Most Download articles

    Published in last 1 year | In last 2 years| In last 3 years| All| Most Downloaded in Recent Month | Most Downloaded in Recent Year|

    In last 2 years
    Please wait a minute...
    For Selected: Toggle Thumbnails
    Research Progresses of Superhydrophobic Surface Processing Technology and Abrasion Resistance
    HUANG Yun, HUANG Jianchao, XIAO Guijian, LIU Shuai, LIN Ouchuan, LIU Zhenyang
    China Mechanical Engineering    2024, 35 (01): 2-26.   DOI: 10.3969/j.issn.1004-132X.2024.01.001
    Abstract1095)      PDF(pc) (50387KB)(881)       Save
    The abrasion resistance of currently prepared superhydrophobic surfaces is generally poor, which limite the applications in various fields. Studied results found that micro-nano structure and low surface energy were the key factors to achieve superhydrophobic properties. Firstly, based on the mechanism of superhydrophobic surface, the superhydrophobic surface texture was summarized, aiming to solve the wear-prone challenge of micro-nano structures by optimizing the surface texture. Secondly, the superhydrophobic surface processing technology was summarized, and measures to reduce surface energy were analyzed in terms of cost and efficiency which might provide ideas for expanding the superhydrophobic surface processing system. Then, the means of analyzing the abrasion resistance of superhydrophobic surfaces were concluded in detail and the methods of improving the abrasion resistance of superhydrophobic surfaces were described. Finally, the future development prospects of abrasion resistant superhydrophobic surfaces was prospected, with a view to promote the large-scale applications of superhydrophobic surfaces in engineering.
    Reference | Related Articles | Metrics | Comments0
    A Topology Optimized Design Method for High-performance Structures with Fluid-thermal-mechanics Coupling
    LI Rongqi, YAN Tao, HE Zhicheng, MI Dong, JIANG Chao, ZHENG Jing
    China Mechanical Engineering    2024, 35 (03): 487-497.   DOI: 10.3969/j.issn.1004-132X.2024.03.011
    Abstract1075)      PDF(pc) (5000KB)(800)       Save
    The rapid advancement of topology optimization and additive manufacturing technology provided efficient methods for designing and manufacturing high-performance complex equipment. However, current topology optimization techniques for high-performance structures only considered the design of thermal-mechanics coupling or fluid-thermal coupling, and were mostly limited to simple structures. The design under the combined effects of fluid-thermal-mechanics fields was not considered, which restricted the enhancement of structural performance. This paper tackled the challenge of designing high-performance complex structures under multi-physics fields, encompassing fluid-thermal-mechanics interactions. A topology optimization method was proposed to enhance the ability to withstand temperature of intricate structures. Firstly, the governing equations of flow field, temperature field and structural displacement field were introduced to provide a unified description of the fluid-solid materials within the computational domain. Secondly, the topology optimization model was formulated with fluid-thermal-mechanics coupling. The objective function was set to minimize the average temperature, while flow energy dissipation and structural compliance served as constraint functions. Sensitivity analysis of design variables was carried out by using a combination of the variational method and Lagrangian function. Finally, the established topology optimization model was applied to the structural design of a turbine, resulting in a structure suitable for additive manufacturing with excellent heat dissipation performance and well-balanced flow channel distribution.
    Reference | Related Articles | Metrics | Comments0
    Study on Influences of Ni Content, Nitriding Hardening Depth, and Shot Peening on Bending Fatigue Performance of 42CrMo Gears
    WU Zhongrui, CHEN Difa, WU Jizhan, YANG Yudian, LIU Huaiju
    China Mechanical Engineering    2024, 35 (03): 394-404.   DOI: 10.3969/j.issn.1004-132X.2024.03.002
    Abstract569)      PDF(pc) (9652KB)(750)       Save
     Single tooth bending fatigue tests were conducted on 42CrMo gears with different combinations of Ni content, nitriding hardening depth, and shot peening. The effectiveness of different process combinations on improving the bending fatigue limit of gears was investigated, providing process guidance for gear fatigue resistance manufacturing. Additionally, the contribution of surface hardness, nitriding hardening depth, surface residual stress, and Ni content to the bending fatigue limit of gears with different process combinations was analyzed using the random forest algorithm. A multiple regression model considering surface hardness, nitriding hardening depth, surface residual stress, and Ni content was established to predict the bending fatigue limit of gears. Comparing the predicted values with experimental values, the maximum error is controlled within 7.80%, providing a theoretical basis for the rapid and low-cost assessment of gear bending fatigue limit in engineering applications.
    Reference | Related Articles | Metrics | Comments0
    A Bionic Bouncing Robot Design and Made Inspired by Locusts
    WANG Kaidi, CHEN Suifan, TANG Wei, QIN Kecheng, LI Qipeng, YANG Zhan, LIU Yang, ZOU Jun
    China Mechanical Engineering    2023, 34 (24): 2946-2951.   DOI: 10.3969/j.issn.1004-132X.2023.24.006
    Abstract877)      PDF(pc) (3896KB)(639)       Save
     In order to improve the mobility of small robots and increase the diversity of movement gait, a jumping robot imitating locust bouncing was designed based on the body structure and movement mechanism of locusts, and the main body was made by 3D printing. And for reproducing the locusts bouncing mechanism, a torsion spring was installed at the joints of the robot body to simulate the locusts SLP(semilunar energy storage) mechanism. When the robot met an obstacle, the torsion spring released the stored elastic potential energy and generated a ground reaction force, which realized the robots bouncing and thus crossed the obstacle. The robot might imitate the locusts jumping actions, and simulate the locusts flexibility to a certain extent. It was experimentally verified that the robot has good jumping performance, with a jumping distance of up to 100 cm and a jumping height of up to 120 cm which is about 15 times of the own length.
    Reference | Related Articles | Metrics | Comments0
    Inverse Kinematics Solution of Robots Based on IQPSO Algorithm
    CHEN Zhuofan, ZHOU Kun, QIN Feifei, WANG Binrui
    China Mechanical Engineering    2024, 35 (02): 293-304.   DOI: 10.3969/j.issn.1004-132X.2024.02.014
    Abstract660)      PDF(pc) (9273KB)(539)       Save
    Aiming at the problems of singular pose, non-unique solution and low solution precision in the inverse kinematics solution processes of general robots, an improved quantum particle swarm optimization algorithm was proposed. Firstly, the robot kinematics model was established by using the D-H parameter method, and the minimum pose errors at the end of the manipulators were the main optimization goal, and the constraints of the minimum joint angle changes before and after the movement and the smooth and continuous stroke were added, and the objective function was designed. Secondly, an IQPSO algorithm was designed by using the Levy flight strategy to improve the particle update method, nonlinear dynamic adjust the shrinkage and expansion factors, and using the variable weight method to calculate the optimal average position. Then, the simulation and comparison experiments of three algorithms(IQPSO,APSO,QPSO) were carried out by simulating two different solutions of single point pose and continuous trajectory. The results show that the IQPSO algorithm has the advantages of fast convergence speed and high solution accuracy; finally, the IQPSO algorithm was used in the body of the robot arm for physical verification. The results show that the trajectory composed of interpolation points obtained by the IQPSO algorithm is continuous and smooth, which further proves the stability and feasibility of the algorithm in practical motion control.
