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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 （2042）      PDF（pc） （3068KB）（775）       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 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 （1388）      PDF（pc） （4422KB）（767）       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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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 （811）      PDF（pc） （17686KB）（553）       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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Depth of Cut Control for Thin-walled Parts in Robotic Milling Based on FLADRC SHI Long, ZHOU Hexiang, LI Zhoulong China Mechanical Engineering    2025, 36 (04): 671-680.   DOI: 10.3969/j.issn.1004-132X.2025.04.003 Abstract （2534）      PDF（pc） （8675KB）（553）       Knowledge map    Save Weakly rigid large thin-walled parts had large deformations and vibrations during robotic thinning machining, which led to a degradation of the surface quality of the workpieces and difficulties in ensuring the accuracy of the remaining wall thickness. To this end, a VCM-driven follower support head was used for vibration and deformation suppression, and a FLADRC based control strategy was proposed for depth of cut of robotic milling thin-walled parts. In order to verify the effectiveness of the control strategy, the system control models were firstly established based on the MATLAB/Simulink simulation and experimental platform, and the simulation analysis was carried out, then experimental verification was carried out on the thin-walled parts robotic milling experiment platform. Both of the simulation and experimental results show that the depth-of-cut control strategy based on the follower support head may significantly suppress the vibrations and deformations during the machining processes of thin-walled parts and effectively ensure the accuracy of the remaining wall thickness. In addition, compared with the traditional fuzzy PID control, the FLADRC has a better control effectiveness and exhibits higher robustness in the presence of external disturbances. Reference | Related Articles | Metrics | Comments（0）

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Nanosecond Laser Machining of Spiral Grooves of Dry Gas Seal Rotational Ring Surfaces Wenqian LI, Zhanqiang LIU, Jinfu ZHAO, Bing WANG, Yukui CAI China Mechanical Engineering    2025, 36 (10): 2207-2214.   DOI: 10.3969/j.issn.1004-132X.2025.10.006 Abstract （545）   HTML （78）    PDF（pc） （3972KB）（553）       Knowledge map    Save An experimental study on the nanosecond laser processing of the spiral groove on the dry gas seal rotational ring surfaces made of GH4169 was carried out. Orthogonal tests and one-factor methods were utilized to reveal the effects of laser power， scanning speed， filling spacing and repetition frequency on the spiral groove depth and bottom roughness Ra， and to determine the appropriate combination of laser processing parameters. The results show that the greatest influence on the depth of the spiral grooves on the surfaces of GH4169 alloy is the laser power， followed by the repetition frequency and the scanning speed， and the greatest influence on the roughness of the groove bottoms is the scanning speed， followed by the repetition frequency and the scanning spacing. With the laser power of 18 W， scanning speed of 40 mm/s， fill spacing of 0.005 mm， and repetition frequency of 50 kHz， the spiral grooves on the machined rotational ring surfaces is able to meet the machining requirements of groove depth of 7 μm， and groove bottom roughness of Ra≤0.8 μm. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Chatter Identification Method for Heavy-duty Robotic Milling Systems Based on Variational Mode Filtering and Attention Mechanism LIANG Zhiqiang1, 2, CHEN Sichen1, DU Yuchao1, LIU Baolong1, 2, GAO Zirui1, YUE Yi3, XIAO Yubin4, ZHENG Haoran1, QIU Tianyang1, LIU Zhibing1 China Mechanical Engineering    2025, 36 (05): 1018-1027,1073.   DOI: 10.3969/j.issn.1004-132X.2025.05.013 Abstract （1554）      PDF（pc） （7393KB）（546）       Knowledge map    Save A method was proposed for identifying chatters in heavy-duty robotic milling systems by integrating variational mode filtering with fixed parameters, envelope filtering and an attention mechanism network identification. Initially, variational mode filtering theory was applied to eliminate non-chatter signal components in the high-frequency ranges by optimally selecting a quadratic penalty. Then, to swiftly identify the current machining conditions, the envelope filtering method was employed, leveraging signal time domain distribution and the frequency domain mapping law to remove the spindle speed-related signal components in the low-frequency ranges. Subsequently, a network identification model incorporating an attention mechanism was developed to identify preprocessed multi-temporal short-term signal segments for machining condition identification, followed by verification experiments on heavy-duty robotic milling systems. Experimental analysis results demonstrate that by eliminating non-chatter signals in the high-frequency ranges and spindle speed-related components in the low-frequency ranges, the accuracy of regenerative chatter identification is significantly enhanced, achieving an identification accuracy of 98.75%. Compared with alternative identification methods, the proposed method may effectively identify regenerative chatters during heavy-duty robotic milling processes, thus offering valuable technical support for future online chatter suppression of heavy-duty robotic milling. 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 （808）      PDF（pc） （9034KB）（538）       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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Molecular Dynamics Simulation of Microscopic Crack Initiation and Extension Mechanism in 8Cr4Mo4V Bearing Steels Tianyu MA, Gu GONG, Hongrui CAO, Jianghai SHI, Xunkai WEI, Lijun ZHANG China Mechanical Engineering    2025, 36 (10): 2179-2189.   DOI: 10.3969/j.issn.1004-132X.2025.10.003 Abstract （601）   HTML （59）    PDF（pc） （7456KB）（473）       Knowledge map    Save To investigate the influences of cementite on the mechanics properties of the matrix and the initiation and propagation of microcracks in 8Cr4Mo4V bearing steels， molecular dynamics models were used to systematically analyze the effects of cementite's geometric parameters （such as shape， size， and position） on crack initiation and extension mechanism. And combined with cohesive force theory， the characteristics of interface crack propagation were studied. The results indicate that cementite significantly enhances the mechanics properties of the bcc-Fe matrix， with smaller cementite particles providing a more pronounced strengthening effectiveness. While the shape and position of cementite exert a relatively minor impact on overall mechanics performance， sharper inclusions accelerate crack propagation， and the position of inclusions determines the crack propagation path. Furthermore， interfaces between the bcc-Fe matrix and cementite， as well as twin boundaries with larger misorientation angles， exhibit increased resistance to crack initiation and propagation. Table and Figures | 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 （808）      PDF（pc） （6279KB）（467）       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 Progresses for Machining Characteristics and Field-assisted Techniques of γ-TiAl Alloys FAN Tao1, 2, YAO Changfeng1, 2, TAN Liang1, 2, SHAN Chenwei１, ２, XIA Ziwen1, 2 China Mechanical Engineering    2025, 36 (04): 636-645.   DOI: 10.3969/j.issn.1004-132X.2025.04.001 Abstract （2167）      PDF（pc） （25364KB）（458）       Knowledge map    Save γ-TiAl alloys, due to their low density, high specific strength and excellent high-temperature oxidation resistance had broad application potentials in the aerospace fields. However, due to their high brittleness and low room-temperature plasticity, they were considered typical difficult-to-machine materials, with challenges such as high cutting forces, rapid tool wear and surface defects during the machining processes. In recent years, field-assisted machining technologies provided new solutions to these issues. The material properties, machining characteristics, and surface integrity of γ-TiAl alloys were systematically analyzed, with a focus on the research progresses of field-assisted machining technologies, including their applications in reducing cutting forces, extending tool life and improving surface quality. Additionally, the current research limitations and future development trends were sorted out, aiming to provide theoretical and technical references for the efficient machining of γ-TiAl alloys.  Reference | Related Articles | Metrics | Comments（0）

