Most Read articles

Published in last 1 year |  In last 2 years |  In last 3 years |  All

All

Please wait a minute...


For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails

Select

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 （2274）      PDF（pc） （8675KB）（183）       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）

Select

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 （2132）      PDF（pc） （5531KB）（104）       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）

Select

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 （1899）      PDF（pc） （5744KB）（66）       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）

Select

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 （1879）      PDF（pc） （25364KB）（182）       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）

Select

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 （1846）      PDF（pc） （7836KB）（75）       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）

Select

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 （1727）      PDF（pc） （8620KB）（71）       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）

Select

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 （1720）      PDF（pc） （7015KB）（142）       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）

Select

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 （1622）      PDF（pc） （8056KB）（100）       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）

Select

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 （1490）      PDF（pc） （6423KB）（42）       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）

Select

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 （1382）      PDF（pc） （7105KB）（77）       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）

Select

Study on In-plane Shear Behavior and Interaction Mechanism of Flexible Elastic Composite Lattice Structures NIU Guofa1, JI Xiaogang1, 2, WANG Wei1, WANG Guangyang1 China Mechanical Engineering    2025, 36 (05): 1103-1110.   DOI: 10.3969/j.issn.1004-132X.2025.05.022 Abstract （1366）      PDF（pc） （8492KB）（56）       Knowledge map    Save The shear behavior and interaction mechanism of composite lattice structures were studied under in-plane shear loads by tests and numerical simulations. The damage failure courses and failure modes of matrix body centered cube(BCC) structures were analyzed experimentally. Using BCC cell structure as matrix, the influences of the diameter of chimeric structures on shear strength and shear modulus of composite structures were investigated by means of chimeric structure. Finally, the reliability of finite element analysis was verified by face centered cubic(FCC) structure tests, and the interaction mechanism of FCC-BCC structures was explored under in-plane shear loads. The testing results show that the mosaicism amang structures enhances the bearing capacity of the composite lattice structures, and influences the strains of the composite structures. The ultimate shear strength of FCC-BCC and simple cube-body centered cube(SC-BCC) are as 159% and 80% higher than that of the matrix respectively when the diameter size of the structural rods are both 0.45 mm. Reference | Related Articles | Metrics | Comments（0）

Select

Effects of Glass Fiber Mass Fraction on W-PACIM Pipes of Long Glass Fiber Reinforced Polypropylene LIAO Qiansheng1, 3, LIU Hesheng2, KUANG Tangqing2, LIU Jiahao2, ZHANG Wei2 China Mechanical Engineering    2025, 36 (06): 1329-1337.   DOI: 10.3969/j.issn.1004-132X.2025.06.020 Abstract （1331）      PDF（pc） （6799KB）（32）       Knowledge map    Save To study the effects of glass fiber mass fraction on W-PACIM pipes with long glass fiber reinforced polypropylene as the outer material and pure polypropylene as the inner material, the influences of glass fiber mass fraction on the residual wall thickness, the orientation distribution of glass fibers and the pressure resistance of the pipes were analyzed by experimental methods. The results show that with the increases of glass fiber mass fraction, the total residual wall thickness of the pipes decreases first and then increases. The outer layer of the pipes may be divided into near the mold wall layer, the middle layer and the near interface layer according to the distribution characteristics of the glass fiber orientations, the orientation of the glass fiber along the melt flow direction increases gradually from the outside to the inside, the uniformity of the distribution of the outer glass fiber decreases with the increase of glass fiber mass fraction. The pressure resistance of pipes increases first and then decreases, when the glass fiber mass fraction is 20%, the pressure resistance of pipes is the best. Reference | Related Articles | Metrics | Comments（0）

Select

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 （1329）      PDF（pc） （9510KB）（183）       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）

Select

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 （1286）      PDF（pc） （7393KB）（205）       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）

Select

Thermal Image Input-based ResNet Method for Thermal Error Modeling of Machine Tool Spindles Mingfan LI, Long YANG, Sheng LI, Huan GUO, Guoqiang FU China Mechanical Engineering    2025, 36 (09): 2057-2067.   DOI: 10.3969/j.issn.1004-132X.2025.09.018 Abstract （1271）   HTML （1）    PDF（pc） （5627KB）（86）       Knowledge map    Save To achieve a high-precision and highly generalizable thermal error model of machine tools， a thermal image input-based ResNet method was proposed for thermal error modeling of CNC machine tool spindles. A thermal image dataset labelled was constructed with thermal error rounding， and a ResNet-based classification model was trained for thermal error prediction using thermal images as inputs. Considering the regression characteristics of the machine tool thermal error time series， a regression output layer was constructed by integrating the probabilities of different classification labels from the classification output layer in a weighted manner， enabling thermal error regression prediction without retraining. The deep features of thermal images and the classification performance of the ResNet model were visualized， confirming the effectiveness of ResNet in feature extraction and strong classification ability. Finally， the ResNet model was compared with GoogLeNet and VGGNet models under different operating conditions， demonstrating the high accuracy and generalization of the ResNet-based thermal error classification and regression models. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