    Reference | Related Articles | Metrics | Comments0
    Study on Force Model and Surface Integrity of Cylindrical Grinding 18CrNiMo7-6 Steels
    WANG Dong, CHEN Lei, ZHANG Zhipeng
    China Mechanical Engineering    2024, 35 (03): 381-393.   DOI: 10.3969/j.issn.1004-132X.2024.03.001
    Abstract583)      PDF(pc) (8185KB)(523)       Save
     In order to accurately and effectively control the influences of grinding parameters on grinding force and surface integrity, a three-stage grinding force theoretical model was established based on the plastic deformation, indentation theory and shear strain effect between abrasive particles and materials by analytical method. The brown corundum grinding wheels were selected for grinding experiments to explore the effects of grinding parameters on grinding force and the effects of grinding parameters and grinding force on surface integrity. The optimal processing parameters for cylindrical grinding were obtained through orthogonal experiments of cylindrical transverse grinding. The results show that the average prediction errors of normal and tangential grinding forces in the cylindrical grinding force model are 5.56% and 7.08%, respectively. The radial feed speed of the grinding wheel has the greatest impact on grinding force, followed by grinding width, and the influences of workpiece speed and grinding wheel particle size are relatively small. The radial feed speed and grinding width of the grinding wheel have a significant impact on residual stress, and the particle size of the grinding wheel has the greatest impact on surface roughness. As the grinding force increases, the surface roughness value continuously increases, and the residual stress firstly decreases and then increases. The maximum residual stress value along the depth direction firstly increases and then decreases. Within the parameters taken in the experiments, the distribution range of residual stress is basically 20~40 μm. The optimal combination of processing parameters is a radial feed speed of 0.15 mm/min for the grinding wheel, a workpiece speed of 120 r/min, a grinding width of 10 mm, and a grinding wheel particle size of 80.
    Reference | Related Articles | Metrics | Comments0
    Product Architectures Evolution and Their Open Design Strategies
    CHENG Xianfu, ZHANG Zhihong, WANG Chenghui, PAN Yifei
    China Mechanical Engineering    2024, 35 (01): 109-124.   DOI: 10.3969/j.issn.1004-132X.2024.01.011
    Abstract531)      PDF(pc) (2035KB)(501)       Save
    Product architecture represented the arrangements and combinations of physical components. It might promote innovation of product diversity, component sharing, and meet customers personalized needs. Open design might support customers to participate in product development, and open product architecture provided platform strategy for personalized product development. To further study the theory and applications of product architecture, the concept and effect of product architecture were introduced, as well as the characteristics, association and difference between single product architecture, product family architecture and open product architecture were expounded. The evolution processes of product architecture and their internal motivation were analyzed from the aspects of architecture topology, architecture development strategy, architecture organization and management. The concept, connotation, function and mechanism of product architecture were reviewed. The dependence of customers personalized needs, product architecture and enterprises open innovation strategy were discussed, and then open design strategies of product architecture were explored.
    Reference | Related Articles | Metrics | Comments0
    Research Status and Development Trends of Large Wind Turbine Main Shaft Sliding Bearings
    ZHU Caichao1, ZHANG Ronghua1, SONG Chaoshen1, TAN Jianjun1, YANG Liang2
    China Mechanical Engineering    2024, 35 (10): 1711-1721.   DOI: 10.3969/j.issn.1004-132X.2024.10.001
    Abstract1044)      PDF(pc) (4422KB)(490)       Save
    The pace of large wind turbine units was accelerating, and the reliability of core components was increasingly important for wind turbine operations. Sliding bearings had the advantages of high load capacity, long life, easy maintenance, scalability and small size, and they had advantages and great potential for the reliable replacement of wind turbine main bearings key components produced at home. The problems of main shaft rolling bearings in high-power wind turbines and the advantages of using sliding bearings on the main shaft were analyzed herein. The technical methods and application status of wind turbine main shaft sliding bearing design, materials, lubrication, and experimental verification were present in detail, and the existing problems of high-power wind turbine main shaft sliding bearings and future development trends were summarized. It is expected to provide reference for the digital design and industrial development of high-power wind turbine main bearings.
    Reference | Related Articles | Metrics | Comments0
    Research on Dynamic Modeling and Solving Method of Integrated Transmission System under Time-varying Conditions
    ZHANG Dingge, WANG Liyong, LI Le, ZHANG Jinle
    China Mechanical Engineering    2023, 34 (22): 2665-2673.   DOI: 10.3969/j.issn.1004-132X.2023.22.003
    Abstract553)      PDF(pc) (3130KB)(488)       Save
    In order to meet the demands of real time monitoring of load characteristics and the demands of health management of the special vehicle integrated transmission system under actual complex conditions, by using the matrix analysis method and numerical solution method of planetary transmission mechanisms, and taking the real vehicle sensor data as the model input, a dynamic model of integrated transmission system was established to rapidly and continuously solve the transmission output speed and torque under time-varying conditions. The kinematic matrix, differential equation and torque balance equation of the planetary transmission mechanisms were constructed. The fast continuous solution method of the dynamic model under time-varying conditions and the method for solving road load under the conditions of missing road load information were proposed. The calculated transmission output speed and torque were compared with the bench test results under the three typical conditions of launching, shifting and acceleration. The results show that the dynamic model may realize the dynamic simulation calculation of the output characteristic of the integrated transmission under the conditions of missing road load information. It provides support for real-time monitoring, dynamic control and intelligent operation and maintenance of special vehicle integrated transmission systems. 