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Effects of Forced Positioning&Clamping on Geometric and Physical Assembly Performances for Composite Structures and Collaborative Guarantee Strategies GUO Feiyan1, ZHANG Yongliang2, LIU Jialiang1, ZHANG Hui2 China Mechanical Engineering    2025, 36 (04): 655-670.   DOI: 10.3969/j.issn.1004-132X.2025.04.002 Abstract （1974）      PDF（pc） （7015KB）（458）       Knowledge map    Save The large-size & thin-walled aviation composite structures had low forming accuracy and huge in-plane warping deformation. The accumulation of assembly errors, unexpected geometric gaps and shape deviations were prone to occur at the joining areas. In engineering, passive reduction actions, such as applying local clamping forces was usually applied, but uneven internal stress distribution and even internal damages would be occurred, which affected the mechanical performances of the structures in service directly. Firstly, the principle of forced positioning clamping was explained, and the affection on geometric accuracy and mechanical properties of weak rigid composite parts was analyzed. Secondly, starting from the analysis of two main aspects, i.e. optimization on forced clamping process parameters before assembly, and flexible positioning force&position adjustment of fixtures during assembly, five key technologies were solved with detailed technical solutions, i.e. setting forced assembly force limits, reduction of geometric gaps, prediction of stress/damage evolution, reverse optimization of forced clamping process parameters, and precise measurement of assembly stress&damage. Then the active control of shape&force coupling and macro & micro collaborative guarantee in the clamping processes for assembly performance, could be achieved. Finally, for the composite assembly structures, from the perspective of practical engineering applications, the future working focus towards high assembly quality and efficient, and low-cost assembly goals were proposed. Reference | Related Articles | Metrics | Comments（0）

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Rolling Bearing Fault Diagnosis of Wind Turbines Based on Frequency Domain Group Sparse Model with Graph Regularization Constraints LI Jimeng, WANG Ze, SHI Qingxin, MENG Zong China Mechanical Engineering    2024, 35 (11): 1909-1919.   DOI: 10.3969/j.issn.1004-132X.2024.11.002 Abstract （1739）      PDF（pc） （11269KB）（441）       Knowledge map    Save Due to effects of the non-stationary operations, noisy working environment and strong electromagnetic interference for the wind turbines, the fault impulses of rolling bearings were submerged by strong noise, and the weak features were difficult to accurately identify. To solve the above problems, a frequency domain group sparse model with graph regularization constraints was proposed, which might effectively extract fault features of rolling bearings without periodic prior knowledge. Firstly, vibration signals were converted into graph signals to construct the graph regularization constraints, and the structured information was utilized to guide the penalty strength to improve the accuracy of sparse reconstruction. Secondly, the frequency domain group sparse model with graph regularization constraints was constructed, the method was given to determine the shrinkage threshold of the in-group components, and the objective function was simplified with the proximal mapping to optimize the solution. Finally, the parameters of the model were optimized by using the constructed comprehensive index and the moth flame optimization algorithm, and rolling bearing faults were identified by the envelope spectrum analysis of the reconstructed signals in the time domain. Numerical simulation and experimental results demonstrate that the proposed method has good anti-noise performance and may effectively extract weak fault features of rolling bearings under strong noise interference. Reference | Related Articles | Metrics | Comments（0）

