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    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
    Abstract554)      PDF(pc) (50387KB)(669)       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.
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    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
    Abstract411)      PDF(pc) (3896KB)(440)       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.
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    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
    Abstract206)      PDF(pc) (9652KB)(440)       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.
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    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
    Abstract359)      PDF(pc) (5000KB)(428)       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.
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    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
    Abstract217)      PDF(pc) (8185KB)(340)       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.
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    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
    Abstract273)      PDF(pc) (9016KB)(277)       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.
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    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
    Abstract348)      PDF(pc) (10399KB)(274)       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. 
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    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
    Abstract214)      PDF(pc) (10849KB)(256)       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.
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    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
    Abstract262)      PDF(pc) (4539KB)(255)       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.
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    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
    Abstract176)      PDF(pc) (2035KB)(243)       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.
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    Analysis of Causes for Rail Corrugation on Steel Spring Floating Slab Tracks of Metro Small Radius Curves
    WANG Zhiqiang, LEI Zhenyu
    China Mechanical Engineering    2023, 34 (24): 2899-2908.   DOI: 10.3969/j.issn.1004-132X.2023.24.001
    Abstract312)      PDF(pc) (10660KB)(235)       Save
     In order to explore the causes of corrugation on the steel spring floating slab track with the small radius curves of metro, the formation processes of rail corrugation were explained from the perspective of wheel-rail stick-slip vibrations. Firstly, according to the basic situation of the line, a three-dimensional finite element model of wheelset-floating slab track was established. Then, the wheel-rail contact stick-slip features and rail longitudinal wear characteristics were analyzed using the above model to quantify the occurrence trend of corrugation. Finally, the relationship between the natural vibration properties of wheel-rail system and the formation of corrugation was studied based on the complex modal theory. The results show that the stick-slip distribution of the inside wheel-rail interface changes periodically during the operation of the wheelset, indicating that the inside wheel-rail system has experienced periodic stick-slip vibrations, which may lead to periodic wavy wear on the inner rails, and finally form rail corrugation; the stick-slip distribution of the outside wheel-rail interface has not changed significantly in general, which indicates that there is no stick-slip vibrations in the outside wheel-rail systems, so it is not easy to form rail corrugation. In the longitudinal direction of the rail, the slip of the inner rail is significantly greater than that of the outer rail, illustrating that the longitudinal wear of the inner rail is greater; in the transverse direction of the rail, there is little difference between the slip of inner and outer rails, illustrating that the transverse wear of inner and outer rails is similar. The distribution of longitudinal and transverse slip nephograms of inner and outer rails shows a certain degree of periodicity, especially the longitudinal slip nephogram of the inner rail, with a wavelength of 28 mm close to the measured corrugation wavelength of 25 mm, which is consistent with the periodic characteristics of the contact stick-slip state of the inside wheel-rail interface, and further shows that the inner rail is more prone to serious periodic wear, namely rail corrugation. Combining the analysis results of wheel-rail contact stick-slip and wear features and wheel-rail system vibration characteristics, it may be concluded that the inner rail corrugation on the floating slab track with the small radius curves of metro is caused by the stick-slip vibrations induced by the unstable vibration modes of wheel-rail system corresponding to 664.1 Hz and 665.8 Hz, and the unstable modes are all presented as the bending vibrations of the inner wheel relative to the track. The sensitivity analysis of parameters indicates that properly increasing the vertical stiffnesses of the fastener and the steel spring may play a positive role in the control of corrugation.
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    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
    Abstract224)      PDF(pc) (3130KB)(231)       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. 
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    China Mechanical Engineering    2024, 35 (01): 0-.  
    Abstract164)      PDF(pc) (339KB)(231)       Save
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    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
    Abstract206)      PDF(pc) (9273KB)(230)       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.
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    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
    Abstract297)      PDF(pc) (4914KB)(225)       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%.
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    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
    Abstract145)      PDF(pc) (9640KB)(222)       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. 
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    Vibration and Lubrication Characteristics of Railway Vehicle Axle Box Bearings under Wheel-rail Excitation
    MA Qiaoying, YANG Shaopu, LIU Yongqiang,
    China Mechanical Engineering    2024, 35 (04): 580-590.   DOI: 10.3969/j.issn.1004-132X.2024.04.002
    Abstract180)      PDF(pc) (12680KB)(218)       Save
    An axle box bearings coupled with a railway vehicle model was developed based on Hertz contact and elastohydrodynamic lubrication theory. The effects of wheel-rail excitations on the vibration and oil film stiffness characteristics of axle box bearings were investigated. MATLAB/Simulink and UM were used to establish the bearing dynamic model and the railway vehicle model, respectively. The coupling relationship between the two was realized through the interaction force. The typical fault forms of bearings and wheelsets were simulated, and the impacts of these faults on bearing vibration and lubrication characteristics were analyzed in detail. The results show that lubrication may effectively reduce bearing vibrations. The partial bearing faults may increase the oil film stiffness, and bearing faults and wheel flats have a significant impact on lubrication. In addition, wheel-rail excitations reduce the vibration ratio of the bearing outer ring while increasing the vibration of other vehicle components and little effects on the vibrations of the car body.