    Reference | Related Articles | Metrics | Comments0
    Modeling and Experimental Research of Ground Workpiece Surface Topography after Grinding with Structured Grinding Wheels
    YI Jun, YI Tao, CHEN Bing, DENG Hui, ZHOU Wei,
    China Mechanical Engineering    2023, 34 (22): 2711-2720.   DOI: 10.3969/j.issn.1004-132X.2023.22.008
    Abstract574)      PDF(pc) (9016KB)(463)       Save
     The rough surface modeling method was employed to establish the surface topography model of a straight groove structured grinding wheel, considering the influences of structural characteristic parameters on the continuity of the grinding wheel surface through actual measurements. Based on the kinematics relationship between the grinding wheel and workpiece, as well as the trajectory equation of cutting edge, a prediction model for workpiece surface topography after grinding was formulated. Grinding experiments were conducted using both electroplating CBN and brazing CBN straight groove structured grinding wheels. The results show that relative errors between predicted Ra values and experimental ones are below 10%, while relative errors between predicted Rz values and experimental ones are below 12%, thereby validating the accuracy of the prediction model. Furthermore, the influences of various structural parameters on the surface topography of the workpiece were investigated. When the groove width of the grinding wheel remaines constant, an increase in the intermittent ratio of the grinding wheel resultes in an elevation of workpiece surface roughness. Conversely, when the intermittent ratio is held constant, variations in groove width have a minimal effect on workpiece surface roughness. Additionally, it is observed that roughness of the grinding wheel itself is a significant factor determining ground workpiece surface roughness. Among the three characteristic parameters of the grinding wheel surface topography investigated herein, it is observed that the skewness of the grinding wheel surface height exerts the most significant influence on the ground workpiece surface roughness.
    Reference | Related Articles | Metrics | Comments0
    Design and Processing Research of Dynamic Pressure Assisted Non-Newtonian Fluid Polishing Tools
    ZHANG Qicong, JIANG Chen, YE Hui, SHEN Lingxin, JIAO Mengdie
    China Mechanical Engineering    2023, 34 (23): 2805-2811,2823.   DOI: 10.3969/j.issn.1004-132X.2023.23.004
    Abstract471)      PDF(pc) (8987KB)(432)       Save
    To overcome the problems of low and uneven material removal rate when polishing with NNFL, the design and processing research of dynamic pressure assisted non-Newtonian fluid polishing tools(DNNFTs) were carried out. The DNNFT was designed by adding the pressure-controllable center-int to form a dynamic pressure film. The mechanics properties of the filling material Silly-putty were analyzed, numerical simulation of NNFL fixed point polishing was carried out. The influences of liquid supply pressure on the dynamic pressure field, total pressure field and velocity field of liquid film in the processing area of DNNFT were analyzed based on FLUENT. The material removal function models were constructed based on Preston material removal principle. The polishing process experiments were carried out on 304 stainless steel workpieces. It is concluded that the material removal rate and uniformity may be effectively improved by adding the pressure-controllable center-int. The smallest value of surface roughness(Ra=19 nm) and the best material removal rate(2.431 mg/min) are obtained when the liquid pressure is as 0.8 MPa, the rotational speed is as 1200 r/min and the feed rate is as 6 mm/s. The results prove that DNNFT effectively improves the quality and efficiency of polishing, and improves the uniformity of material removal.
    Reference | Related Articles | Metrics | Comments0
    Design of 3K Planetary Gear Reducers with No Backlash
    WANG Weijun, YANG Guilin, DU Qinghao, CHEN Qingying,
    China Mechanical Engineering    2024, 35 (01): 36-44,55.   DOI: 10.3969/j.issn.1004-132X.2024.01.003
    Abstract890)      PDF(pc) (10399KB)(426)       Save
    Due to the presence of clearances in the gearing of 3K planetary gear reducers, transmission clearances were introduced into the transmission chain, resulting in a decrease in transmission accuracy and causing impacts during driving direction changes. By utilizing the characteristics that the carrier did not participate in torque transmission in 3K planetary gear transmission, a flexible planetary carrier was innovatively proposed to eliminate clearances of 3K planetary gear reducers, and the effectiveness of the proposed clearance elimination mechanisms was verified through simulation analysis. Gear matching and efficiency optimization were performed to achieve high forward and backward driving efficiency. Through the development of a prototype and testing of transmission accuracy, hysteresis characteristics, sinusoidal response error, transmission efficiency, and reverse starting torque, the effectiveness of the proposed flexible planetary carrier in eliminating clearances, transmission accuracy improvement, transmission efficiency and reverse transmission performance promoting was verified. 
    Reference | Related Articles | Metrics | Comments0
    Comprehensive Performance Optimization of High Pressure Threaded Plug-in Relief Valves
    CHEN Junxiang, KONG Xiangdong, XU Kelong, AI Chao,
    China Mechanical Engineering    2023, 34 (24): 2909-2919,2926.   DOI: 10.3969/j.issn.1004-132X.2023.24.002
    Abstract554)      PDF(pc) (4914KB)(384)       Save
    In views of the coupling of structural parameters affecting different performance of high-pressure threaded plug-in relief valves, it was difficult to optimize the comprehensive performance, a multi-objective particle swarm optimization algorithm was proposed to optimize the comprehensive performance. Based on the structural characteristics of high-pressure threaded plug-in relief valves, the mathematical models of opening and closing characteristics, pressure regulation deviation and stability were established. Based on the first-order sensitivity analysis of the influences of structural parameters on the dynamic response, according to the mapping relationship between structure and performance, with the opening rate, pressure regulation deviation, stability and dynamic response performance improvement as the optimization objectives and coupling structure parameters as variables, a comprehensive performance optimization model was established, and the optimal solution of coupling structural parameters was obtained in the form of Pareto set by particle swarm optimization algorithm. The experimental results show that after optimization, the pressure oscillation of the high pressure threaded plug-in relief valves is reduced by 22.7%, the opening rate is increased by 1.5%, the pressure flow gradient is reduced by 14.58%, the pressure overreach in front of the valves is reduced by 14.1%, the response time is shortened by 9.52%.
    Reference | Related Articles | Metrics | Comments0
    An Evaluation Method for Tooth Surface Load Capacity of Polymer Gears Based on Nominal Gear Equivalent Load
    HU Xinlei, LIU Huaiju, WEI Peitang, LU Zehua, LIAO Changjun, ZHU Jiazhan
    China Mechanical Engineering    2023, 34 (24): 2927-2935.   DOI: 10.3969/j.issn.1004-132X.2023.24.004
    Abstract527)      PDF(pc) (6709KB)(376)       Save
    The current evaluation methods for the tooth surface load capacity of polymer gears still rely on the methods for metal gears, which did not comprehensively consider the influences of material type, lubrication condition and stress of the polymer gears. This would lead to significant reliance on engineering experience for material selection, strength design and loading capacity evaluation in practical engineering applications. Therefore, a polymer gear tooth surface load capacity evaluation method was proposed based on the nominal gear equivalent load. Over 169 sets of data and more than 6000 hours of durability tests on polymer gears were obtained, considering different lubrication conditions, gear materials, and machining methods. The results show that oil lubrication may significantly improve the tooth surface load capacity of plastic gears, and the tooth surface load capacity of PEEK(polyether ether ketone) gears is more than 30% higher than that of POM(polyoxymethylene) and PA66(polyamide) gears under oil lubrication, which provides an evaluation method and basic data support for active design and transmission power applications of polymer gears.