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A Sequential Simulation Method for Dynamic Uncertainty Analysis of Rigid-flexible Coupling Systems under Interval Process Excitations LIU Yanhao, NI Bingyu, TIAN Wanyi, JIANG Chao China Mechanical Engineering    2024, 35 (05): 770-783.   DOI: 10.3969/j.issn.1004-132X.2024.05.002 Abstract （1641）      PDF（pc） （9281KB）（432）       Knowledge map    Save For the dynamic problem of rigid-flexible coupling systems under dynamic uncertain excitations, an interval process model-based sequential simulation method was proposed for uncertainty analysis, which aimed to obtain the upper and lower bounds of the system dynamic responses such as structural vibrations and mechanism kinematics, by sequential sampling of the interval process and the rigid-flexible coupling dynamics simulations. The construction and numerical solution of the dynamic equation of the rigid-flexible coupling systems with central rigid body and flexible beam were introduced. Aiming at the dynamic analysis of rigid-flexible coupling systems under uncertain dynamic excitations, the interval process model and the interval K-L expansion were introduced to quantify and represent the dynamic uncertainty efficiently, and a sequential simulation method was proposed to solve the upper and lower bounds of the dynamic responses of the system mechanism motions and structural vibrations. The method used a sequential simulation strategy to identify the interval process parameter sample sets that contributed to the upper or lower bounds of dynamic responses in the cur rent simulation sequence, and served as the local encrypted sampling center in the next simulation sequence, which might effectively avoid the inefficient convergence problem caused by excessive invalid sampling simulations when calculating the upper and lower bounds of dynamic response in direct Monte Carlo simulation. Finally, three examples were given to verify the effectiveness of the proposed method. The results show that the sequential simulation method has better computational efficiency and accuracy than that of the direct Monte Carlo simulation method for solving the upper and lower bounds of the rigid-flexible coupling systems large overall motions and vibration responses. 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 （795）      PDF（pc） （7020KB）（410）       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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Tribological Properties of Polyelectrolyte-Modified PEEK Composite Materials GAO Chuanbao, ZHANG Xinyue, CEN Jiajia, CHEN Qin, FENG Haiyan, CHEN Kai, ZHANG Dekun China Mechanical Engineering    2026, 37 (1): 14-21.   DOI: 10.3969/j.issn.1004-132X.2026.01.002 Abstract （306）   HTML （53）    PDF（pc） （2572KB）（401）       Knowledge map    Save To enhance the tribological properties of PEEK， a “modify-then-form” approach was proposed. Hydrophilic SPMK was grafted onto the PEEK powder surface via UV-induced polymerization， then the PEEK-SPMK composites were prepared by hot-pressing. The friction and wear behaviors of modified PEEK under various operating conditions were analyzed， revealing the influence mechanism and lubrication mechanism of polyelectrolyte SPMK powder modification on the tribological behavior of PEEK composites.Results indicate that SPMK powder modification significantly enhances PEEK surface wettability. The friction coefficient（0.028） and wear rate（5.6×10{}^{-\mathrm{7}} mm³/（N·m）） of PEEK-SPMK in physiological saline are markedly reduced compared to pure PEEK. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Bearing Fault Diagnosis of Mining Drilling Rig with Time-frequency-fused Deep Network ZOU Xiaoyu1, 3, SUN Guoqing1, WANG Zhongbin1, 3, PAN Jie2, LIU Xinhua1, 3, LI Xin1, 3 China Mechanical Engineering    2024, 35 (08): 1405-1413，1448.   DOI: 10.3969/j.issn.1004-132X.2024.08.009 Abstract （2038）      PDF（pc） （9001KB）（387）       Knowledge map    Save To solve the problems of weak and noisy bearing fault features caused by the low-speed and heavy-load operating characteristics of mining drilling rigs, a fault diagnosis method was proposed for mining rig bearings, named time-frequency-fused deep network. It considered the limitations of fault diagnosis with single modality, and then jointly characterizes two modal features of the time domain and time-frequency domain. The designed diagnostic network differentially embeded specific attention mechanism in different modules to extract multi-dimensional key fault features. Finally, the proposed method was validated on the experimental equipment and the Case Western Reserve University bearing dataset. The results show that the proposed method may automatically extract sufficient fault features combining two domains. It has higher accuracy and noise immunity than those with a single domain. Reference | Related Articles | Metrics | Comments（0）

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Design of Jig and Fixture for Machining Precision Forged Blade Tenons of Aeroengine ZHANG Shen1, LIANG Jiawei2, WU Dongbo3, WANG Hui4, ZHAO Bing1, XU Lijun5, ZHOU Fen5 China Mechanical Engineering    2025, 36 (04): 703-714.   DOI: 10.3969/j.issn.1004-132X.2025.04.007 Abstract （1734）      PDF（pc） （9510KB）（380）       Knowledge map    Save Precision forged blades of aeroengine were a typical thin-walled parts with complex curved surface. When milling the blade tenons, it was difficult to locate and easy to produce deformations and vibrations. Aiming at the above problems, a design method of multi-point clamping fixture for precision forged blades was proposed, and a low stress hard clamping fixture was designed. Static analysis was used to optimize the clamping position, select the coping element materials and optimize the clamping method. The effectiveness of the fixture was tested by modal tests and vibration tests. The results show that the low-band amplitude of the system is reduced by 50%, the high-band amplitude by 75%, the first-order resonance frequency is increased from 210 Hz to 402 Hz, the damping ratio under the peak value is increased from 17.4% to 25.9%, the effective value of vibration displacement signals is reduced by 35%, and the machining error margin is reduced by 59%. Reference | Related Articles | Metrics | Comments（0）

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China Mechanical Engineering    2025, 36 (04): 1-.   Abstract （431）      PDF（pc） （293186KB）（378）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Study on Lubricating Performances and Mechanism of Nano-carbon Balls Cutting Fluids SUN Hao1, LAN Qixin2, YAO Bin2, LU Jingjing1, ZHANG Jinhui2, PAN Zhirong2, ZHAO Kexin2 China Mechanical Engineering    2025, 36 (04): 715-723.   DOI: 10.3969/j.issn.1004-132X.2025.04.008 Abstract （1917）      PDF（pc） （8056KB）（373）       Knowledge map    Save Nano-carbon balls cutting fluid was applied to the cutting processes of difficult-to-machine aerospace gear steels(15Cr14Co12Mo5Ni2W), and the lubrication enhancement effects of nano-carbon particles on the cutting fluid were investigated. Firstly, a cutting force model for metal cutting was established to analyze the relationship between cutting lubrication and cutting forces. Furthermore, through combined friction-wear tests and milling experiments, the lubrication performance of nano-carbon balls cutting fluid was evaluated in terms of friction coefficient, wear volume, friction surface quality, and cutting forces. Compared with the base cutting fluid, when the mass fraction of nano-carbon is reached 0.02%, the milling forces for the gear steels are decreased by over 10%, and surface roughness is reduced by more than 15%. Experimental observations reveal that nano-carbon particles on the friction contact surfaces preferentially are adsorbed onto micro-peak regions with higher surface free energy, forming a nano-carbon adsorption film. Lubrication mechanism analysis indicates that this adsorption film may exert a friction-reducing “micro-bearing” effects. Reference | Related Articles | Metrics | Comments（0）