Select

Research on Mechanism Analysis and Online Monitoring System of Camshaft High-speed Grinding Burns Zhaohui DENG, Rongjin ZHUO, Jingqiang CHEN, Jimin GE, Lishu LYU, Wei LIU China Mechanical Engineering    2025, 36 (08): 1784-1795.   DOI: 10.3969/j.issn.1004-132X.2025.08.014 Abstract （1234）   HTML （2）    PDF（pc） （5261KB）（48）       Knowledge map    Save The high-speed grinding of the non-circular contours of the camshafts was prone to grinding burns， resulting in a decrease in surface quality and service life and even scrapping. Therefore， the mechanism analysis and online monitoring system of camshaft high-speed grinding burns were studied. The influences of processing parameters on grinding burns were discussed. A grinding burn's quantitative evaluation method was proposed by surface morphology and hardness.Frequency and time-frequency domain analysis methods carried out the signal processing and feature extraction. The relationship between the sensing signals and grinding burns was analyzed. The AE （acoustic emission） signal features with a high correlation with grinding burn were extracted based on ReliefF. The monitoring model of grinding burn was established based on GA-SVM（genetic algorithm-support vector machine）. And it was verified by experiments. The online monitoring system of camshaft high-speed grinding burns was developed and applied. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

Select

Thin-walled Workpiece Milling Deformation Error Prediction Based on Multi-source Information Fusion and Ensemble Learning YIN Jia1, ZHENG Jian2, LIU Yao3, JIA Baoguo1, DUAN Xiaorui1 China Mechanical Engineering    2025, 36 (06): 1261-1268.   DOI: 10.3969/j.issn.1004-132X.2025.06.013 Abstract （1192）      PDF（pc） （5304KB）（40）       Knowledge map    Save In practical machining processes, the dimensional accuracy of thin-walled workpiece was significantly affected by multiple factors including cutting forces, forced vibrations, chatter phenomena, geometric characteristics of workpiece and material properties, rendering deformation prediction and control particularly challenging. A multi-source information fusion method for deformation error prediction in thin-walled workpiece milling processes was developed. Machining parameters, vibration signals, and other relevant data were integrated to establish a deformation error prediction model through Stacking ensemble learning methodology, with comprehensive experimental validation performed. Comparative analyses reveal that the constructed model demonstrates superior robustness, higher accuracy, and enhanced practicality when compared with conventional data-driven prediction methods. Reference | Related Articles | Metrics | Comments（0）

Select

Ultra-precision Turning Alignment Error Compensation Technology in Multi-axis Simultaneous Operations YUAN Jiabin, GUO Xipeng, LI Rong, YIN Shaohui China Mechanical Engineering    2025, 36 (07): 1397-1406.   DOI: 10.3969/j.issn.1004-132X.2025.07.001 Abstract （1185）      PDF（pc） （9879KB）（66）       Knowledge map    Save To address the issues of ineffective compensation for aspheric machining figure errors, an XZB three-axis ultra-precision machining method was proposed. The impact of errors in tool alignment, tool radius and the deviation of tool tip relative to the B-axis rotation center on workpiece surface accuracy was analyzed, and the corresponding compensation methods were presented. Turning experiments of nickel-plated convex aspherical workpieces were conducted. Figure errors of the workpieces were reduceed from 0.6774 μm to 0.0749 μm, with the XZB three-axis linked turning method. Experimental results show that the XZB three-axis linked turning process significantly improves the surface shape accuracy and surface quality of small-diameter aspherical surfaces, compared with the XZ two-axis linked turning method. Reference | Related Articles | Metrics | Comments（0）

Select

Generation Method of Milling Paths of Open Blisk Channels Based on Parameter Mapping HAN Jiang1, 2, ZHANG Wenqiang1, 2, TIAN Xiaoqing1, 2, XIA Lian1, 2 China Mechanical Engineering    2025, 36 (04): 688-696.   DOI: 10.3969/j.issn.1004-132X.2025.04.005 Abstract （1115）      PDF（pc） （9035KB）（64）       Knowledge map    Save A machining strategy for variable layer thickness with layered surfaces was proposed to address the rough machining issues of the channels across the entire blisk components. Considering the characteristics of the variation in the width of the channels across the entire blisk components, the geodesic offset was used to determine the toolpath boundaries on both sides of the channels, and the step size and the number of paths were determined. A planning method for the longitudinal milling path along the channels was proposed, and then the tool axis vector of the channel boundaries is calculated, and the tool axis vector of the middle cutter positions of the channel boundaries is calculated by quaternion interpolation. The calculation results show that, compared with the conventional uniform layering method using the blisk hub rotary surface offset or the blisk covering rotary surface offset, the variable layer thickness surface delamination may better adapt to the surface changes from the covered rotary surface to the hub rotary surface, the surface quality of the blades is ensured, with the advantage of a uniform machined blade surface allowance, and the feasibility of the algorithm was verified through machining examples.  Reference | Related Articles | Metrics | Comments（0）