    Reference | Related Articles | Metrics | Comments0
    Research on Energy Transfer Model and Optimisation of Operating Parameters of Vibratory Rollers
    HUI Jizhuang, LUO Wei, ZHANG Zeyu, ZHANG Jun, WANG Jie
    China Mechanical Engineering    2024, 35 (03): 541-547.   DOI: 10.3969/j.issn.1004-132X.2024.03.016
    Abstract429)      PDF(pc) (1996KB)(369)       Save
     In order to improve the compaction quality of vibratory rollers, the energy transfer model of vibratory rollers and the optimisation of operating parameters were studied. Firstly, the system vibration dynamics model of “wheel-compacted material” was established based on the U-K equation, and the energy transfer model of vibratory roller was proposed in combination with energy conservation.Then, the vibration frequency and compaction speed were taken as the optimal working parameters to construct the optimisation model of road compaction quality.Finally, the feasibility and effectiveness of the proposed method were proved through case verification. The results show that: the ratio between the working frequency and the intrinsic frequency of the compacted material is kept within the range of 2~2 to avoid the effect of resonance.The initial stage of low-speed rolling, and after the material properties were stabilised, the rolling speed may be increased to ensure efficient compaction, which results in the vibration frequency in the range of 21.8~27 Hz and the compaction speed in the range of 2.36~2.91 km/s, to achieve the optimal compaction effectiveness. The proposed energy transfer model and operation parameter optimisation model lay a foundation for guaranteeing the compaction quality of vibratory rollers and provide a reference for improving the compaction quality and efficiency of vibratory rollers.
    Reference | Related Articles | Metrics | Comments0
    Effects of Tool Wear on Milling Surface Integrity and Fatigue Properties of Allvac 718Plus Superalloy
    GOU Ruijie, ZHANG Xiaofeng, ZHANG Hongbin, YAO Jun, LI Xun
    China Mechanical Engineering    2023, 34 (24): 2920-2926.   DOI: 10.3969/j.issn.1004-132X.2023.24.003
    Abstract468)      PDF(pc) (4539KB)(360)       Save
    Based on the premise of Allvac 718Plus superalloy milling tool wear law, the influence rules of tool wear on the indicators of fine milled surface integrity were studied,and combined with specific fatigue performance tests of specimens, the influence rules and mechanism of tool wear on the fatigue performance of specimens were analyzed. It is obtained that the control range of flank face tool wear under the parameters of Allvac 718Plus fine milling is less than 0.15 mm, and the main influencing factors on fatigue performance of the specimens are also obtained. The relevant research results provide a reference for controlling the surface integrity and tool wear of Allvac 718Plus specimens in fine machining.
    Reference | Related Articles | Metrics | Comments0
    A Structural Reliability Calculation Method Based on Adaptive Kriging Ensemble Model
    GAO Jin, CUI Haibing, FAN Tao, LI Ang, DU Zunfeng
    China Mechanical Engineering    2024, 35 (01): 83-92.   DOI: 10.3969/j.issn.1004-132X.2024.01.008
    Abstract657)      PDF(pc) (4853KB)(358)       Save
     The reliability analysis results of complex structures based on the Kriging model were highly dependent on the fitting accuracy of the Kriging model. In the constructing processes of the Kriging model, the selection of different correlation and regression functions affected the accuracy of the model. In order to solve the impacts of model uncertainty on the reliability analysis results, while considering computational efficiency and accuracy, based on the Kriging model and Monte Carlo simulation(MCS) method, a structural reliability calculation method combining adaptive ensemble strategy and active learning function was proposed. Considering the modeling uncertainty of Kriging models, combined with multiple Kriging models, this methed constructed an active learning function that comprehensively considered sample point contribution and sample point distance. The ensemble Kriging model was iteratively updated through the active learning function until the convergence conditions were satisfied. Finally the structural reliability analysis was carried out by the constructed ensemble Kriging model and MCS method. The validity of the proposed method was verified by numerical and engineering examples, and the results show that the proposed method is more robust than other major methods, and the computational efficiency is higher while ensuring the computational accuracy.
    Reference | Related Articles | Metrics | Comments0
    Review on Management at Mechanical Design and Manufacturing Discipline of National Natural Science Foundation of China in 2023
    YE Xin, HUANG Zhiquan, ZHANG Junhui,
    China Mechanical Engineering    2024, 35 (04): 571-579.   DOI: 10.3969/j.issn.1004-132X.2024.04.001
    Abstract581)      PDF(pc) (8141KB)(348)       Save
     The applications, evaluations, and funding of several types of projects that were classified into the talent and exploratory funding categories at mechanical design and manufacturing discipline (division Ⅱ of engineering science) of the National Natural Science Foundation of China in 2023, as well as the research progresses and findings of the executing and finished projects were reviewed. Specific measures of mechanical design and manufacturing discipline were illustrated, such as the reform of scientific fund, talent cultivation, and future research. Finally, a short prospect of the work in 2024 was introduced.
    Reference | Related Articles | Metrics | Comments0
    Visual Detection of Subsurface Corrosions in Ferromagnetic Metal Plates Using Pulsed Eddy Current Based on Dual-sensor Differential Mechanism
    WANG Jin1, LI Yong1, SU Bingjie1, GAO Wenlong1, XIANG Yi1, 2, LIU Zhengshuai1, CHEN Zhenmao1
    China Mechanical Engineering    2025, 36 (03): 381-390.   DOI: 10.3969/j.issn.1004-132X.2025.03.001
    Abstract362)      PDF(pc) (17686KB)(345)       Save
    A pulse eddy current visual detection method was proposed based on a dual-sensor differential mechanism for subsurface corrosions in ferromagnetic metal plates. In this method, a dual-sensor differential probe was used to pick up the pulsed eddy current testing signals, and the slope of the logarithmic curve along the falling edge of the testing signals and the peak value of the normalized differential signals were extracted as signal features, which were used for visual detection of defects of different sizes. Through simulation and experimental research, the correlation laws between the proposed signal features and the sizes of defects were established, and it is verified that the dual-sensor differential probe has the advantages of reducing noise interference and improving the detection sensitivity compared with traditional single-sensor probes. In addition, a method was proposed to fuse the two signal features, and the results indicate that the defect images using fused signal features have a higher image signal-to-noise ratio. The research method proposed herein provides an effective and reliable solution for the visual detection of subsurface corrosions in ferromagnetic metal plates.