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Fault Diagnosis of Rotating Machinery Bearings Based on Multi-source Wavelet Transform Neural Network GUO Haiyu1, ZOU Shenggong1, ZHANG Xiaoguang2, 3, 4, LU Fanfan2CHEN Yang2, WANG Han2, XU Xinzhi2 China Mechanical Engineering    2024, 35 (11): 2026-2034.   DOI: 10.3969/j.issn.1004-132X.2024.11.014 Abstract （2011）      PDF（pc） （5837KB）（369）       Knowledge map    Save  A multi-source wavelet time-frequency transform convolutional neural network was proposed to address the issues of limited fault samples in rotating machinery bearing fault diagnosis, along with the vulnerability to overfitting and the poor generalization ability of traditional models when dealing with small datasets. Initially, for high-frequency data obtained from a single vibration sensor, a wavelet transform-based time-frequency convolutional layer was formulated to integrate both the real and imaginary components of wavelet coefficients. Here, the real component represented the amplitude information of vibration signals, while the imaginary component depicted phase information. Compared with a convolution layer that only considering real part, this convolutional layer may extract comprehensive time-frequency features. Subsequently, the time-frequency convolutional layer was employed to independently extract features from high-frequency data acquired by multi-sensors on a single device, and these features were then concatenated. Lastly, a dense module utilizing lightweight depth-separable convolution was developed to conduct further feature extraction from the concatenated features, facilitating fault classification. The effectiveness of the model was confirmed through experimentation using Case Western Reserve University rolling bearing dataset, achieving an accuracy of 98.5%.Additionally, the model was deployed for fault diagnosis in rotary kilns, belt conveyors, and grate coolers, demonstrating an average accuracy of 97.19%. Reference | Related Articles | Metrics | Comments（0）

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Bearing Fault Data Generation Method Based on WLT-ACGAN JIAO Huachao, SUN Wenlei, WANG Hongwei China Mechanical Engineering    2025, 36 (03): 546-557.   DOI: 10.3969/j.issn.1004-132X.2025.03.018 Abstract （2104）      PDF（pc） （7836KB）（351）       Knowledge map    Save Using data generation method to generate high-quality data which made time-domain and frequency-domain features consistent with the real signals of bearing faults, and constructing balanced dataset, were of great significance for the establishment of an efficient diagnostic model of bearing faults in the case of data imbalance. In order to address the limitations of the existing data generation methods, which focused on a single feature in time or frequency domains, WLT-ACGAN was proposed herein. Firstly, a WLT network was constructed with a multi-layer neural network based on the principle of wavelet transform. The wavelet transform and inverse transform were simulated, and the mapping relationship between time-domain signal and frequency-domain signal was established. Secondly, the WLT network was embedded into ACGAN model as the primary component of model generator. Finally, two discriminators were constructed with different functions, enabling the improved ACGAN to learn time-domain and frequency-domain feature information of authentic bearing vibration signals concurrently. Experimental results show that the bearing vibration signals generated by WLT-ACGAN model exhibit consistent time-domain and frequency-domain features with those of the actual bearing vibration signals. Furthermore, the fault diagnostic model constructed with the balanced dataset augmented by the generated signals exhibits a high degree of accuracy when the data are imbalanced. Reference | Related Articles | Metrics | Comments（0）

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Heat Exchange Micro-tube Vibration Analysis and Reliability Evaluation Methods for Diaphragm Micro-channel Pre-coolers WANG Zheng, MA Tongling, WANG Bowen, GU Meidan China Mechanical Engineering    2024, 35 (05): 869-876,885.   DOI: 10.3969/j.issn.1004-132X.2024.05.012 Abstract （1585）      PDF（pc） （3506KB）（344）       Knowledge map    Save For the problem of heat exchange micro-tube vibration reliability of diaphragm micro-channel pre-coolers which was one of the key components of pre-cooled air breathing combined cycle engines, the method and mathmatical model for calculating the natural vibration characteristics of heat exchange micro-tubes were developed, and the vibration modes and their mechanism of heat exchange micro-tube with the action of high speed air flow were studied. Then, the vibration modes including the vortex shedding excitation vibration, the turbulent buffeting vibration and the elastic excitation vibration were taken into account, and the reliability evalutating model of pre-coolers with heat exchange micro-tube vibration failure mode was derived. The pre-cooler heat exchange micro-tube vibration reliability of change rules were revealed. The results show that the natural vibration frequency of heat exchange micro-tube is affected by the parameters including outside diameter, pipe wall thickness, adjacent support plate spacing, material properties and so on, and the vibration modes of heat exchange micro-tube have the characteristics of sine function. Three important vibration modes including the vortex shedding excitation vibration, the turbulent buffeting vibration and the elastic excitation vibration those may happen in the heat exchange micro tubes of pre-cooler with the action of high speed air flow. And with the increasing of flow velocity of cooled working fluid, the heat exchange micro-tube vibration reliability of pre-coolers decreases firstly, and then increases and approaches a certain value. In order to avoid the resonance of heat exchange micro tubes, the structural parameters may be designed rationally with the operating profile and the flow and heat transfer characteristics may be also taken into account. Reference | Related Articles | Metrics | Comments（0）