Select

C-warping Mechanism and Treatment Strategies in Leveling Processes of Strip Steels YANG Yonghui1, ZHANG Ji1, TAN Hailong1, NIU Baicao1, BAI Zhenhua1, 2, 3 China Mechanical Engineering    2025, 36 (06): 1345-1351.   DOI: 10.3969/j.issn.1004-132X.2025.06.022 Abstract （1112）      PDF（pc） （1401KB）（27）       Knowledge map    Save  In order to solve the problems of C-warping defects in strip steels in the leveling processes, the processing parameters in the strip leveling processes were optimized, and a set of C-warping prediction and treatment strategies for strip steels were developed. The formation mechanism of C-warping was analyzed from three aspects: rolling, processing lubrication systems and the influences of anti-wrinkle rollers and anti-trembling rollers on the forces of strip steels. The stress distribution of the horizontal direction of the outlet strips in the thickness was obtained, based on the stress analysis of the strips under the assumption of half-plane infinite body， the maximum and minimum transverse elongation in the thickness direction of the strips were obtained, and the height of the C warp of the strips was obtained through the geometric relationship. A set of optimal height settings of anti-wrinkle rollers and anti-trembling rollers were sought to minimize the objective function of the comprehensive control, and the elongation in the direction of strip thickness was controlled, so as to reduce C-warp. The model and treatment strategies were applied to a leveling unit in China, and the prediction errors of C warping height are controlled within 10%, and the maximum warpage ranges of the unit are reduced from 1.4~6.5 mm to 0.9~4.5 mm. The results show that the C warpage prediction and treatment strategy meet the production demands, and the warpage values are significantly reduced, which reduces the repair rate caused by warpages. Reference | Related Articles | Metrics | Comments（0）

Select

Study on Thickness Distribution of Single Point Incremental Hydroforming of Complex Shaped Parts SHANG Miao, LI Yan, SHAN Shunkun, YANG Mingshun China Mechanical Engineering    2025, 36 (06): 1338-1344.   DOI: 10.3969/j.issn.1004-132X.2025.06.021 Abstract （1075）      PDF（pc） （10225KB）（45）       Knowledge map    Save To analyze and enhance the performances of single point incremental forming for complex shaped parts, a new process combining SPIF and hydroforming was presented for manufacturing multi-featured parts with spire structures. The forming processes of the target parts were designed, the theoretical prediction model of thickness was established, and the effects of different hydraulic parameters on the thickness distribution of the target parts in different forming stages were analyzed. The experimental results show that complex shaped parts may be formed using the new processes and appropriate hydraulic pressures; the geometric errors between the experimental and theoretical profiles may be reduced from 11.44% to 5.18% with assistance compared to SPIF without hydraulic assistance; the thickness distribution patterns are related to the assisted pressure, forming heights, forming shape, etc., and the established theoretical model may be used to predict the thickness distribution of complex shaped parts. Reference | Related Articles | Metrics | Comments（0）

Select

Influences of Differential Lubrication on Forming Quality for 5A02 Aluminum Alloy T-shape Tubes XU Yong1, 2, 3, ZHANG Chi1, XIE Wenlong2, 3, XIA Liangliang4, YANG Baocheng2, 3, ZHANG Shihong2, 3, HUANG Xinyue5, WANG Shengcheng5 China Mechanical Engineering    2025, 36 (05): 1094-1102,1131.   DOI: 10.3969/j.issn.1004-132X.2025.05.021 Abstract （1039）      PDF（pc） （12824KB）（53）       Knowledge map    Save  In order to improve the forming quality of T-shape tubes, a method of differential lubrication was proposed by using hydroforming. The advantages of differential lubrication were verified by finite element simulation compared with traditional lubrication. Based on the fluidity of materials, the tensile stress and compressive stress of axial and circumferential elements of T-shape tubes were extracted during deformation. The influences of the area of the differential lubrication zones on the forming quality were analyzed. The results show that compared with the traditional lubrication method, the differential lubrication may effectively reduce the wall thickness thinning rate of the sides and tops of the T-shape tubes. Differential lubrication also may reduce the amount of side feed to reduce the risk of wrinkling. With the increasing of lubrication area in the bulging zones, the axial tensile stress of the arm element is gradually reduced, and the thinning rate of the arm sides of the T-shape tubes is reduced. With the increasing of the artificial roughing areas in the non-bulging zones, the axial compressive stress of the T-shape tubes sidewall element decreases, but the circumferential  tensile stress  increases gradually, and the material is more likely to flow to the transition zone of T-shape tubes, avoiding material accumulation in the middle of the tubes, thus reducing the risk of wrinkling. The research may provide technical support and theoretical reference for the forming of T-shape tubes. Reference | Related Articles | Metrics | Comments（0）

