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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 Abstract （1179）      PDF（pc） （50387KB）（895）       Knowledge map    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 | Comments（0）

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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 Abstract （1259）      PDF（pc） （5000KB）（828）       Knowledge map    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 | Comments（0）

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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 Abstract （654）      PDF（pc） （9652KB）（762）       Knowledge map    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 | Comments（0）

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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 Abstract （835）      PDF（pc） （9273KB）（554）       Knowledge map    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 | Comments（0）

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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 Abstract （651）      PDF（pc） （8185KB）（531）       Knowledge map    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 | Comments（0）

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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 Abstract （623）      PDF（pc） （2035KB）（513）       Knowledge map    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 | Comments（0）

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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 Abstract （1112）      PDF（pc） （4422KB）（508）       Knowledge map    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 | Comments（0）

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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 Abstract （983）      PDF（pc） （10399KB）（441）       Knowledge map    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 | Comments（0）

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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 Abstract （482）      PDF（pc） （1996KB）（383）       Knowledge map    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 | Comments（0）

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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 Abstract （750）      PDF（pc） （4853KB）（376）       Knowledge map    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 | Comments（0）

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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 Abstract （626）      PDF（pc） （6663KB）（356）       Knowledge map    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 | Comments（0）

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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 Abstract （413）      PDF（pc） （17686KB）（355）       Knowledge map    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 | Comments（0）

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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 Abstract （567）      PDF（pc） （8767KB）（350）       Knowledge map    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 | Comments（0）

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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 Abstract （639）      PDF（pc） （8141KB）（349）       Knowledge map    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 | Comments（0）

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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 Abstract （430）      PDF（pc） （4818KB）（349）       Knowledge map    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 | Comments（0）

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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 Abstract （676）      PDF（pc） （2443KB）（347）       Knowledge map    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 | Comments（0）

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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 Abstract （546）      PDF（pc） （9287KB）（340）       Knowledge map    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 | Comments（0）

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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 Abstract （447）      PDF（pc） （9640KB）（338）       Knowledge map    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 | Comments（0）

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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 Abstract （567）      PDF（pc） （6363KB）（335）       Knowledge map    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 | Comments（0）

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China Mechanical Engineering    2024, 35 (01): 0-.   Abstract （282）      PDF（pc） （339KB）（333）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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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 Abstract （621）      PDF（pc） （10849KB）（322）       Knowledge map    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 | Comments（0）

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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 Abstract （491）      PDF（pc） （6351KB）（317）       Knowledge map    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 | Comments（0）

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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 Abstract （584）      PDF（pc） （4400KB）（313）       Knowledge map    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 | Comments（0）

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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 Abstract （520）      PDF（pc） （12856KB）（288）       Knowledge map    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 | Comments（0）

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Comprehensive Thickness Control Technology of 1180 MPa Grade Ultra-high Strength Steels in Cold Tandem Rolling ZHANG Wenjun, WANG Wenqi, ZHANG Xiaodong, LIN Wei, ZHANG Yandong, BAI Zhenhua, China Mechanical Engineering    2024, 35 (02): 347-353，370.   DOI: 10.3969/j.issn.1004-132X.2024.02.019 Abstract （579）      PDF（pc） （5696KB）（279）       Knowledge map    Save To resolve the issues of thickness variation and thickness deviation at head and tail for ultra-high strength steels in continuous cold tandem rolling, a thickness deviation prediction model and a roll gap adjustment estimation model were established based on the metal mass flow equation firstly. In addition, a thickness control system was exploited, and optimal roll gap adjustment model was established. Finally, an optimization model for rolling speed and tension in the head and tail rolling processes of the strip steels was built. The first stand of continues cold tandem rolling unit was taken as the technical application objects to test the two typical ultra-high strength steels. The results demonstrate that the length of thickness deviation for the ultra-high strength steel AR4146E1 and DU6220A1 decreased from 70.3 m and 36.89 m to 16.85 m and 16.33 m respectively. Reference | Related Articles | Metrics | Comments（0）

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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 Abstract （547）      PDF（pc） （6468KB）（277）       Knowledge map    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%. Reference | Related Articles | Metrics | Comments（0）

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Intelligent Layout for Pipeline Supports of Nuclear Power Plant under Complex Load SUN Yuxiang, CHEN Li, LONG Bo, WANG Yanping, LIU Shihua, JIA Kun China Mechanical Engineering    2024, 35 (02): 317-323，336.   DOI: 10.3969/j.issn.1004-132X.2024.02.016 Abstract （526）      PDF（pc） （5695KB）（274）       Knowledge map    Save  Nowadays, the arrangement of pipeline supports for nuclear power plants is achieved by iterative manual calculations, which had many drawbacks such as high labour intensity, long design cycles, and high costs. An intelligent layout method for three-dimensional nuclear power pipeline supports was proposed based on particle swarm optimization-genetic algorithm hybrid algorithm and finite element mechanics analysis. The examples of intelligent arrangement of pipeline supports for typical nuclear pipelines show that the proposed method may automatically arrange multiple supports of different types in the global space of the pipeline to meet the Design and Construction Rules for Mechanical Equipment of Nuclear Island of Nuclear Power Plants, and greatly reduce workload. Reference | Related Articles | Metrics | Comments（0）