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Aerodynamic Optimization of Radial Turbines Based on Surrogate Model of Pre-screened Strategies and DFFD Parameterization Tianqi WANG, Jiang CHEN, Hang XIANG, Xiaofei SONG China Mechanical Engineering    2025, 36 (10): 2171-2178.   DOI: 10.3969/j.issn.1004-132X.2025.10.002 Abstract （430）   HTML （35）    PDF（pc） （3107KB）（338）       Knowledge map    Save There were some problems such as difficult geometric control， many control variables and low optimization efficiency in aerodynamic optimization of three-dimensional complex blade surfaces of radial turbines. To solve these problems， multi-degree-of-freedom parameterization of radial turbine runner and blade multidimensional geometry were implemented based on DFFD method. Then an differential evolution algorithm assisted by surrogate models of pre-screened strategies（Pre-SADE） was introduced. Finally， a data-driven three-dimensional aerodynamic optimization platform for centripetal turbines was constructed by combining python and batch script of process automation. The platform was used to carry out the joint optimization design of flow channel-static/rotating blades for the radial turbines. The results show that after optimization， the adiabatic efficiency and mass-flow of the design point of the centripetal turbines are increased by 1.66% and 1.7% respectively， which effectively reduces the shock intensity in the guide vane channel and the shock loss on the suction surfaces of the guide vane， and the efficiency characteristics of the design rotational speed are improved in all working conditions. Finally， the method and platform may ensure the aerodynamic optimization efficiency， and effectively reduce the optimization variables and sample real evaluation times， significantly improve the optimization efficiency， and meet the rapid and elaborate optimization design requirements of radial turbines. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Tribological Properties and Mechanism of Nanostructured Carbon Films under Coupling Effect of Temperature and Electric Field YU Zhimin, CHEN Lei, FAN Xue China Mechanical Engineering    2026, 37 (1): 30-39.   DOI: 10.3969/j.issn.1004-132X.2026.01.004 Abstract （214）   HTML （27）    PDF（pc） （7563KB）（334）       Knowledge map    Save The nanostructured carbon films including amorphous carbon films and graphene nanocrystalline carbon films were prepared on SiO2 substrates. A self-designed reciprocating tribometer capable for applying coupled multi-physical fields was employed to investigate the tribological properties of the different nanostructured carbon films under the coupling effect of temperature and electric field. At room temperature， the electric field was the dominant factor for affecting the friction coefficient of nanostructured carbon films. When the temperature of tribopair was 200 ℃， temperature became the main influencing factor. Under the coupling effects of temperature and electric field， the structured evolution to graphitic-like structure leads the reduction of friction coefficient of amorphous carbon film. While the nanostructure of graphene nanocrystalline carbon film is stable， but the aggravated wear results in significant fluctuations of friction coefficient. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Cross-domain Fault Diagnosis of Bearings Based on Joint Subdomain Contrast Alignment YANG Kang1, CHEN Xuejun1, 2, ZHANG Lei3, LIU Feng3 China Mechanical Engineering    2025, 36 (05): 1065-1073.   DOI: 10.3969/j.issn.1004-132X.2025.05.018 Abstract （2353）      PDF（pc） （5744KB）（326）       Knowledge map    Save The fault data of bearings exhibited significant distribution discrepancies under varying operating conditions， relatively low diagnostic accuracy was resulted in practical fault detection models. Additionally， most existing research on cross-domain bearing fault diagnosis primarily emphasized inter-domain alignment and intra-class comparison， while neglecting the influences of interactions between subdomains. Therefore， a cross-domain fault diagnosis method of bearings was proposed based on joint subdomain contrast alignment. In order to highlight the fault features， the bearing vibration signals were transformed into time-frequency graph by short-time Fourier transform， and the fault features were obtained by inputting them into the feature extraction module. Domain adaptation methods achieved cross-domain recognition by transferring knowledge learned from the source domain to the target domain. During the domain adaptation processes， a joint subdomain contrast alignment strategy was used to bring samples from the same subdomain closer together while separating samples from different subdomains， which aligned the subdomain distributions of the same class samples among the source and target domains， thereby enhancing the models generalization ability in the target domain. Resnet34 was used as the feature extraction network on the model architecture， and the maximum mean difference was used at the output of the network to align the global distribution of the source domain and the target domain. Compared with the classical domain adaptation methods， the experimental results on the bearing fault data set of Case Western Reserve University shows that the cross-domain fault diagnosis method of bearings based on joint subdomain contrast alignment has better feature transfer ability.  Reference | Related Articles | Metrics | Comments（0）

