a new type of precision threaded transmission mechanisms. Currently, due to the difficulty in grinding small pitch hard tooth profile precision threads, ensuring the machining accuracy of PRSM precision threads was challenging, which led to a significant gap between domestic and foreign products in terms of load-bearing capacity, travelling accuracy and transmission efficiency and other performance aspects. This paper selected typical PRSM products from domestic and foreign markets to conduct statistical, analytical, and comparative research on thread machining errors. First, the axial profile of the screw, roller and nut thread was detected based on the contact measurement method. Evaluation techniques such as gradient threshold method and axis transformation theory were employed to assess and statistically analyze errors including pitch diameter errors, pitch errors, eccentricity errors, and tooth profile angle errors. Based on these analyses, the paper elaborated on the mechanism behind typical irregularities in PRSM thread machining, such as taper in pitch diameters and periodic fluctuations in multi-start thread pitchs. Furthermore, corresponding process optimization strategies were proposed for quality control in thread machining, aiming to support efficient precision grinding and performance enhancement of domestic PRSM threads.

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    Influence Law and Mechanism of Geometric Parameters on Wrinkling Characteristics of Hollow Aluminum Profiles in Stretch-Bending#br#
    LIU Zhiwen1, 2, LEI Chong1, SUN Kaibo1, OUYANG Basheng1, LI Luoxing2, LIU Xiao3, LI Fazhi1
    China Mechanical Engineering    2025, 36 (05): 1083-1093.   DOI: 10.3969/j.issn.1004-132X.2025.05.020
    Abstract1837)      PDF(pc) (8620KB)(130)       Save
    Based on the plate and shell theory, the expression of wrinkling energy and external force work functions of hollow aluminum profiles in stretch-bending were derived. Combined with the energy criterion, the theoretical prediction model of wrinkling was established for hollow profiles in stretch-bending and the accuracy of model was verified by bending experiments. The formation mechanism of wrinkling defects in stretch-bending of hollow profiles was revealed and the influences of geometric parameters on wrinkling limit and morphology were quantitatively studied. The results show that the theoretical predictions of the number and height of wrinkling under three different bending radii are in good agreement with those of the experimental ones. The maximum differences are as 1.2 and 0.55 mm, respectively, with relative errors of 16.93% and 11.28%, respectively. The growth rate of external force work in the bending stages is greater than that of wrinkling energy. With the increase of bending time, the external force work is greater than the wrinkling energy, resulting in the appearance of wrinkling instability. With the increase of thickness-to-height ratio and thickness-to-width ratio of the profiles, the wrinkle ratio and wrinkling number decrease, while the wrinkling limit and wrinkling height increase. With the increase of the aspect ratio, the wrinkle ratio and wrinkle height increase, while the wrinkling limit and wrinkling number decrease. The wrinkling limit might be increased by adding inner reinforcement rib in the profile cavities, while the wrinkling number increases and the wrinkling height decreases. 
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    China Mechanical Engineering    2025, 36 (04): 882-887.   DOI: 10.3969/j.issn.1004-132X.2025.04.026
    Abstract353)      PDF(pc) (1444KB)(129)       Save
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    Analysis and Optimization of Meshing Performance of Straight Bevel Gears Machined by Dual Interlocking Circular Cutters
    Jinzhan SU, Yaoke FENG, Bin LIU, Xinlong CAO, Linlin SUN
    China Mechanical Engineering    2025, 36 (08): 1683-1690.   DOI: 10.3969/j.issn.1004-132X.2025.08.004
    Abstract316)   HTML3)    PDF(pc) (1896KB)(129)       Save

    A method for milling/grinding straight-toothed bevel gears using high-efficiency double-arc cutting tools was proposed to improve their meshing performance. A double arc tool was used to simulate a crown-producing wheel, and tool trimming coefficients, the average radius of the cutter disk and the cutting edge angle were introduced to establish a straight bevel gear tooth face model that considered tooth profile and tooth direction trimming. According to the conditions of continuous tangency of two meshing gears, a tooth contact analysis model was established, and combined with tooth clearance, normal flexibility matrix and mathematical planning, a wheel tooth bearing contact analysis model was established. Then with the goal of achieving symmetry in geometric transmission errors and minimising fluctuations in load transmission errors, the tool profiling origin positions was adjusted and tool parameters were optimised. The geometric transmission errors and load transmission errors of the gear were compared before and after optimization. The example results show that the position of the tool reshaping origin affects the symmetry of the geometric transmission errors; the larger the tool reshaping coefficient is, the larger the amount of tooth profile reshaping is, the amplitude of the geometric transmission errors and the amplitude of the load bearing transmission errors will increase; with the decrease of the average radius of the knife holder and the increase of the blade angle, the amount of tooth profile reshaping is increased, and then the area of the tooth surface mark will be reduced. After optimization, the amount of bearing transmission error fluctuation is reduced by 56.54% under the working load, which may effectively reduce the vibration excitation of the gear pairs.

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    Research on Pressure Stabilization for Loading Cylinders under Centrifu-gation Supergravity Environment Based on Experimental Tests
    Bingjing QIU, Muhua JIA, Yinqi LI, Liubin JI
    China Mechanical Engineering    2025, 36 (08): 1651-1657.   DOI: 10.3969/j.issn.1004-132X.2025.08.001
    Abstract373)   HTML9)    PDF(pc) (2744KB)(128)       Save

    To solve the problems of excessive pressure fluctuations in the simulation environment of high gravity centrifugal environment without an external oil source, the factors causing pressure fluctuations were analyzed, and experimental tests were conducted on each factor. Based on the analysis of each factor, an accumulator stabilization scheme was proposed, and the effects of accumulator working parameters, working pressure, and working medium parameters on stabilization performance were compared under different deformation conditions of specimens through supergravity experiments. The experimental test results show that within the temperature range of 36~42.5 ℃, the pressure fluctuation of oil caused by temperature changes is less than 4%. The deformation of the specimen is the main factor affecting pressure fluctuations, with a pressure fluctuation ratio of up to 47% caused by a deformation of 1 mm in the samples. The fluctuation ratio of the accumulator during pressure stabilization under supergravity is proportional to the working pressure and the deformation of the specimen. The use of two 300 mL gas volume accumulators may achieve the requirement of less than 10% internal pressure fluctuation of 20 MPa, which is consistent with theoretical calculations. The test provides technical support for controlling pressure fluctuations in high-temperature and high-pressure devices under supergravity environments.