    Reference | Related Articles | Metrics | Comments0
    Design of Lane Keeping Assist Systems Based on Improved Preview Control Model
    LIANG Yongbin, FU Guang, LIN Zhigui, HE Zhicheng, ZHANG Jialuo, CHEN Tao
    China Mechanical Engineering    2024, 35 (03): 548-558.   DOI: 10.3969/j.issn.1004-132X.2024.03.017
    Abstract506)      PDF(pc) (8767KB)(342)       Save
    To address the issues of low robustness, consistency in vehicle manufacturing, and severe road surface interference in LKA system of torque control, a LKA system was designed based on angle control by using neural network technology, Autofix algorithm, and preview feedback control theory, through expected trajectory decision-making and following PID control algorithm. A hardware-in-the-loop simulation test platform was built to verify the effectiveness and accuracy of the design of the angle based lane protection systems through virtual simulation based on Carsim/Veristand/ MATLAB. Based on GB/T 39323—2020, CN-CAP—2021, Euro-NCAP—2022 and the testing requirements of the car retention systems based on real-road commissioning and user concern scenarios, the simulation and comparison with real-road scenarios show that the angle-controlled LKA system has better lane keeping capability, stability, adaptability and robustness than that of the torque-controlled LKA system in the same usage scenarios.
    Reference | Related Articles | Metrics | Comments0
    Matching Design of Distributed Propulsion Systems for Hydrogen-Lithium Batteries Powered Commuter Aircrafts
    WANG Yu, WU Tingjia, LI Xiang, YU Xiongqing,
    China Mechanical Engineering    2024, 35 (01): 27-35.   DOI: 10.3969/j.issn.1004-132X.2024.01.002
    Abstract552)      PDF(pc) (6663KB)(341)       Save
    Aiming at the overall design parameters and mission profile requirements of commuter aircrafts, according to the hydrogen-lithium propulsion system architecture scheme, the propulsion system parameter matching method and energy dynamic balance management strategy were proposed. A 19-seat commuter aircraft was used to select and manage the power plant and reserve energy. According to the selected distributed aerodynamic layout scheme, then the effects of propeller rotation directions on aircraft aerodynamic characteristics were analyzed with full factorial design of experiments, and the optimum propeller rotation direction configuration for aircraft cruise states was obtained.
    Reference | Related Articles | Metrics | Comments0
    Design of Experimental Device for Sealing Performance of Hydraulic Pump Plungers
    LUO Longjun, HE Xiaofeng, LIU Xun, ZHANG Qiaxuan, HUANG Hewen
    China Mechanical Engineering    2024, 35 (02): 229-235.   DOI: 10.3969/j.issn.1004-132X.2024.02.006
    Abstract377)      PDF(pc) (4818KB)(339)       Save
    In order to solve the sealing reliability and selective design problems of the plungers and cylinder liners of oil-water separated plunger pump, a plunger sealing performance experimental device and the loading system were developed to simulate the actual operating conditions of the hydraulic plunger pump, and the dynamic balance design of the experimental device was carried out. The simulation model of the loading system for the experimental device was established, and then a reasonable loading method was determined through simulation and comparison. The loading test and stability test of the experimental device show that the operation of the experimental device is stable and reliable, and the volumetric efficiency is within a reasonable range.
    Reference | Related Articles | Metrics | Comments0
    Dynamics Simulation Data Driven Domain Adaptive Intelligent Fault Diagnosis
    YU Shubo, LIU Zhansheng, ZHAO Chen
    China Mechanical Engineering    2023, 34 (23): 2832-2841.   DOI: 10.3969/j.issn.1004-132X.2023.23.007
    Abstract539)      PDF(pc) (7710KB)(336)       Save
     High-quality labeled data was a crucial prerequisite for the effectiveness of deep learning-based fault diagnosis methods. However, obtaining a substantial number of industrial labeled fault cases was challenging, which led the models generalization ability weak. A novel domain adaptive intelligent diagnosis method driven by dynamics simulation data was proposed to address the above issue. This method considered the fundamental disparity between simulation data and actual data, and introduced a feature separation network for domain adaptation in diagnostic modeling. Based upon traditional domain adaptation models, a unique feature extractor that was specific to the target domain was incorporated to explicitly separate environmental noises present in actual data. This enhancement improved fault feature representation and clustering capabilities through other features that remain invariant across domains. Furthermore, a novel training strategy was proposed that leveraged diagnostic results obtained from the shared feature extractor to iteratively update the model parameters of the unique feature extractor, thereby enhancing training stability even further. The proposed method was evaluated using the bearing dataset from Case Western Reserve University, demonstrating improved feature extraction and clustering capabilities compared to other transfer methods for comparison, as evidenced by enhanced performance and diagnostic accuracy. Additionally, the hyper-parameter sensitivity was analyzed empirically. 
    Reference | Related Articles | Metrics | Comments0
    Research on Thermo-mechanical Fatigue Life Prediction Model of Ni-base Superalloy
    CUI Haitao, QIAN Chunhua
    China Mechanical Engineering    2024, 35 (01): 67-73,82.   DOI: 10.3969/j.issn.1004-132X.2024.01.006
    Abstract601)      PDF(pc) (2443KB)(330)       Save
    In phase TMF tests on nickel-based high-temperature alloy GH4169, a commonly used material for engine hot end components, under conditions of 200450 ℃ and 400650 ℃ is conducted. Considering the micro damage strain energy of polycrystalline materials in the elastic stages under the condition of TMF, a TMF life prediction model suitable for polycrystalline materials was proposed, model parameters were determined by combining the TMF test data. Three superalloys, GH4169, IN718, DD8, were used to evaluate the TMF life prediction ability of this model. The prediction accuracy of the life model is higher than that of the Manson-Coffin model and Ostergen model commonly used for TMF life prediction.
    Reference | Related Articles | Metrics | Comments0
    China Mechanical Engineering    2024, 35 (01): 0-.  
    Abstract268)      PDF(pc) (339KB)(328)       Save
    Related Articles | Metrics | Comments0
    Study on Vibration and Fatigue of Distributed Connection Structures of Reusable Aircrafts
    SHEN Minmin, SHI Rui, GUO Pengfei, YANG Yang, YANG Xiaodong, YANG Jihou
    China Mechanical Engineering    2024, 35 (01): 45-55.   DOI: 10.3969/j.issn.1004-132X.2024.01.004
    Abstract485)      PDF(pc) (9287KB)(325)       Save
    Accurate calculation of the vibration characteristics and fatigue life of the distributed connection structures between reusable spacecraft and engines was crucial for ensuring the safe operations of aerospace transportation systems. Focusing on the distributed connection structures, the feasibility of experimental validation for finite element simulation methods was demonstrated. The vibration characteristics of the distributed connection structures were explored in both of the time and frequency domains, and the fatigue lives of the structures were calculated under different operating conditions. The findings reveal a commendable concordance between the finite element results of the hysteresis curve for the connection structures and experimental observations. Under cyclic loading at different excitation frequencies, the connection bolts manifest stress increments or decrements, indicative of fatigue effects. The distributed connection structures elicit significantly heightened responses at the 1st and 5th natural frequencies. Decreasing the excitation magnitude substantially augments the fatigue lives of the connection structures, and an escalation in bolt pre-tightening forces is found to enhance fatigue lives as well. However, an increase in excitation frequency only marginally diminishes the operational lifespans, while the cyclic lifespans persist within the same order of magnitude. Furthermore, following the introduction to thermal and creep effects, the distributed connection structures may withstand a maximum of only five thermal cycling loads.