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Method for Accelerated Tribological Property Evolution Experiments of Conformal Contact Surfaces in Mixed Lubrication Regime ZHANG Ziyang, GONG Yajing, WANG Yuechang China Mechanical Engineering    2026, 37 (1): 22-29.   DOI: 10.3969/j.issn.1004-132X.2026.01.003 Abstract （205）   HTML （28）    PDF（pc） （2108KB）（325）       Knowledge map    Save An acceleration experimental design method for hybrid-lubrication conformal-contact surface tribological evolution was proposed. The method was based on the concept of “viscosity-reduction acceleration”， where the asperity contact states were preserved while the evolution of tribological behavior was accelerated by increasing the interaction frequency between surface asperities. The approach was validated by Plint TE-92 friction and wear tester.The results show that at the non-accelerated condition （sliding speed is as 0.2 m/s， temperature is as 25 °C， duration is as 20 min） and the corresponding accelerated condition （sliding speed is as 0.4 m/s， temperature is as 47 °C， duration is as 10 min） share the highly consistent values of friction coefficient， and 3D surface parameters Sq and Ssk. It indicates that the wear effect of 10-minute in test with accelerated parameters is equivalent to that of 20-minute in test with non-accelerated parameters. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Construction of Assembly Information Model Based on Assembly Feature Automatic Extraction for STEP Models JIA Kang1, 2, TANG Jing1, 2, REN Dongxu1, 2, WANG Hao1, 2, ZHAO Qiangqiang1, 2, HONG Jun1, 2 China Mechanical Engineering    2025, 36 (01): 123-132.   DOI: 10.3969/j.issn.1004-132X.2025.01.013 Abstract （1979）      PDF（pc） （8528KB）（323）       Knowledge map    Save Assembly information modeling was the foundation of digital assembly and intelligent assembly. However, the manual interactive modeling was inefficient and prone to errors in assembly feature recognition and assembly feature fitting, which was difficult to meet the precise modeling needs of complex mechanical systems. Based on the assembly process information implied by a 3D assembly model, this paper used STEP model files as inputs to study the algorithms for automatic extraction of assembly features and recognition of fitting relationships focused on geometric information. Furthermore, an information reasoning algorithm was proposed for constructing an integrated assembly information model from the perspectives of assembly accuracy modeling and assembly sequence planning. Finally, the effectiveness of the proposed algorithms was demonstrated through the construction of assembly instance information models based on the developed system. Reference | Related Articles | Metrics | Comments（0）

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Flow Field Characteristics of Mesoscopic Impinging Jets under Influences of Wall Micro-defects Rui HONG, Jianjun HU, Yang XIAO, Yaolan JIN, Jing YAO, Xiangdong KONG China Mechanical Engineering    2025, 36 (10): 2215-2223.   DOI: 10.3969/j.issn.1004-132X.2025.10.007 Abstract （263）   HTML （59）    PDF（pc） （4590KB）（322）       Knowledge map    Save In order to study the effects of micro-defects caused by erosion wear and cavitation on flow field law and fluid energy conversion characteristics after long-term service of the nozzle-receiver pilot stage of the jet pipe servo valves. Micro-PIV technology was used to directly test the flow structure and vortex distribution in the square cavity when the original mesoscopic close-range jet impacted the micro-defect target plate. The influences of micro-defect size， shape， and location on vortex morphology and the evolution were investigated， and the underlying mechanism governing the splitting and merging phenomena of vortex cores within a square cavity were elucidated. The results show that the existence of wall micro-defects directly affects the energy transfer and dissipation of the wall jets， leading to a significantly different vortex structure and energy distribution in the jet gap and square cavity than that when there are no defects. As the size of the micro-concave increases， the circular-like vortex pairs in the square cavity on both sides show a tendency to gradually split and move away from the bottom wall. While as the size of micro-convex increases， the cocoon-like vortex pairs in the square cavity on both sides show an evolutionary law of gradually normalization and moving closer to that of the bottom wall. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Simulation and Experimental Study of Temperature for Polishing Aero-engine Blades with Abrasive Cloth Wheel#br# #br# XIAN Chao1, 3, XIN Hongmin2, 3, DAI Hui2, CHENG Qingsi2 China Mechanical Engineering    2025, 36 (04): 802-810.   DOI: 10.3969/j.issn.1004-132X.2025.04.017 Abstract （640）      PDF（pc） （9909KB）（314）       Knowledge map    Save ANSYS software was used to simulate the instantaneous temperature fields in the polishing processes with abrasive cloth wheel using a rectangular heat source loading method. The temperature distribution on the blade surfaces and along the blade thickness direction in the polishing processes was studied, and the influences of processing parameters on the polishing temperature was explored. The results show that as the polishing process progresses, the polishing temperature distribution gradually stabilizes. When the polishing temperature stabilizes, the temperature values of the machined parts of the blade at different depths tend to be consistent, while the temperature of the machining parts decreases continuously along the depth direction; the polishing temperature gradient gradually decreases from the contact area being machined to the machined area; the polishing temperature increases with the increase of spindle speed, the effects of feed speed on the polishing temperature are not significant and the polishing temperature is positively correlated with the tangential polishing forces; the deviation rates between the measured and the simulated temperature values are not more than 10%, indicating that the good consistency and high accuracy of the simulation. Reference | Related Articles | Metrics | Comments（0）

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Research Progresses of Current Carrying Tribological Behavior of Materials under Influences of Service Environment SHEN Mingxue, CHEN Siyang, WU Haihong, XIAO Li, Wang Nenghui, JI Dehui China Mechanical Engineering    2026, 37 (1): 2-13.   DOI: 10.3969/j.issn.1004-132X.2026.01.001 Abstract （338）   HTML （29）    PDF（pc） （29450KB）（313）       Knowledge map    Save The research progresses on current-carrying tribological behavior of materials under service environmental influences were reviewed herein. It was summarized that the tribological performance and the dynamic evolution of electrical arcs under various environmental conditions such as humidity， temperature， atmosphere， crosswind， and air pressure. The mechanism of current-carrying wear under different service environments was clarified， along with the roles of third‑body media （e.g.， water， ice， oxide films） induced by the environments in wear damage and arc erosion of the friction pairs. The intrinsic relationship between external environmental factors and material damage in current-carrying friction pairs was revealed to advance the development of current-carrying friction theory. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Instantaneous Milling Force Modeling and Coefficient Calibration Method of Variable Helical Circular-arc End Mills with Unequal Rake Angle QI Shutao, LI Jiaqi, ZHENG Shucai, XU Jinting, SUN Yuwen China Mechanical Engineering    2025, 36 (04): 681-687,696.   DOI: 10.3969/j.issn.1004-132X.2025.04.004 Abstract （2370）      PDF（pc） （5531KB）（305）       Knowledge map    Save Variable helical end mills with unequal rake angle maight effectively suppress milling chatters, which significantly improved the machined surface quality and simultaneously reduced the risk of tool breakages, however, due to the unequal geometric parameters of each cutting edge, the existing models had difficulty to accurately predict the cutting forces, hence, a new instantaneous milling force modeling and coefficient calibration method were proposed. Firstly, the geometry and position relational expression of the cutting edges for variable helical circular-arc end mills were given, then considering the tool runout and variation of geometrical parameters of cutting edges, an instantaneous uncut chip thickness calculation and element cutting force prediction model was established; Subsequently, a nonlinear optimization method to simultaneously calibrate the cutting force coefficients and tool runout parameters was proposed, and an efficient algorithm for solving the model parameter initial values was also given based on linear least squares and oblique cutting theory. The experimental results show that the amplitude and waveform of predicted cutting forces are consistent with the measured ones with errors of less than 15%, verifying the effectiveness of the proposed model. Reference | Related Articles | Metrics | Comments（0）