Select

Establishment and Influences of Critical Wrinkling Criterion of Sheet Metals Considering Thickness Stress DU Bing1, 2, LI Yang1, 2, LIU Fenghua1, 2, DONG Mingxin1, 2, WAN Yufan1, 2, ZHONG Qingshuai1, 2 China Mechanical Engineering    2025, 36 (05): 1074-1082.   DOI: 10.3969/j.issn.1004-132X.2025.05.019 Abstract （1009）      PDF（pc） （9174KB）（84）       Knowledge map    Save Wrinkling instability was one of the main technical challenges affecting the precise plastic forming of thin-walled parts. The stress state in the thick direction had a great influence on the forming limit of the sheet metals during the sheet forming processes. In view of the above problems， the wrinkling instability of sheet metals in plastic forming processes was studied under different thickness stress conditions. The Buckle-Dynamic algorithm in ABAQUS software was combined with solid element modeling to establish a numerical analysis model of liquid-filled compression of fan-shaped parts， and the accuracy of the simulation algorithm was verified by tests. According to the wrinkling bifurcation theory and numerical analysis results， a method was adopted for defining the critical wrinkling time of the plates considering the thickness stress， and the critical wrinkling limit curve was established under the compression conditions of the plates. The influences of thickness stress on the compression wrinkling behaviors， wrinkle resistances and the positions of critical wrinkling limit curve in space of fan-shaped parts were discussed. The results show that the applications of thick stress may improve the wrinkle resistances of the sheets and improve the forming quality， which provides useful reference and experimental basis for the selection of sheet metal forming parameters and the trial production of typical parts.  Reference | Related Articles | Metrics | Comments（0）

Select

Research Status and Development Trends of Failure Modes, Effects, and Criticality Analysis for CNC Machine Tool Reliability TIAN Hailong1, 2, SUN Yuzhi1, 2, YANG Zhaojun1, 2, LIU Zhifeng1, 2, CHEN Chuanhai1, 2, HE Jialong1, 2 China Mechanical Engineering    2025, 36 (07): 1430-1441.   DOI: 10.3969/j.issn.1004-132X.2025.07.005 Abstract （849）      PDF（pc） （1000KB）（93）       Knowledge map    Save FMECA played an important role in reliability maintenance of CNC machine tools. Current researches focused on 4 aspects: comprehensive evaluation of multiple factors, integration of multi-source hierarchical information, integration of multiple analysis methods, and dynamic characteristic modeling. By systematically combination of existing research results, the advantages and existing problems of the 4 aspects were analyzed. Evolution path of machine tool failure modes, effects and criticality analysis were explained by the integration of the characteristics of industrial needs, which provides a theoretical basis for building a high-precision machine tool reliability evaluation system. Reference | Related Articles | Metrics | Comments（0）

Select

Simulation and Experimental Analysis for Active Vehicle Interior Noise Control Based on FFxLMS WANG Jian1, ZHANG Ming1, LIU Song1, QUAN He1, FENG Chao1, ZHANG Zhe2 China Mechanical Engineering    2025, 36 (04): 850-856.   DOI: 10.3969/j.issn.1004-132X.2025.04.022 Abstract （817）      PDF（pc） （9754KB）（70）       Knowledge map    Save In view of the problems such as huge computational counts, low convergence speed and poor stability of the widely-used time-domain feedforward adaptive algorithm(TFxLMS) for active vehicle interior noise control, a FFxLMS was proposed based on fast Fourier transform(FFT) and block computation. The strengths and weaknesses of the FFxLMS algorithm and the TFxLMS algorithm were compared in terms of the noise reduction, computational count, convergence speed, and stability. Furthermore, the numerical findings were experimentally validated. The results show that the FFxLMS algorithm has advantages in noise reduction, computational count, convergence speed and stability. Reference | Related Articles | Metrics | Comments（0）

Select

Research on Differential Steering Mechanism Based on Tire Cornering Biaofei SHI, Xiaoming YE, Haoyu LYU, Feng LAI China Mechanical Engineering    2025, 36 (10): 2224-2231.   DOI: 10.3969/j.issn.1004-132X.2025.10.008 Abstract （694）   HTML （10）    PDF（pc） （1816KB）（72）       Knowledge map    Save Differential steering based on tire cornering suited low-speed， large steering radius scenarios of distributed drive electric vehicles（DDEV） without steering mechanisms. In order to study the mechanism of differential steering based on tire cornering， a 7-degree-of-freedom DDEV dynamic model with no steering mechanism and PAC2002 tire model were established. Then， the formation mechanism of differential steering was analyzed and a systematic analysis method from the input of differential longitudinal force to the output of vehicle steering radius of differential steering was proposed by considering the tire force longitudinal-lateral-coupling characteristics. Leveraging the proposed systematic analysis method， the stability of differential steering and the influences of differential longitudinal force， vehicle parameters and tire characteristics on steering radius were studied. Finally， a Carsim/Simulink joint simulation platform was established to simulate differential steering under different influencing factors. The results show that within the range of tire cornering， the larger the differential longitudinal force， the larger the ratio of track width to wheelbase， and the smaller the tire lateral stiffness， the smaller the steering radius. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