    Reference | Related Articles | Metrics | Comments0
    Integrated Casting Triangular Beam Lightweight Improving with Multi-performance Constraints of Body Systems
    SU Yonglei, ZHANG Zhifei
    China Mechanical Engineering    2024, 35 (04): 691-699.   DOI: 10.3969/j.issn.1004-132X.2024.04.012
    Abstract486)      PDF(pc) (6363KB)(324)       Save
     An optimization method of integrated casting structures was constructed systematically, and based on the super-element model of body system, body casting part lightweight improving with multi-performance constraints was realized. Firstly, complex body systems were reduced, the sub-system division principle and method were proposed for continuous body structure. Super-element reduction of the sub-system was conducted to ensure analysis accuracy and improve calculation efficiency, laying the foundation for rapid optimization. Secondly, performances of casting structures and body systems were considered simultaneously, the compromise programming methods were used to normalize static and dynamic sub-targets and construct the comprehensive objective function, weight coefficients of sub-targets were obtained by analytic hierarchy process(AHP), and then multi-model topology optimization was carried out to determine position distribution of reinforcements. Furthermore, designability and manufacturability were considered simultaneously, parametric definition of variable thickness drawing surface of casting structure was carried out, manufacturing constraints were applied during optimization processes, and then thickness parameter design was completed based on combined surrogate model. The results show that, under the premise of ensuring the analysis accuracy, reduced body system models improve computing efficiency greatly, and save 97.3% of computing resources. Casting triangular beam lightweight may be achieved while improving related performance by conducting structure optimization, which indicates correctness and practicability of the proposed method. 
    Reference | Related Articles | Metrics | Comments0
    Calculation Method of Time-varying Meshing Stiffness of Small Module Gear Transmissions
    HU Bo, AN Jinyun, YIN Lairong, ZHOU Changjiang
    China Mechanical Engineering    2024, 35 (01): 74-82.   DOI: 10.3969/j.issn.1004-132X.2024.01.007
    Abstract556)      PDF(pc) (10849KB)(314)       Save
    Due to the small center distance, the dynamic performance of small modulus gear transmissions was very sensitive to the center distance errors. In addition, the intermediate gears were often designed to rotate at high speed on the fixed shaft, and there were clearances between the gear center hole and the shaft. Therefore, the calculation model of the gear mesh characteristic parameters and time-varying mesh stiffness under the influences of the center distance errors and the shaft hole fit clearances was established, and the influence laws of the two factors mentioned on the mesh stiffness were investigated. The results show that the center distance errors will change the contact degree and meshing stiffness of the gear pairs. The shaft hole clearance causes the actual center distance to fluctuate periodically around the theoretical center distance, which leads to the coexistence of the strengthening and weakening regions of the meshing stiffness in the whole cycle. The influences of center distance errors and shaft hole fit clearances both superimposed and weakened each other in different angle ranges, resulting in the difference in meshing stiffness of each gear tooth, and the risk of inducing greater vibration and different noise.
    Reference | Related Articles | Metrics | Comments0
    Analysis for Aero -elastic Characteristics of Prop-Rotor in Hover with a Swept Tip
    HUANG Wei, CHI Cheng
    China Mechanical Engineering    2024, 35 (02): 191-200.   DOI: 10.3969/j.issn.1004-132X.2024.02.001
    Abstract397)      PDF(pc) (9640KB)(314)       Save
    The issues of significant stress and strain concentration within the prop-rotor blades caused by large negative twist and swept tips were addressed herein. By 3D structural dynamics model, rotor aerodynamics model, and rotor trim methods, a comprehensive model of composite prop-rotor was developed, and the aeroelastic loads of composite prop-rotor were analyzed, and the accuracy of the synthesis model was validated through hover experiments. The analysis of aero-elastic characteristics was performed for rotor blades with zero twist, large negative twist, and large negative twist with swept tips. The results indicate that the large negative twist enlarges the stress concentration area, while the swept tip makes the stress concentration at the swept transition area larger and the degree of concentration worsens. 
    Reference | Related Articles | Metrics | Comments0
    Classification Test of Tire Tread Wear of Passenger Cars Based on In-wheel Acceleration
    TAO Liang, TANG Yu, QI Wenjie, ZHANG Dashan, LU Rui, ZHANG Xiaolong
    China Mechanical Engineering    2023, 34 (22): 2737-2745.   DOI: 10.3969/j.issn.1004-132X.2023.22.010
    Abstract569)      PDF(pc) (8588KB)(314)       Save
    In light of the issue that the tread depth of passenger car tires was shallow and the conventional identification of wear characteristics were not obvious based on acceleration time-domain signals. This paper aimed to explore the classification and estimation of tire wear through the analysis of frequency-domain features of internal tire acceleration. Firstly, an intelligent tire test system was built by self-developed special rim assembly and data collector, and a three-axis accelerometer was arranged in the tire inner liner. The acceleration values were obtained by wired method, and the sampling frequency was 50 kHz. Secondly, based on the built test system, the typical tire pure rolling test was carried out on the Flat Trac bench, and the data was analyzed to clarify the parameters of the classification algorithm and construct the data set. The test tires included new tire, semi-grinding tire and full-grinding tire. The data analyses show that the circumferential acceleration Ax and radial acceleration Az of tires with different wear degrees are significantly different in the frequency domain of 5 kHz. Therefore, the vibration amplitude of Ax and Az in the frequency domain of 5 kHz was extracted at an interval of 10 Hz as the feature point, and the frequency domain data sets FDAx and FDAz were established respectively with vertical load, speed and tire pressure. Finally, the random forest algorithm was used to train and predict the two data sets respectively. When the number of decision trees and the minimum number of leaves are 20 and 20 respectively, the model classification effectivenes is the best. The results show that the average classification accuracy of the frequency domain data set FDAz is 95.1543%, which is higher than that of the data set FDAx. Compared with the time domain data sets TDAx and TDAz constructed by extracting Ax and Az time domain features from the same experimental data, the classification accuracy is increased by 16.18% and 10.08% respectively. At the same time, the feature values of the FDAz data set are optimized to obtain the optimal model classification accuracy and real-time performance when the feature frequency band and the number of feature points are within 1000 Hz and 100, respectively. The research shows that it is feasible to identify the degree of tire wear based on the frequency domain signals of the acceleration in the tire, which provides an effective means for the identification of the degree of tire wear of passenger cars.