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    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
    Abstract227)      PDF(pc) (6663KB)(217)       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.
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    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
    Abstract144)      PDF(pc) (1996KB)(214)       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.
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    Robust Control of High-pressure Pneumatic Pressure Servo Systems
    ZHANG Dijia1, 2, GAO Luping2, ZHOU Shaoliang2, GAO Longlong2, LI Baoren2
    China Mechanical Engineering    2024, 35 (07): 1141-1150.   DOI: 10.3969/j.issn.1004-132X.2024.07.001
    Abstract272)      PDF(pc) (7020KB)(210)       Save
    Parameter uncertainty and unmodeled dynamics of HPPS restricted the improvement of the control accuracy. An adaptive robust control method was proposed and applied to control the HPPS based on RISE. This paper considered the influencs of HESV control performance on the high-precision control of HPPS, and a cross-comparison test was designed. The results show that the HESV position control method may avoid sinusoidal signal distortions and reduce steady-state pressure jitter, and the HPPS pressure control method may improve the response speed and dynamic tracking capability of the systems.
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    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
    Abstract241)      PDF(pc) (2443KB)(205)       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.
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    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
    Abstract232)      PDF(pc) (7146KB)(205)       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. 
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    Study on Influencing Factors of Stress at Roots of Autonomous Sailboat Wing Sail Mast and Its Influencing Laws
    NIU Wenchao, SUN Zhaoyang, SHENG Zhongqi, YU Jiancheng, ZHAO Baode, ZHAO Wentao,
    China Mechanical Engineering    2023, 34 (22): 2647-2658.   DOI: 10.3969/j.issn.1004-132X.2023.22.001
    Abstract299)      PDF(pc) (15151KB)(201)       Save
    In order to study the influencing factors and influencing laws of the wing sail mast root stress, a numerical calculation model of the root stress of the wing sail masts was proposed based on the equivalence principle, and the accuracy of the proposed model was verified by finite element calculation. Based on the numerical calculation model of mast root stress, it was derived that there were 4 external parameters and 3 body parameters which affect the mast root stresses, the external parameters contain autonomous sailboat rolling period , rolling amplitude, rolling angle and deflection angle of wing sails. The body parameters contain mast center of gravity height, wing sail mass and the eccentric distance of wing sail. Based on the numerical calculation model, the influences of the above factors on the root stress of the masts were analyzed, and it is found that the stress values have a decreasing negative quadratic power function relationship with the rolling period , which is proportional to the rolling amplitude, the wing sail center of gravity height, the eccentric distance and wing sail mass, and the change curve of stress values with deflection angle coincides with the sinusoidal curve, and the stress value curve shows a sinusoidal waveform in one roll cycle. Finally, a method of adding stiffeners to optimize the structure was proposed for the stress concentration in the roots of the mast, and it was verified by the finite element calculation and the experimental analysis of turntable shaking. It is found that this method may reduce the stress value of the roots effectively during the working processes of the wing masts.
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    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
    Abstract350)      PDF(pc) (8857KB)(199)       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.
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    Lubrication Characteristics of Gear End Face Friction Pairs of Aviation High-speed Gear Pumps
    CHEN Yuan1, XIONG Dianfeng1, LI Yuntang1, GAO Yongcao2, LI Chuancang2, WANG Bingqing1, JIN Jie1
    China Mechanical Engineering    2024, 35 (07): 1178-1187.   DOI: 10.3969/j.issn.1004-132X.2024.07.005
    Abstract119)      PDF(pc) (9034KB)(198)       Save
    Aiming at the serious wear problems of gear end face friction pairs of aviation external gear pumps, a new compound texture combining Tesla valve groove type and elliptical shape was opened on the gear end faces to improve lubrication performance. Based on hydrodynamic lubrication theory and finite element simulation calculation method, a theoretical analysis model of gear textured end face friction pair lubrication was established. Pressure distribution and velocity distribution of fluid within the end face liquid films were simulated and analyzed under conditions with and without texture, and the effects of operating and structural parameters on the openness and sealing performance of gear end faces were studied. The results show that the hydrodynamic pressure generated by the texture may make the gear end face friction pairs run non-contact, which has a positive effect on reducing friction and increasing efficiency. With the comprehensive consideration of the openness and leakage control performance of gear end face friction pairs, groove depth is as 7~9 μm, height difference is as 5~6 μm, inclination angle is as 0°~10°, and shape factor is as 0.4~0.5 are the optimal structural parameters for the texture structure.
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    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
    Abstract234)      PDF(pc) (6709KB)(193)       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.
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    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
    Abstract161)      PDF(pc) (8767KB)(186)       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.