Select

Integrated Design Technology for New Energy Vehicle Power Battery Systems SHI Peicheng1, SHAN Zixian1, ZHU Hailong1, HAI Bin2, WANG Lei2, LU Fayan2 China Mechanical Engineering    2025, 36 (07): 1611-1623.   DOI: 10.3969/j.issn.1004-132X.2025.07.024 Abstract （690）      PDF（pc） （6886KB）（57）       Knowledge map    Save An integrated design technology of power battery systems for new energy vehicles was elaborated, and the advantages in space utilisation, range, and cost control were shown by analysing the technology such as moduleless, battery chassis integration and battery body integration. Other typical battery technology which promoted the development of automotive industry through structural innovation, thermal management optimisation and fast charging solutions were explored. The development directions of power battery system integration technology were outlooked in terms of intelligent integration, sustainable materials, and standardisation. Reference | Related Articles | Metrics | Comments（0）

Select

Vehicle Lateral Control Strategy Integrating Road Curvature Feedforward Xinyou LIN, Zhongwei JIN, Yunliang TANG China Mechanical Engineering    2025, 36 (11): 2774-2782.   DOI: 10.3969/j.issn.1004-132X.2025.11.036 Abstract （631）   HTML （0）    PDF（pc） （2868KB）（33）       Knowledge map    Save Aiming at the problems of low tracking accuracy of autonomous vehicles in the road with large curvature curves， the influences of road curvature on the lateral control strategy were focused， the lateral control strategy was improved and optimized based on the traditional model predictive control（MPC） algorithm from three aspects of vehicle model modeling， yaw stability and time domain optimization， respectively. The road curvature was integrated into the vehicle model， and an error dynamics model with curvature feedforward was established. And then， a lateral control strategy was designed based on curvature feedforward MPC algorithm. Then， a lateral stability constraint consisting of lateral vehicle speed and steady-state lateral angular velocity was added to the strategy to enhance the lateral stability of the vehicles under high curvature conditions. A MAP map was established based on genetic algorithm to optimize the prediction and control time domains of the strategy， taking into account the relationships among vehicle speed， road curvature and time domain. Simulation analysis was conducted， and the results show that the improved lateral control strategy may effectively improve the path tracking precision and lateral stability of the vehicles. Finally， the effectivenesses of the curvature feedforward MPC strategy were verified through real vehicle road tests. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

Select

Vehicle Yaw and Roll Stability Control Based on Dynamic Output Feedback YIN Xizhi1, 2, 3, HU Sanbao1, 2, 3, FENG Zhiyong1, 2, 3 China Mechanical Engineering    2025, 36 (07): 1453-1462.   DOI: 10.3969/j.issn.1004-132X.2025.07.007 Abstract （612）      PDF（pc） （3520KB）（39）       Knowledge map    Save In order to improve the yaw and roll stability of in-wheel motor drive electric vehicles under extreme conditions such as high speed and low adhesion, a 3-DOF multi-cell model of vehicle lateral dynamics was established, and a robust layered controller was proposed. The local optimal solution of the upper-level reduced-order dynamic output feedback controller was obtained by iterative search, with the demands for the pole configuration and H∞ performance constraints at the same time. With the optimization objective of minimizing the comprehensive tire load rate, the optimal torque of the lower four wheels was obtained. Simulink and CarSim co-simulation results show that this control strategy may significantly improve vehicle stability under different working conditions, and maintain robustness to system parameter variations and external disturbances.  Reference | Related Articles | Metrics | Comments（0）

Select

Intelligent Vehicle Trajectory Planning Based on Spatio-temporal Risk Fields Huifang KONG, Chenshun WANG, Qian ZHANG, Tiankuo LIU China Mechanical Engineering    2025, 36 (10): 2463-2471.   DOI: 10.3969/j.issn.1004-132X.2025.10.036 Abstract （604）   HTML （0）    PDF（pc） （2976KB）（33）       Knowledge map    Save Aming to describe and avoid different dimensions of risks faced by intelligent vehicles， a two-layer trajectory planning method was proposed based on spatio-temporal risk fields. Traffic elements were divided into abstract elements and concrete elements， the spatial-temporal risk fields of abstract elements based on Gaussian distribution function and concrete elements based on spatial vector were established respectively to represent the environmental risks faced by intelligent vehicles in three dimensions： vertical， horizontal and temporal. Additionally， the trajectory planning problem of intelligent vehicles was divided into path and speed dual planning problem. The longitudinal-lateral dimension risk and longitudinal-temporal dimension risk were accordingly applied to dynamic planning cost function. Then， the path and speed with the comprehensive lowest cost were calculated， and combined with quadratic programming algorithm， the path and velocity were further optimized to obtain the final trajectory. Simulation results demonstrate that the proposed methodology may effectively characterize spatio-temporal driving risks across diverse scenarios while generating constraint-satisfying trajectories， thereby significantly enhance road driving safety. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