    Reference | Related Articles | Metrics | Comments0
    Fractional-order Feedback Control Method for PMLSMs Based on Closed-loop Identification Model
    ZHONG Yongbin, GAO Jian, FENG Fuyuan, ZHANG Lanyu,
    China Mechanical Engineering    2023, 34 (23): 2773-2780,2793.   DOI: 10.3969/j.issn.1004-132X.2023.23.001
    Abstract466)      PDF(pc) (7146KB)(306)       Save
     In order to improve the tracking accuracy of PMLSMs, a fractional-order feedback control method was proposed based on closed-loop identification model. By precisely adjusting the error amplitude characteristics of the feedback control system in a specific fractional-order form, the following errors of PMLSMs might be effectively suppressed. A closed-loop identification model was derived for the PMLSM and the parameter selection method of the fractional-order lead-lag compensator was determined based on analysis of the error amplitude characteristics. With the properly defined fractional-order parameters, the fractional-order feedback control system might accurately describe the frequency-domain characteristics of the PMLSM, and the identification accuracy and control performance of the PMLSM might thus be improved. The proposed method  was experimentally validated on a PMLSM gantry motion platform through identification methods, tracking experiments with different motion planning, and circular trajectory motion experiments. The experiments on system closed-loop identification and motion tracking with different plannings were performed. The experimental results show that the closed-loop identification method may effectively suppress the influences of external interferences on the identification signals, and the closed-loop identification model is accurate for the control system, the proposed fractional-order feedback control method may greatly reduce the tracking errors of the PMLSMs, and compared to the PID control method, the proposed control method may reduce the root mean square error (RMSE) tracking errors by at least 82.47% under different motion scenarios. The experimental results demonstrate the effectiveness of the proposed method in improving the tracking accuracy of PMLSMs. 
    Reference | Related Articles | Metrics | Comments0
    Research on Active Power Control of Hydraulic Wind Turbines Based on Feedback Linearization and Nonlinear Disturbance Compensation
    CHEN Lijuan, WU Die, GAO Wei, WEI Longzheng, CAO Shengwei, AI Chao, LI Jingbin
    China Mechanical Engineering    2023, 34 (23): 2889-2897.   DOI: 10.3969/j.issn.1004-132X.2023.23.013
    Abstract482)      PDF(pc) (6922KB)(305)       Save
     The hydraulic wind turbine could not directly generate electricity after being connected to the grid, it was necessary to control the active power. The wind energy had randomness and volatility. The system had time-varying and nonlinear characteristics, and it was necessary to solve the accurate control of the active power of the fans under external disturbances. The nonlinear problem of the hydraulic main drive system was solved by feedback linearization. The nonlinear disturbance observer was used to quickly and accurately observe the influences of external disturbances on the output power of the system. An active power compensation controller under mismatched disturbances was proposed to accurately compensate the influences of disturbances on the output power of the system, and the active power control strategies of the hydraulic wind turbine were obtained. Based on the semi-physical simulation experimental platform of 30 kV·A hydraulic wind turbine, the output active power of the unit may accurately follow the target speed changes. The absolute error of active power is as ±0.05 kW, and the steady-state errors are within the range of 3%~5%. 
    Reference | Related Articles | Metrics | Comments0
    Research on Two-level Fusion Strategy of Unmanned Driving Perception Information Target-decision under Tunnel Environments
    WANG Maosen, BAO Jiusheng, XIE Houkang, LIU Tonggang, YIN Yan, ZHANG Quanli
    China Mechanical Engineering    2024, 35 (03): 427-437.   DOI: 10.3969/j.issn.1004-132X.2024.03.005
    Abstract494)      PDF(pc) (4400KB)(305)       Save
    Based on the special driving environment in the tunnel and the perception requirements of unmanned driving, appropriate sensors and hardware were chosen to build a test vehicle and a perception system of multi-sensor fusion of millimeter-wave radar and camera. A two-level information fusion algorithm of “target-decision” was proposed based on YOLOv4 target-level information fusion algorithm and improved D-S evidence theory. Finally, a verification test of perception information two-level fusion was carried out in the urban road tunnel environments. The results show that in the tunnel environments, compared with the single camera or the millimeter-wave radar sensing results, the target-level fusion result based on the association of the camera and the millimeter-wave radar sensor to perceive the ROI area may improve the recognition accuracy by 9.51%, making up for the shortcomings of a single sensor in the tunnel environment perception technology. Based on the target-level fusion perception results, using the improved D-S evidence theory algorithm to perform decision-level fusion, compared with the single target-level fusion results, the false detection rate is reduced by 3.61%, which significantly improves detection accuracy. By adopting the multi-sensor sensing information target-decision-making two-level fusion strategy, it may meet the reliable sensing requirements of unmanned vehicles in the special tunnel environments, and provide theoretical and technical support for promoting the applications of unmanned controlled technology.
    Reference | Related Articles | Metrics | Comments0
    Design and Experimental Verification of Unilateral Double-needle Double-thread Oscillating Stitching Trajectories
    GAO Ziqiao, DONG Jiuzhi, CHEN Yunjun, JIANG Xiuming,
    China Mechanical Engineering    2024, 35 (01): 102-108.   DOI: 10.3969/j.issn.1004-132X.2024.01.010
    Abstract430)      PDF(pc) (6351KB)(302)       Save
    Due to a thickness of more than 3 mm could not be sewed using the single-sided double-needle double-thread stitching head insertion mechanism, an asymmetrical 8-shaped motion trajectory was proposed and the motion trajectory of the needle insertion mechanisms was designed. Firstly, the dimensions of various components of the oscillating insertion mechanisms were determined based on the kinematic analysis of the single-sided double-needle double-thread stitching processes. Then, a mechanism model was constructed in ADAMS and a trajectory analysis was performed. Finally, stitching experiments were conducted using the prototype. The results show that the designed stitching mechanisms may increase the actual stitching thickness from less than 3 mm to 8 mm and form a stable loop during the stitching processes, confirming the reliability of the asymmetric 8-shaped stitching technique and the oscillating insertion mechanisms.
    Reference | Related Articles | Metrics | Comments0
    Optimization of Process Parameters in Process Manufacturing Based on Ensemble Learning and Improved Particle Swarm Optimization Algorithm
    LIU Xiaobao, YAN Qingxiu, YI Bin, YAO Tingqiang, GU Wenjuan
    China Mechanical Engineering    2023, 34 (23): 2842-2853.   DOI: 10.3969/j.issn.1004-132X.2023.23.008
    Abstract1026)      PDF(pc) (12172KB)(299)       Save
     Considering the complexity of technological processes, the serious coupling between multiple processes and the difficulties in optimizing process parameters during the process manufacturing, a multi-process technological parameter fusion optimization method was proposed based on LSTM neural network, XGBoost algorithm and IPSO algorithm. A data preprocessing model was established based on LSTM neural network, and the time series characteristics of processing data were extracted through LSTM neural network, which realized the processing of outlier in process data. And a PSO-XGBoost quality prediction model was constructed by fitting the nonlinear relationship between processing parameters and quality indexes with XGBoost and combining with particle swarm optimization algorithm. Then the output of the quality prediction model was taken as the fitness, and the improved particle swarm algorithm was used for trolling the global optimal processing parameters, which realized the fusion optimization of the quality of process manufacturing. A process production line of an enterprise was taken as an example to verify the effectiveness of the multi-process technological parameter fusion optimization model. 