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    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
    Abstract251)      PDF(pc) (4853KB)(181)       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.
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    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
    Abstract179)      PDF(pc) (6922KB)(179)       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%. 
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    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
    Abstract324)      PDF(pc) (9506KB)(178)       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.
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    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
    Abstract230)      PDF(pc) (7710KB)(175)       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. 
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    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
    Abstract133)      PDF(pc) (4818KB)(167)       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.
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    Optimal Design of Slip Oil Pump Impeller Structures Based on NSGA-Ⅱ
    SUN Yongguo, JIN Xin, XUE Dong, SHAN Jianping, SHI Xiaochun
    China Mechanical Engineering    2024, 35 (03): 559-569.   DOI: 10.3969/j.issn.1004-132X.2024.03.018
    Abstract172)      PDF(pc) (6468KB)(166)       Save
    Slip oil pumps often needed to operate stably at high altitude and under low pressure conditions, which often led to cause problems such as insufficient oil supply and reduced efficiency. In order to get the best performance of the pump to meet the design requirements, this paper taken the impeller of a helicopter oil pump as the research object and to optimise the structure. The efficiency and lift of two typical working conditions at high altitude were selected as the optimisation targets, and the NSGA-Ⅱ was used to optimise the geometric parameters of the oil pump impellers, and the efficiency and lift of the oil pump before and after the optimisation were compared and analysed. CFD fluid simulation and experimental methods were used to verify the optimisation results. The results show that: the selected optimization parameters have a greater impact on the performance of the slip oil pumps, near the optimized slip oil pump vane positions the flow is more smooth, the high and low pressure areas of the excessively smooth, the energy loss is smaller, and the possibility of cavitation is reduced. The optimized slip oil pump design point lift increases 2.6 m, the efficiency increases 2.86%.
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    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
    Abstract180)      PDF(pc) (4400KB)(165)       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.
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    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
    Abstract357)      PDF(pc) (12172KB)(164)       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. 
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    A High-dimensional Uncertainty Propagation Method Based on Supervised Dimension Reduction and Adaptive Kriging Modeling
    SONG Zhouzhou1, 2, ZHANG Hanyu1, 2, LIU Zhao3, ZHU Ping1, 2
    China Mechanical Engineering    2024, 35 (05): 762-769,810.   DOI: 10.3969/j.issn.1004-132X.2024.05.001
    Abstract260)      PDF(pc) (3068KB)(163)       Save
     High-dimensional uncertainty propagation currently faced the curse of dimensionality, which made it difficult to utilize the limited sampling resources to obtain high-precision uncertainty analysis results. To address this problem, a high-dimensional uncertainty propagation method was proposed based on supervised dimension reduction and adaptive Kriging modeling. The high-dimensional inputs were projected into the low-dimensional space using the improved sufficient dimension reduction method, and the dimensionality of the low-dimensional space was determined by using the Ladle estimator. The projection matrix was embedded into the Kriging kernel function to reduce the number of hyperparameters to be estimated and improve the modeling accuracy and efficiency. Finally, the leave-one-out cross-validation error of the projection matrix was innovatively defined and the corresponding Kriging adaptive sampling strategy was proposed, which might effectively avoid large fluctuations of model accuracy in the adaptive sampling processes. The results of numerical and engineering examples show that, compared with the existing methods, the proposed method may obtain high-precision uncertainty propagation results with fewer sample points, which may provide references for the uncertainty analysis and design of complex structures. 
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    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
    Abstract244)      PDF(pc) (8141KB)(161)       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.
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    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
    Abstract246)      PDF(pc) (2724KB)(159)       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. 
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    Research Progresses and Prospects of Compression Molding of High-performance PBX
    SUN Haitao, ZHAN Mei, FAN Xiaoguang, GUO Jing, HAN Chao, ZHANG Jun
    China Mechanical Engineering    2024, 35 (01): 160-180.   DOI: 10.3969/j.issn.1004-132X.2024.01.016
    Abstract251)      PDF(pc) (15209KB)(159)       Save
    Pressed PBX was widely used in modern high-efficiency damage weapon warheads due to their excellent detonation and mechanics properties. The continuous changes in the future combat environment and strategic requirements were driving the development of pressed PBX towards high quality, high safety, and efficient molding and manufacturing. Thus, the current research status and problems facing the pressed PBX in molding quality and performance control, compression molding safety, and automatic manufacture were summarized herein. Firstly, the research progresses in the control of forming quality and performance of PBX was explored, including the evolution law and density inhomogeneity of explosive particle densification, damage evolution mechanism and interface performance control, residual stress detection and control. Furthermore, the compression molding safety of PBX and the current research status in digital and automatic manufacture were analyzed and discussed. Finally, based on the analysis of the current research progresses, the future development trends and challenges in the field of PBX compression molding were prospected.
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    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
    Abstract242)      PDF(pc) (9409KB)(158)       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.
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