Select

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 （602）      PDF（pc） （17686KB）（368）       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）

Select

Rigid-flexible Coupling Identification of MDOF Excitation for Door Limiter and Shaking Optimization of Window Frame during Closing Chengzhan LI, Pengcheng GUO, Congchang XU, Luoxing LI, Yongfu XIAO, Shuxia JIANG China Mechanical Engineering    2025, 36 (11): 2792-2800.   DOI: 10.3969/j.issn.1004-132X.2025.11.038 Abstract （499）   HTML （1）    PDF（pc） （3581KB）（28）       Knowledge map    Save Aiming at the problems that traditional NVH analysis struggled to accurately extract and predict the dynamic excitation and response of vehicle doors during rotation， a new method was proposed and applied to vibration transfer function analysis based on rigid-flexible coupling for identifying MDOF excitation. Taking the abnormal shaking of the window frame during door closing in a specific vehicle model as the research objective， a whole vehicle rigid-flexible coupling model was established by using multibody dynamics method. The MDOF acceleration dynamic excitation at the limiter installation points was extracted for transfer function analysis. The comparison between simulation and testing results shows that consistent peak values of vibration acceleration are detected at 12 Hz， which verifies the accuracy of the rigid-flexible coupling model. Then， the key factors affecting window frame shaking during door closing were analyzed via simulation， identifying the limiter structure as the core optimization target. An optimization scheme was proposed， and vibration transfer function analysis under the extracted dynamic excitation shows that the optimized limiter structure may significantly reduce the window frame shaking level during door closing. Table and Figures | Reference | Related Articles | Metrics | Comments（0）

Select

Study on Absolute Linear Time-grid Displacement Sensors with  Multi-frequency Magnetic Field Coupling YANG Jisen1, 2, 3, YUAN Junsong1, 3, XIU Fu1, 3, LIU Jiacheng1, 3, ZHANG Xiaolong1, 3 China Mechanical Engineering    2025, 36 (05): 889-897.   DOI: 10.3969/j.issn.1004-132X.2025.05.001 Abstract （489）      PDF（pc） （8864KB）（192）       Knowledge map    Save Aiming at the problems of mutual crosstalk among magnetic fields affecting the measurement accuracy of the sensors and reducing the signal-to-noise ratio when the excitation frequency of two code channels of a dual-row planar magnetic field sensor was the same， a multi-frequency magnetic field coupled absolute linear time-grid displacement sensor design scheme was proposed， which achieved the solution to the problems of eliminating the crosstalk of the magnetic fields among the code channels while solving the absolute displacement. The sensor was divided into fixed scale and dynamic scale， both using double-layer alternating structure， fixed scale using two columns of incremental code channel combination， divided into fine and coarse machines， the pairs of poles of two rows of excitation coils were two integers of the reciprocal relation， the absolute displacement measurement was realized by using the pairs of poles within the displacement difference. Precision machine measurement channel and rough machine measurement channel were input  different frequencies of the excitation current signals at the same time，  the precision machine was input the 1 MHz high-frequency current signals， the high-frequency excitation current signals might effectively enhance the inductive signals， improve the signal-to-noise ratio of the electrical processing system. Through the method of outlier frequency reduction， the sensor resolution was improved， which effectively solved the problems that it were difficult to reconcile the signal-to-noise ratio enhancement of the signals by increasing the frequency of the excitation signals and the high resolution of the sensors. Theoretical validation and error analysis of the sensors were carried out through electromagnetic simulation analysis. Finally， the experimental platform was built to carry out prototype experiments， and the experimental results show that the absolute sensor structure with multi-frequency magnetic field coupling effectively eliminates the magnetic field crosstalk between the fine and coarse machines， and the signal-to-noise ratio of the sensors is improved， with measurement errors are less than ±17.34 μm in the measurement range of 140 mm.  Reference | Related Articles | Metrics | Comments（0）

Select

Reconstruction of Magnetic Field Responses Caused by Rail Surface Cracks with Alternative Current Excitation WANG Chi1, 2, ZHOU Yu1, 2, WENG Zhiyi1, 2 China Mechanical Engineering    2025, 36 (04): 830-839.   DOI: 10.3969/j.issn.1004-132X.2025.04.020 Abstract （462）      PDF（pc） （18289KB）（52）       Knowledge map    Save As the response laws of the perturbed magnetic field in ACFM to rail RCF crack morphology parameters remained unclear, a novel method was proposed for functional reconstruction between the ACFM perturbed magnetic field and rail RCF crack parameters. The ACFM calculation models were established based on multiple field tests of surface length, ellipse ratio, and internal angle of RCF cracks in heavy-haul railway rails throughout their full life cycle. The perturbed magnetic field above RCF cracks with different parameters was numerically calculated using the ACFM model. The relationship between RCF crack parameters and the perturbed magnetic field was systematically analyzed. Through fitting and evaluation of the perturbed magnetic field's response to the spatial morphology parameters of RCF cracks, the functional expression of the response laws was reconstructed. The results demonstrate that the ACFM response to rail RCF crack parameters is synthetically characterized. The peak value of magnetic field x-component is observed to increase linearly with the surface length and nonlinearly with the internal angle of RCF cracks. Conversely, a nonlinear decrease may be identified as the ellipse ratio of RCF cracks increases. These variations are effectively described by polynomial functions. The change rules between the perturbed magnetic field and RCF crack parameters may be functional reconstructed. The determination coefficient between the reconstructed results and the perturbed magnetic field is found to exceed 0.99, while the sum of squared errors(SSE) and root mean squared errors(RMSE) are constrained to less than 0.001 15 and 0.003, respectively.  Reference | Related Articles | Metrics | Comments（0）