    Reference | Related Articles | Metrics | Comments0
    A Method for Identifying and Predicting Energy Consumption of Machine Tools by Combining Integrated Models and Deep Learning
    XIE Yang, DAI Yiqun, ZHANG Chaoyong, LIU Jinfeng
    China Mechanical Engineering    2023, 34 (24): 2963-2974.   DOI: 10.3969/j.issn.1004-132X.2023.24.008
    Abstract649)      PDF(pc) (9506KB)(277)       Save
    In response to the problems of multi-source influences, high quality feature extraction and selection, complexity and nonlinearity in identification methods for energy consumption processes, a method for identifying and predicting energy consumption of machine tools was proposed by combining integrated models and deep learning. Taking CNC milling as an example, an energy consumption model was established based on different cutting periods, and signals were preprocessed by wavelet transform. The preprocessed signals were used to train and predict the energy consumption of the model combining RF and LSTM neural network(RF-LSTM model). Meanwhile, the RF was used to identify the cutting stages and realize the energy consumption classification prediction. The effectiveness and superiority of the proposed method were demonstrated through practical cases, and the RF-LSTM model was used to compare with the other four schemes, which verify that this recognition method may accurately predict different operating states and energy consumption of the machine tools.
    Reference | Related Articles | Metrics | Comments0
    A Non-uniform Damage Accumulation Model Considering Load Interactions
    WU Zhifeng, GAO Jianxiong, XU Rongxia, ZHU Pengnian
    China Mechanical Engineering    2023, 34 (22): 2659-2664,2673.   DOI: 10.3969/j.issn.1004-132X.2023.22.002
    Abstract509)      PDF(pc) (2724KB)(274)       Save
     In order to study the evolution law of fatigue damage of metal components, a non-uniform damage accumulation model and life prediction theory were established considering the interaction of loads. First, a non-uniform fatigue damage model was proposed based on residual life under constant amplitude loading. Secondly, the loading sequence effect was expounded, and it was proved that the proposed load loading sequence effect might be considered in the non-uniform damage model. Then, the interaction among loads was verified, and it was proposed that there was mutual influence between adjacent two-level loads, the load interaction factor was defined and introduced, and a new equivalent damage model was established. Finally, combining the non-uniform damage model with the new equivalent damage model, a non-uniform damage model was constructed under multi-level variable amplitude loads. Life prediction was carried out with the test data of 30NiCrMoV12 steel and Al-2024-T45 alloy under two-level loading. By comparing with various models, it was verified that the proposed model may predict fatigue life well. The proposed model has a certain reference value for the damage evolution law of metals. 
    Reference | Related Articles | Metrics | Comments0
    Contact Fatigue Performance of PEEK under Oil-injected Lubrication
    WU Ruo, WEI Peitang, XIE Huaijie, BIAN Jiang, LU Zehua, LIU Huaiju
    China Mechanical Engineering    2024, 35 (02): 221-228.   DOI: 10.3969/j.issn.1004-132X.2024.02.005
    Abstract458)      PDF(pc) (12856KB)(273)       Save
    PEEK was a high-strength, heat-resistant engineering polymer, but the absence of basic data of PEEK contact fatigue restricted the reliable and long-life applications under heavy-duty conditions. PEEK rolling contact fatigue tests and gear contact fatigue tests under oil injection lubrication were conducted herein, and the S-N curves were obtained. It is found that the PEEK rolling contact fatigue limit is 14% higher than gear contact fatigue limit, and the rolling contact fatigue life of rollers under the contact pressure of 135 MPa is 58% higher than gear fatigue life. And then, the conversion formula of PEEK roller-gear contact fatigue life was further proposed.
    Reference | Related Articles | Metrics | Comments0
    Thermo-mechanical Fatigue Life Prediction and Optimization Design Method Based on Equivalent Component Model of Cylinder Head
    YANG Wenjun, PANG Jianchao, KANG Xin, WANG Lei, LI Sicheng, ZHANG Zhefeng
    China Mechanical Engineering    2023, 34 (24): 3004-3014.   DOI: 10.3969/j.issn.1004-132X.2023.24.012
    Abstract485)      PDF(pc) (9409KB)(270)       Save
    In order to predict the fatigue life of cylinder heads of internal combustion engines more efficiently and simply and further to develop the optimization design, a thermo-mechanical fatigue life prediction and optimization design method was proposed based on the equivalent component model of cylinder heads. Numerical modeling of simulated components was achieved successfully by geometric characteristics of flame deck. Then applying the Sehitoglu theory, the effects of service loads on the thermo-mechanical fatigue damage were investigated. The results indicate that working speed has the most significant effect on the thermo-mechanical fatigue life, and mechanical damage is much dominant among the three damage types. Finally, based on the simulated components and response surface test design method, the optimization design of cylinder head components was carried out. The results show that the maximum stress is decreased by 7% at the region of nose bridge, fatigue life reaches 6.7×104 cycles, and the fatigue damage characteristics of cylinder heads are improved, which may provide a theoretical basis for the thermo-mechanical fatigue life prediction and structural optimization of cylinder heads under service conditions.
    Reference | Related Articles | Metrics | Comments0
    Numerical Analysis Method and Test for Contact Stress of Cycloidal Gear in RV Reducer
    HUANG Xiangmao
    China Mechanical Engineering    2023, 34 (24): 3015-3023.   DOI: 10.3969/j.issn.1004-132X.2023.24.013
    Abstract634)      PDF(pc) (8857KB)(268)       Save
    The effective contact area and circumferential load distribution of cycloid gear tooth surfaces under specific loads were calculated by taking into account the elastic deformations and backlash of cycloid tooth surfaces. A mathematical model of contact stress in the tooth width direction of cycloidal gears was established by using force balance equation and deformation coordination equation, and the calculation procedure and flow chart were given. The mathematical model was a nonlinear equation set, by solving the nonlinear equations, the stress distribution and contact width in the tooth width direction of cycloidal gears were obtained. The mathematical model of contact stress and computational procedures were given to simulate the contact tooth width and contact stress distribution of cycloidal gear under ideal conditions and alignment errors. And the correctness and feasibility of the proposed method were verified by combined with testing and simulation results.
    Reference | Related Articles | Metrics | Comments0