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    Energy Consumption Anomaly Detection of Automobile Painting Drying System Based on TCN-GAT and Hybrid Neural Network
    Congbo LI, Hewang ZHAI, Wei WU, Ke DONG, Xiangfei ZHANG
    China Mechanical Engineering    2025, 36 (08): 1864-1874.   DOI: 10.3969/j.issn.1004-132X.2025.08.021
    Abstract268)   HTML0)    PDF(pc) (5941KB)(128)       Save

    A method was proposed based on TCN-GAT and hybrid neural networks for identifying anomalies in energy usage for drying systems. First, a multi-scale temporal convolutional network (TCN) and a multi-head graph attention network (GAT) were introduced to capture the temporal and spatial properties of temperature, pressure, and other variables, respectively. An anomaly detection model was built upon a combination of back propagation neural network (BPNN) and variational autoencoder (VAE). Furthermore, an energy consumption anomaly index was formulated based on prediction errors and reconstruction probability. The peak over threshold (POT) model was utilized to fit the Pareto distribution and establish an anomaly threshold. Finally, a case study was carried out at the painting workshop of a Chongqing automobile manufacturer, where Internet of Things (IoT) devices were used to gather real-world data. Data analysis was implemented to verify the effectiveness and superiority of the proposed method.

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    Identification and Evaluation of Key Error Elements in Complex Composite Aviation Componts Assembly Driven by Mechanism and Data Model Fusion
    GUO Feiyan1, ZHANG Hui2, SONG Changjie1, ZHANG Shuo1
    China Mechanical Engineering    2025, 36 (07): 1530-1543.   DOI: 10.3969/j.issn.1004-132X.2025.07.016
    Abstract1613)      PDF(pc) (6423KB)(127)       Save
     In composite assembly of complex aviation products, the factors such as part deformations under loads, numerous parameters and so on were considered. Deformation error source models for key assembly links caused by positioning and clamping, joining and rebounding were analyzed, and the Jacobian sensor matrix representing error transmission relationship was modified to establish assembly error transmission mechanism model. A support vector regression model was established based on assembly error data, a fusion model of mechanism model and data model was gained. With the predication and compensation model for the calculated values of the error mechanism model and the actual deviation, a Sobol sensitivity analysis method was adopted to calculate the global sensitivity coefficients of different assembly error links, and the key error elements affecting assembly accuracy was identified. Finally, the assembly of wing box component was taken as an example to prove the effectiveness of the proposed method.
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    Rotor Unbalance Recognition Based on Multidimensional Complex Feature Fusion and CNN-GRU
    Jianjian WANG, Yuhe LIAO, Lei YANG, Jiutao XUE
    China Mechanical Engineering    2025, 36 (09): 1905-1915.   DOI: 10.3969/j.issn.1004-132X.2025.09.001
    Abstract387)   HTML10)    PDF(pc) (3434KB)(126)       Save

    The existing unbalance identification algorithm without trial weight adopted an optimization algorithm framework and approximated the optimal solution through numerous iterative operations. However, such strategies typically faced the limitations of slow convergence speed and the tendency to fall into local extrema. Therefore, neural networks were used to directly learn and analyze the complex mapping relationship between unbalance vibration response and unbalance, thus realizing high-precision unbalance identification. A sufficient unbalance vibration dataset with labels was constructed by simulating the rotor dynamics model. A feature fusion mechanism was designed to address the multi-dimensional complex-valued characteristics of unbalanced data. At the core algorithm level, a CNN-GRU hybrid model was constructed. In this model, CNN was responsible for extracting local spatial features from vibration data, while GRU captured temporal dependencies within the vibration data. By integrating information from both spatial and temporal domains, the model’s generalization ability and recognition accuracy were significantly enhanced. The unbalance recognition results of test set data and experimental bench demonstrate that this method may accurately predict the unbalance of the rotors, providing a rapid and accurate guide for dynamic balancing in the field without trial weights.

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    Tribological Properties of Polyelectrolyte-Modified PEEK Composite Materials
    GAO Chuanbao, ZHANG Xinyue, CEN Jiajia, CHEN Qin, FENG Haiyan, CHEN Kai, ZHANG Dekun
    China Mechanical Engineering    2026, 37 (1): 14-21.   DOI: 10.3969/j.issn.1004-132X.2026.01.002
    Abstract148)   HTML25)    PDF(pc) (2572KB)(124)       Save

    To enhance the tribological properties of PEEK, a “modify-then-form” approach was proposed. Hydrophilic SPMK was grafted onto the PEEK powder surface via UV-induced polymerization, then the PEEK-SPMK composites were prepared by hot-pressing. The friction and wear behaviors of modified PEEK under various operating conditions were analyzed, revealing the influence mechanism and lubrication mechanism of polyelectrolyte SPMK powder modification on the tribological behavior of PEEK composites.Results indicate that SPMK powder modification significantly enhances PEEK surface wettability. The friction coefficient(0.028) and wear rate(5.6×10-7 mm³/(N·m)) of PEEK-SPMK in physiological saline are markedly reduced compared to pure PEEK.

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