Select

Numerical and Experimental Study on Effects of Rivet Crack on Mechanics Properties of Self-piercing Riveted Joints CHENG Aiguo1, WANG Chao1, YU Wanyuan2, HE Zhicheng1 China Mechanical Engineering    2025, 36 (02): 197-208.   DOI: 10.3969/j.issn.1004-132X.2025.02.002 Abstract （457）      PDF（pc） （22151KB）（100）       Knowledge map    Save The rivet cracks generated in joining high-strength steels using SPR were simulated through finite element model, and the effects of rivet crack depth, crack position, and crack quantity on the mechanics properties of steel-aluminum SPR joints were systematically investigated. Firstly, a 2D axisymmetric numerical model was established using LS-DYNA software to simulate the SPR processes, and the accuracy of the numerical model was validated by comparing experimental and simulated joint cross-profiles. Secondly, a 2D-3D finite element model generation method was employed to establish a 3D numerical model of SPR joints to simulate the mechanics properties of SPR joints. The fracture parameters of rivets were calibrated using LS-OPT software. The developed 3D numerical model of SPR joints could accurately predict the mechanics properties of SPR joints. The results of parametric study indicate that the mechanics properties of the SPR joints decrease with increasing crack depth and gradually increase as the external crack position moves downward, but the internal crack has minimal influence. When multiple cracks exist in the rivets, the mechanics properties of the joints depend on the weakest cracks and are independent of the quantity. Reference | Related Articles | Metrics | Comments（0）

Select

Design of Scale-changeable Pantograph Legs for Heavy-duty Robots SUO Zhe, LI Xiang, LIU Jianfeng, WANG Jixin China Mechanical Engineering    2025, 36 (02): 191-196.   DOI: 10.3969/j.issn.1004-132X.2025.02.001 Abstract （449）      PDF（pc） （7951KB）（207）       Knowledge map    Save The motion characteristics of the 2 DOF(degree-of-freedom) scale-changeable pantograph leg mechanisms were analyzed, different designs for scale change were compared. A scale-changeable pantograph leg with a nonlinear length adjustment mechanisms was proposed. The length of the thigh and shank link could be adjusted with a single driver according to the nonlinear proportion relation. Thus, the scale could be changed while preserving the pantograph mechanism properties. The scale-changeable pantograph leg may change the scale without disassembling, adjust the foot working space and the carrying capacity of the robots. Reference | Related Articles | Metrics | Comments（0）

Select

Inverse Solution for TC4 Residual Stress Gradient Distribution in Four-axis Milling with Tapered Ball-end Cutters ZHOU Jinhua1, 2, QI Qi1, 2, REN Junxue1, 2, ZHAN Mei1, 2 China Mechanical Engineering    2025, 36 (04): 770-779.   DOI: 10.3969/j.issn.1004-132X.2025.04.014 Abstract （445）      PDF（pc） （7217KB）（84）       Knowledge map    Save The internal and external profile finishing of the metal reinforcing edges of the leading edge of large composite fan blades for commercial aero-engines was accomplished by four-axis milling with a customized taper ball-end cutter, and the machining residual stresses introduced at this stage often caused excessive bending and torsional deformations leading to dimensional overshoots of the parts. For the four-axis milling of titanium alloy TC4 with taper ball-end cutter, an inverse identification method of milling residual stress gradient distribution was proposed based on the deformation tests of thin plate machining herein. The hyperbolic tangent models were used to parametrically characterize the milling residual stress gradient distribution, and the solution of the residual stress gradient distribution was converted into the inverse solution of two pending coefficients k and ω. The model coefficient k was determined by testing the residual stress on the machined surfaces of the titanium alloy specimen blocks, and the model coefficient ω was inversely solved by testing the bending deformation deflection of milled titanium alloy thin plates, then the residual stress gradient distribution curve was determined. Four groups of titanium alloy TC4 test block milling validation experiments were carried out, and the test results show that the average prediction accuracy of the milling residual stress gradient distribution is as high as 99.35%. Compared with the traditional X-ray test method, the proposed method avoids the use of electrolytic corrosion stripping to test the subsurface residual stresses, and also takes into full consideration the non-uniformity of the distribution of milling residual stresses on the machined surfaces, namely the problem of the dispersion of milling residual stresses. Reference | Related Articles | Metrics | Comments（0）