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Bearing Fault Diagnosis Method Based on Intensive Distribution Alignment with Open Set Difference LI Can1, 2, WANG Guangbin2, 1, ZHAO Shubiao1, 2, ZHONG Zhixian1, ZHANG Hui1, 2 China Mechanical Engineering    2024, 35 (09): 1622-1633.   DOI: 10.3969/j.issn.1004-132X.2024.09.012 Abstract （1701）      PDF（pc） （8719KB）（300）       Knowledge map    Save In view of the facts that the current transfer learning algorithm was applied to the field of bearing fault diagnosis, there might be unknown fault categories in the target domain, which led to the problems of low recognition accuracy, and an open set domain adaptive method was introduced. Aiming at the problems that the existing open set domain adaptive algorithm paid more attentions to cross-domain alignment and paid little attention to the distribution within the domain when performing distribution alignment, which led to the low recognition rate of unknown categories. A method was proposed based on intensive distribution alignment with open set difference(IDAOD), which integrated cross-domain divergence alignment and intra-domain distribution alienation method. Firstly, the open set nearest neighbor class verification method was used to obtain the pseudo-label of the target domain. Then, the overall divergence matrix of the source domain and the target domain was constructed, and the cross-domain divergence alignment was performed. Based on the distribution adaptation weighted conditional distribution, the spatial distribution of different categories was further alienated in the same domain. Finally, under the framework of structural risk minimization, the loss function constructed was introduced based on the open set difference theory, and the regularization term was introduced to obtain the optimal solution and the new target domain pseudo-label. The feasibility of the IDAOD algorithm was verified by experiments on Office-31 dataset. The fault diagnosis experiments were carried out on CWRU and JNU bearing data sets respectively, and the recognition rate of unknown fault category is higher than that of other comparative open set algorithms. It is verified that the method proposed herein may effectively improve the accuracy of the bearing data set when target sample contains unknown samples. Reference | Related Articles | Metrics | Comments（0）

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Experimental and Molecular Dynamics Simulation for Mechanics Properties of 45 Steel Treated by Plasma Zhaobo PENG, Jinxing KONG, Dongxing DU, Hankun LUO, Hen YUE China Mechanical Engineering    2025, 36 (10): 2190-2197.   DOI: 10.3969/j.issn.1004-132X.2025.10.004 Abstract （594）   HTML （32）    PDF（pc） （2599KB）（294）       Knowledge map    Save To investigate the influences of plasma treatment on the mechanics properties of 45 steel， the changes of mechanics properties of 45 steel before and after treatment were studied by combining experiments and molecular dynamics simulation. The test results show that the hardness and tensile mechanics properties of 45 steel are obviously decreased after plasma treatment. Under the treatment durations of 1， 5 and 10 min， the nano-hardnessis decreased by 12%， 21% and 28% respectively， and the longer the treatment time， the better the modification effect， and the duration of the modification effect is more than 20 h. When the thickness of tensile specimens is as 0.1， 0.15 and 0.2 mm， the tensile strength decreases by 3.3%， 4.5% and 5.3%， and the elongation after fracture decreases by 39.69%， 42.17% and 42.49%， respectively. The molecular dynamics simulation results show that the number and strength of Fe-Fe bonds in 45 steel are reduced after plasma modification， resulting in the reduction of yield strength and surface hardness of the materials， which is basically consistent with the experimental results. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Development and Applications of Metal Laser Additive Manufacturing Technology for High-end Equipment Kai YANG, Lei WANG, Yongkai TANG, Moubin LIU, Ziao GUO China Mechanical Engineering    2025, 36 (09): 2068-2080.   DOI: 10.3969/j.issn.1004-132X.2025.09.019 Abstract （400）   HTML （22）    PDF（pc） （3960KB）（294）       Knowledge map    Save A comprehensive review of the innovative applications and development of laser additive manufacturing technology in high-end equipment manufacturing was provided. Firstly， the basic principles and advantages were introduced， including the ability to achieve integrated manufacturing of complex structures， optimized design of materials and structures， and improvement of component performance. Further， the innovative opportunities brought by laser additive manufacturing technology to high-end equipment manufacturing in aspects were discussed such as new material development， new process innovations， new structures design， and new functions integration. The challenges faced in the applications of laser additive manufacturing technology in high-end equipment manufacturing were analyzed， such as technical difficulties in material system development and new material applications， manufacturing equipment development， online monitoring and quality control technology during the manufacturing processes， and improvement of post-processing technologies. Finally， the future development trends of laser additive manufacturing technology for high-end equipment were outlooked. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