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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 Abstract （571）      PDF（pc） （9034KB）（272）       Knowledge map    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. Reference | Related Articles | Metrics | Comments（0）

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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 Abstract （546）      PDF（pc） （12680KB）（266）       Knowledge map    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. Reference | Related Articles | Metrics | Comments（0）

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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 Abstract （1760）      PDF（pc） （3068KB）（265）       Knowledge map    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.  Reference | Related Articles | Metrics | Comments（0）

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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 Abstract （729）      PDF（pc） （15209KB）（259）       Knowledge map    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. Reference | Related Articles | Metrics | Comments（0）

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A Multi Index Comprehensive Optimal Anti Impact Trajectory Planning Method RONG Yu, CHEN Gang, DOU Tianci, China Mechanical Engineering    2024, 35 (02): 305-316.   DOI: 10.3969/j.issn.1004-132X.2024.02.015 Abstract （529）      PDF（pc） （9989KB）（253）       Knowledge map    Save A comprehensive optimal trajectory planning method was proposed to improve the efficiency and impact resistance of robotic arms. Firstly, by establishing a 3-5-3 polynomial curve mathematical model, a joint motion trajectory with controllable endpoint motion parameters was constructed. Secondly, considering constraints such as joint position, velocity, and acceleration, the objective function was defined using the weighted coefficient method to achieve a comprehensive optimization of the action time, impact, and dexterity of the robotic arm. The dynamic weighting method was used in the design of the objective function to address the contradiction between joint velocity and impact. Finally, for the standard particle swarm optimization algorithm, the Latin hypercube sampling function was used to homogenize the population, and a random inertia weight update strategy was proposed to obtain an improved particle swarm algorithm. This algorithm was used to optimize the objective function and obtain the comprehensive optimal motion trajectory. Simulation and prototype experiments were conducted, and the experimental results demonstrate the feasibility of the proposed method. Reference | Related Articles | Metrics | Comments（0）

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Assembly Array Tractile State Sensing Technology of Micro Flexible Flat Cables LIN Jie, HU Zhikai, LIU Siyuan, TANG Weiwei, CHU Zhongyi China Mechanical Engineering    2024, 35 (02): 287-292，304.   DOI: 10.3969/j.issn.1004-132X.2024.02.013 Abstract （454）      PDF（pc） （7211KB）（252）       Knowledge map    Save For the problems of small device size and visual occlusion during the micro flexible flat cable assembly operations, an assembly state sensing technology of micro flexible flat cables was proposed based on capacitive array tactile sensors herein. Firstly, the mechanism of capacitive three-dimensional tactile sensing was analyzed, and a highly sensitive array tactile sensor based on vertical topological mesh dielectric layer was designed to realize highly sensitive sensing of the assembly state of the micro flexible flat cables. Secondly, in order to overcome the limitation of wiring complexity and array scanning cycle, based on the expansion of capacitive digital chip, the highly dynamic three-dimensional array information scanning system was designed and the highly dynamic sensing for assembly states of micro flexible flat cables was realized, and the miniaturized capacitive array tactile sensors were fabricated integrally. Finally, the robot micro flexible flat cable assembly operating system was built and the array tactile information features were collected and analyzed in real time during the assembly processes, so as to verify the accuracy and effectiveness of the proposed technology. Reference | Related Articles | Metrics | Comments（0）

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Research on Optimal Pose Set Planning Method under Physical Constraint Robot Kinematics Calibration JIANG Jiguang, HOU Jue, SU Chengzhi, BA Qijiao, TIAN Aixin, XU Mingyu China Mechanical Engineering    2024, 35 (03): 472-480.   DOI: 10.3969/j.issn.1004-132X.2024.03.009 Abstract （539）      PDF（pc） （5499KB）（252）       Knowledge map    Save In the processes of kinematics calibration of industrial robots under physical constraints, the calibration accuracy was affected by the selection of the pose set, which in turn was constrained by the calibration devices. To solve these problems, an optimal pose set planning method was proposed based on sampling interval evaluation combined with pose set optimization. Firstly, the robot kinematics model and the distance constraint calibration model were established, and the robot system parameter error constraint equation and error Jacobian matrix were calculated. Secondly, the workspace of robot was divided into spatial grids and evaluate each grid interval using Latin hypercube sampling combined with observable indicators to obtain the optimal sampling interval. Finally, based on offline data, the calibration accuracy prediction model was established based on offline data and search for the optimal pose set within the optimal sampling interval. By planning and verifying the optimal pose set for the ZhongRui RT-608 robot, the results show that the average fitting sphere radius after calibration is 0.3947 mm based on the optimal pose set, which is 57.98% lower than that of the random pose set. Reference | Related Articles | Metrics | Comments（0）