Select

Tip-trajectory Following Algorithm for Snake-arm Robots Based on Dynamics Denoising Model ZHANG Zhigang1, JIN Yongli1, WANG Dongyin1, FU Zhijun1, QIN Guodong2 China Mechanical Engineering    2025, 36 (03): 407-413.   DOI: 10.3969/j.issn.1004-132X.2025.03.004 Abstract （414）      PDF（pc） （4037KB）（89）       Knowledge map    Save  Based on dynamics model smoothing formulation of equivalent multi-link system, a tip-trajectory following algorithm was proposed for motion planning of hyper-redundant SARs in narrow and confined spaces. Regarding SAR as a multi-link system of joint points constrained to move on collision-free trajectory curve of tip, and the dynamics equation of rigid-flexible coupling system was derived using virtual work principle. The length conditions of robot arm segments were guaranteed by axial stiffness of connecting rods, and the influences of high-frequency components were filtered out from the model level by employing model denoising method, so that the conventional explicit algorithm might be used to calculate the solution of equation of equivalent multi-link system efficiently. The proposed algorithm may specify the velocity law of tip or base of snake-arms, and realize the motion planning of SAR along tip-trajectory. Due to the strictly limited joint points of SAR moving on feasible trajectory curve, obstacle avoidance motion planning may be achieved in narrow and deep cavity environments. After solving typical numerical examples in planar and spatial cases, the results show that the proposed algorithm has sufficient computational accuracy and efficiency for the motion planning of SARs. Reference | Related Articles | Metrics | Comments（0）

Select

Study on Low Wear Machining Method of High Volume Fraction SiCp/Al Composite Materials by ECM-mechanical Combined Machining Processes Method HE Bin, ZHOU Xingyu, LU Hongyu, ZHANG Junfei, DING Kai, LI Qilin, LEI Weining China Mechanical Engineering    2025, 36 (04): 753-759.   DOI: 10.3969/j.issn.1004-132X.2025.04.012 Abstract （411）      PDF（pc） （12862KB）（156）       Knowledge map    Save To improve the problems of tool wear, poor surface quality and low machining efficiency of aluminum-based silicon carbide（SiCp/Al) composites with high volume fraction under conventional machining, an ECM-mechanical combined machining method was proposed, and the ECM-mechanical combined machining experiments of 60% volume fraction SiCp/Al composites were carried out. The results show that SiC particles are exposed on the surfaces with the removal of aluminum matrix. There is a certain depth of transition zone between the surface of the workpiece and the matrix after ECM, the aluminum matrix in the transition zone is locally removed, and the binding force of SiC particles is reduced. When the diamond grinding rod is used for machining the transition zone, the aluminum matrix adhesion phenomenon is not observed, the diamond grinding rod has almost no wear, and the surface damages are obviously reduced. The machinability of high volume fraction SiCp/Al composites may be improved by ECM-mechanical machining processes. Reference | Related Articles | Metrics | Comments（0）

Select

Thread Extension Stress Analysis of Bolts under Pre-tensioning Conditions GUAN Jiaoyue1, GAO Yuan1, AI Yanting1, TIAN Jing1, YAO Yudong2 China Mechanical Engineering    2025, 36 (05): 923-932.   DOI: 10.3969/j.issn.1004-132X.2025.05.004 Abstract （410）      PDF（pc） （7649KB）（146）       Knowledge map    Save  It was difficult to accurately determine the thread stresses on the bolts under pre-tensionsing conditions， which might lead to strength fracture and premature loosening of the threads， and the reliability of the bolt joints was compromised. Currently， the contact state of the thread surfaces was usually described by stresses under an absolute coordinate system. However， the simulated stress direction was at an angle to the actual thread surface. The analysis results were not intuitive. Therefore， a thread mathematical model was derived and the extended stress analysis method of thread contact surfaces was proposed. Then， the finite element model of bolt joints was established for the structural characteristics of bolts. And the accuracy of the model was verified by tests. Finally， the extended stress analysis method was applied to study the thread surface stress and the distribution characteristics of bolts. The results show that the maximum error between the simulated preload and the testing preload is only 5.78%, where the accuracy of the simulation model is demonstrated. The extension stress analysis method may reflect the continuity and monotonicity of the stress distribution on the thread surfaces, and the method also reflects the optimal preload. The decreasing rate of the stress on the same layer thread is inversely proportional to the stress. From the stress analysis， the reason why the stresses on the thread are mainly concentrated in the first three turns is illustrated. The thread extension stress analysis method proposed herein is more intuitive and accurate. The paper may provide theoretical support for the anti-loosening analysis and reliability analysis of bolts. Reference | Related Articles | Metrics | Comments（0）