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Spiral Machining Trajectory Planning Method Based on Discrete Point Cloud Construction of Radial Lines WU Jiangsheng, CHAI Xingliang, BO Qile, LIU Haibo, WANG Yongqing China Mechanical Engineering    2025, 36 (04): 697-702,714.   DOI: 10.3969/j.issn.1004-132X.2025.04.006 Abstract （1570）      PDF（pc） （7105KB）（292）       Knowledge map    Save Aiming at the problems that it was difficult to directly generate efficient and accurate continuous smooth tool path trajectories based on discrete point clouds, a method to directly construct radial lines on point cloud and generate spiral machining trajectories through radial line interpolation was proposed herein. For the construction of radial lines, a boundary recognition method was proposed based on feature descriptors to extract boundary points as two end points of the radial lines. Taking the optimal discrete geodesics between two end points on the point cloud as the radial point set, the curvature minimization problems of discrete geodesics were proposed and solved by Newton iteration method. The B-spline curves were used to fit and resampling according to the residual height based on the radial point sets. The radial line interpolation algorithm was proposed to generate the spiral machining trajectory with equal residual height. Finally, an example was given to demonstrate the spiral machining trajectories directly generated by the point cloud data, which fully verified the effectiveness of the proposed method. Reference | Related Articles | Metrics | Comments（0）

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Identification and Evaluation of Key Error Elements in Complex Composite Aviation Componts Assembly Driven by Mechanism and Data Model Fusion GUO Feiyan1, ZHANG Hui2, SONG Changjie1, ZHANG Shuo1 China Mechanical Engineering    2025, 36 (07): 1530-1543.   DOI: 10.3969/j.issn.1004-132X.2025.07.016 Abstract （1745）      PDF（pc） （6423KB）（284）       Knowledge map    Save  In composite assembly of complex aviation products, the factors such as part deformations under loads, numerous parameters and so on were considered. Deformation error source models for key assembly links caused by positioning and clamping, joining and rebounding were analyzed, and the Jacobian sensor matrix representing error transmission relationship was modified to establish assembly error transmission mechanism model. A support vector regression model was established based on assembly error data, a fusion model of mechanism model and data model was gained. With the predication and compensation model for the calculated values of the error mechanism model and the actual deviation, a Sobol sensitivity analysis method was adopted to calculate the global sensitivity coefficients of different assembly error links, and the key error elements affecting assembly accuracy was identified. Finally, the assembly of wing box component was taken as an example to prove the effectiveness of the proposed method. Reference | Related Articles | Metrics | Comments（0）

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Influences of Rotational Speed and Flow Rate on Pressure Pulsations of a Rim-driven Axial Flow Pump Mengjie CHEN, Zhuo ZHANG, Wu OUYANG, Chenxing SHENG, Bao LIU, Wei LIU China Mechanical Engineering    2025, 36 (10): 2198-2206.   DOI: 10.3969/j.issn.1004-132X.2025.10.005 Abstract （355）   HTML （34）    PDF（pc） （5874KB）（278）       Knowledge map    Save A novel RDP generated pressure pulsations during operations， which might negatively impact pump performance and system stability. The numerical simulation was employed to analyze the external characteristics and internal flow patterns of RDP under different rotational speeds and flow conditions. Utilizing POD， the main energy modes were extracted through spatiotemporal feature decomposition to investigate the influences of rotational speed and flow rate on the pressure pulsation at the trailing edges of the impeller blades， revealing the relationship between nonlinear dynamics and fluid-structure interaction phenomena. The results show that each rotational speed corresponds to a distinct optimal operating point， with the optimal point shifting towards lower flow rates as the rotational speed decreases. Moreover， the pressure pulsations are predominantly governed by nonlinear dynamics behavior， with nonlinear interaction effects between the impeller blades and guide vanes becoming more pronounced at lower rotational speeds and higher flow rates. Table and Figures | Reference | 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 （1041）      PDF（pc） （6000KB）（276）       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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Influence Law and Mechanism of Geometric Parameters on Wrinkling Characteristics of Hollow Aluminum Profiles in Stretch-Bending#br# LIU Zhiwen1, 2, LEI Chong1, SUN Kaibo1, OUYANG Basheng1, LI Luoxing2, LIU Xiao3, LI Fazhi1 China Mechanical Engineering    2025, 36 (05): 1083-1093.   DOI: 10.3969/j.issn.1004-132X.2025.05.020 Abstract （1923）      PDF（pc） （8620KB）（267）       Knowledge map    Save Based on the plate and shell theory， the expression of wrinkling energy and external force work functions of hollow aluminum profiles in stretch-bending were derived. Combined with the energy criterion， the theoretical prediction model of wrinkling was established for hollow profiles in stretch-bending and the accuracy of model was verified by bending experiments. The formation mechanism of wrinkling defects in stretch-bending of hollow profiles was revealed and the influences of geometric parameters on wrinkling limit and morphology were quantitatively studied. The results show that the theoretical predictions of the number and height of wrinkling under three different bending radii are in good agreement with those of the experimental ones. The maximum differences are as 1.2 and 0.55 mm， respectively， with relative errors of 16.93% and 11.28%， respectively. The growth rate of external force work in the bending stages is greater than that of wrinkling energy. With the increase of bending time， the external force work is greater than the wrinkling energy， resulting in the appearance of wrinkling instability. With the increase of thickness-to-height ratio and thickness-to-width ratio of the profiles， the wrinkle ratio and wrinkling number decrease， while the wrinkling limit and wrinkling height increase. With the increase of the aspect ratio， the wrinkle ratio and wrinkle height increase， while the wrinkling limit and wrinkling number decrease. The wrinkling limit might be increased by adding inner reinforcement rib in the profile cavities， while the wrinkling number increases and the wrinkling height decreases.  Reference | Related Articles | Metrics | Comments（0）

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China Mechanical Engineering    2024, 35 (05): 1-.   Abstract （371）      PDF（pc） （110765KB）（252）       Knowledge map    Save Related Articles | Metrics | Comments（0）