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Design of Twisting Climbing Wheeled Inspection Robot for Mining Wire Ropes TANG Chaoquan, TONG Binghang, TANG Wei, ZHANG Gang, WANG Siyuan, TANG Hongwei, LIU Bei, ZHOU Gongbo China Mechanical Engineering    2024, 35 (10): 1732-1739.   DOI: 10.3969/j.issn.1004-132X.2024.10.003 Abstract （623）      PDF（pc） （6279KB）（242）       Knowledge map    Save In response to the unmanned inspection requirements of mining wire ropes, a rope-twisting climbing inspection robot was designed and developed. Compared to traditional axial climbing robots, which required approximately 91.5% of the driving force. When carrying a load of 3 kg, the robot may overcome obstacles with a height 0.6 mm higher than that of axial climbing robots. With an obstacle height of 3 mm, the maximum load capacity exceeds that of axial climbing robots by 0.4 kg. Climbing experiments were conducted under simulated deep mine conditions with wire rope vibrations. The results show that the climbing robots exhibite stable climbing performance when the wire ropes are stationary, achieving a maximum climbing speed of 8.25 m/min and capable of continuous climbing for 500 m. Under low-frequency large-amplitude vibration conditions, the climbing speed of the robot is higher than that when stationary, while under high-frequency small-amplitude vibration conditions, slight fluctuations in climbing speed are observed due to wire rope vibrations. Reference | Related Articles | Metrics | Comments（0）

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Research on Microfluidic Chip Fluid Dynamic Pressure Polishing Process FU Zhenfeng, WANG Zhenzhong, WANG Biao China Mechanical Engineering    2024, 35 (03): 534-540.   DOI: 10.3969/j.issn.1004-132X.2024.03.015 Abstract （464）      PDF（pc） （6895KB）（240）       Knowledge map    Save Microstructure polishing ball was designed based on fluid dynamic pressure lubrication theory, through theoretical analysis of the microstructure in the polishing ball rotation processes to generate more fluid dynamic pressure. Fluent was used to analyze the type of microstructure and the effects of microstructure size on the dynamic pressure generated by polishing, the generated polishing force was obtained by fitting Fluents data via MATLAB. After obtaining the better parameters of microstructure, area polishing of the microfluidic chips was performed. The surface roughness of the microfluidic chip plane area is reduced from 1.330 nm to 0.658 nm, and the surface roughness of the microfluidic chip flow channel is reduced from 0.737 nm to 0.379 nm. Thus, the applications of hydrodynamic pressure polishing process to the deterministic polishing of microfluidic chips may be further explored. Reference | Related Articles | Metrics | Comments（0）

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China Mechanical Engineering    2025, 36 (04): 1-.   Abstract （328）      PDF（pc） （293186KB）（240）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Review for Research of Fatigue Life Prediction of Welded Structures under Complex Loads and Extreme Environments DONG Zhibo1, WANG Chengcheng1, LI Chengkun1, LI Junchen2, ZHAO Yaobang2, LI Wukai2, XU Aijie2 China Mechanical Engineering    2024, 35 (05): 829-839.   DOI: 10.3969/j.issn.1004-132X.2024.05.008 Abstract （806）      PDF（pc） （6000KB）（237）       Knowledge map    Save The welded joints were susceptible to defects and stress concentration, rendering them vulnerable areas for fatigue crack initiation and propagation under fatigue loads. In comparison to homogeneous materials, the microstructure and stress localization in each of regions for the joints further complicated the fatigue issue in welded structures. Unlike ideal experimental conditions, the actual service environments of welded structures were intricate, it was necessity to consider the coupling characteristics between environmental factors and welded structures when predicting welded structure fatigue life. Therefore, the internal factors influencing welded structures were summarized and analyzed while reviewing existing life prediction models from perspectives encompassing complex loads and extreme service environment. Combining the latest research progresses, the recommendations were proposed to enhance fatigue life assessment methods for the welded structures. Reference | Related Articles | Metrics | Comments（0）

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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 Abstract （623）      PDF（pc） （7020KB）（236）       Knowledge map    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. Reference | Related Articles | Metrics | Comments（0）

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Research on Self-repairing Structure Design and Repair Performance Based on Additive Manufacturing Technology ZHANG Zhen, GUO Ce, HU Caiji, ZHENG Wei China Mechanical Engineering    2024, 35 (01): 144-151.   DOI: 10.3969/j.issn.1004-132X.2024.01.014 Abstract （747）      PDF（pc） （10846KB）（235）       Knowledge map    Save Taking lightweight sandwich plate structures as the main research object, the self-repairing design and implementation method were studied according to the fracture failure forms of the structures. The structural samples were prepared by additive manufacturing technology, and the restoration effect of the repaired structural mechanics properties was compared and analyzed through experimental tests. The results show that the designed sandwich plate self-repairing structure has a good ability to repair cracks, and the stress resistance of the repaired structure is restoreds to 85.6% of the original structures. Reference | Related Articles | Metrics | Comments（0）