20 February 2024, Volume 60 Issue 4
    

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  • YAN Ruqiang, XU Wengang, WANG Zhiying, ZHU Qixiang, ZHOU Zheng, ZHAO Zhibin, SUN Chuang, WANG Shibin, CHEN Xuefeng, ZHANG Junhui, XU Bing
    Journal of Mechanical Engineering. 2024, 60(4): 3-31. https://doi.org/10.3901/JME.2024.04.003
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    As engine performance requirements continue to improve, the operating conditions of the fuel control system have become harsher and the boundary conditions have become more complex. There are various causes of fatal failures in fuel control systems,including inherent pressure pulsation of the fuel pump and fluid-solid coupling vibration of pipelines and valves, leakage caused by corrosion or aging of sealing rings, increased wear due to oil contamination or lubricating oil failure, etc. At the same time, the fuel control system has the characteristics of few measuring points, variable operating conditions, strong interference, and strong nonlinearity. Therefore, there is an urgent need for fault diagnosis technology in this field while facing huge challenges. In order to promote the development of fault diagnosis technology in the field of fuel control systems, this study reviews the main methods and classifications of fault diagnosis technology after summarizing the characteristics and common faults of the fuel control system.Furthermore, from the perspective of hydraulic component interchangeability, the current research status of key components of fuel control systems is summarized based on physical models, signal processing and artificial intelligence diagnostic methods. Finally, the challenges and opportunities existing in fuel control system fault diagnosis technology are pointed out.
  • ZHANG Junhui, LIU Shihao, XU Bing, HUANG Weidi, LÜ Fei, HUANG Xiaochen
    Journal of Mechanical Engineering. 2024, 60(4): 32-49. https://doi.org/10.3901/JME.2024.04.032
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    Axial piston pumps are the heart of the hydraulic system of aerospace, ocean ships, engineering machinery and other high-end equipment. They deliver transmission blood with stable pressure and flow to the hydraulic system. The reliability and safety of axial piston pumps have direct affects on the performance of the hydraulic system and even the complete machine. Therefore,utilizing intelligent technology to achieve predictive maintenance of axial piston pumps has been a research hotspot in recent years. At the same time, the development of unmanned and intelligent equipment has also emphasized the intelligent technology of axial piston pumps. To explore the development direction of the intelligent technology for axial piston pumps and provide a feasible path for the high-quality development, this study reviews the development history and research status of the intelligent technology of axial piston pumps from four aspects, namely, intelligent condition monitoring, intelligent fault diagnosis, intelligent life prediction and intelligent decision regulation. The existing problems and difficulties of the intelligent technologies for axial piston pumps are explored, the challenges of the existing intelligent technologies are summarized, and the future development trends are forecasted.
  • WANG Xingjian, YANG Xinyu, WANG Shaoping
    Journal of Mechanical Engineering. 2024, 60(4): 50-65. https://doi.org/10.3901/JME.2024.04.050
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    The large civil flight control system is critical for aircraft attitude adjustment and maintenance. During flight, control system faults can degrade aircraft control performance, and in severe cases, even lead to dispersion of the aircraft response, resulting in serious consequences. Deep research on the fault-tolerant control technology of the control system during flight is of great significance to improve flight control performance and guarantee system stable operation. From the perspective of control, the current fault-tolerant control methods for large civil flight control systems are summarized and summarized. Firstly, the composition of the flight control system is introduced and the main types of system faults are analyzed, including control surface faults, actuator faults,sensor faults, and process faults; Secondly, the technical progresses in fault-tolerant control of flight control system are discussed in depth, the advantages and disadvantages of various fault-tolerant control methods are compared and summarized; Thirdly, redundant resource allocation in the flight control system and its role in fault-tolerant control are described; Finally, the applications of flight control system fault-tolerant techniques in practical engineering are summarized, and the main challenges and opportunities currently facing the field of flight control system fault-tolerant control are outlined.
  • SHI Jian, LIU Dong, WANG Shaoping
    Journal of Mechanical Engineering. 2024, 60(4): 66-81. https://doi.org/10.3901/JME.2024.04.066
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    Digital twin technology and PHM technology are two hot research directions in the field of intelligent manufacturing. On the basis of summarizing and analyzing the current status of PHM technology, this study summarizes the key issues that currently restrict the development and application of PHM technology, including incomplete research on equipment failure mechanisms,incomplete data throughout the entire lifecycle, insufficient methods for monitoring health status, insufficient synthesis of multi-level status information, and uncertainty management issues. And it elaborates on the unique advantages of digital twin technology in solving these shortcomings, and proposes the construction of multi-dimensional digital twin models based on first principles, multi-dimensional data mapping in virtual and real spaces, efficient iterative correction of twin technology state consistency measurement and model, and system health assessment, prediction, and maintenance decision-making based on multi domain features as key technologies to construct the DT-PHM research architecture. With the continuous advancement and development of technology, the two technologies are constantly deeply integrated. The complex system health management technology based on digital twins will undoubtedly become one of the key technologies for future equipment full lifecycle maintenance and predictive maintenance.
  • WANG Songli, FANG Xudong, GAO Bonan, ZHAO Libo, TIAN Bian, LIN Qijing, ZHANG Zhongkai, RAO Hao, LI Yu, JIANG Zhuangde
    Journal of Mechanical Engineering. 2024, 60(4): 82-91. https://doi.org/10.3901/JME.2024.04.082
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    The amplitude stability and frequency tracking of the detection signal of the silicon micro resonant pressure sensor are very important to its performance, but the nonlinear characteristics of the current amplitude control and frequency tracking methods will cause nonlinear changes in the vibration frequency of the resonator, which limits comprehensive accuracy further improvement of the sensor. In order to reduce the influence of the nonlinear change of the resonator vibration frequency, based on the linearization analysis theory of automatic gain control(AGC), the AGC and phase compensation model is established for the high-Q silicon micro-resonant pressure sensor. With the model, the control characteristics of AGC amplitude control and frequency tracking linearization, and the effect of phase compensation on closed-loop control performance are analyzed. The self-excited drive based on AGC has been proved to make the resonator work stably at the resonant frequency and keep the amplitude stable. Simulink/PSpice simulation verifies the accuracy of the linearization analysis of the nonlinear system. Afterwards, a control circuit is designed and fabricated based on the AGC and phase compensation model for the silicon resonant pressure sensor, which can make the frequency stability of the whole meter better than ±0.05 Hz@sampling period 5 ms, and the comprehensive accuracy is better than ±0.02%. The engineering application of AGC in resonant pressure sensors solves the problem of sensor performance degradation caused by the nonlinear frequency tracking of resonators. The study in this work demonstrates AGC and phase compensation control can be widely used in closed-loop control of high-Q resonators.
  • TIAN Bian, LIU Jiangjiang, ZHANG Zhongkai, LIU Zhaojun, MA Rong, LIN Qijing, JIANG Zhuangde
    Journal of Mechanical Engineering. 2024, 60(4): 92-100. https://doi.org/10.3901/JME.2024.04.092
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    A new micro-electro-mechanical system(MEMS) thin-film temperature sensor is proposed for the intelligent sensing in hydraulic systems, which has a small size and high temperature measurement accuracy to realize the accurate sensing of fluid temperature signals. A new temperature measurement material system based on polymer-metal-ceramic materials is developed. At the same time, a multi-node three-dimensional array electrode structure is innovatively proposed. For the problem of deposition of thermoelectric thin films on three-dimensional curved polymer substrates, the graphical transfer of thin films on curved substrates is realized based on MEMS magnetron sputtering technology. The test results show that the prepared multi-node type thin film temperature sensor can achieve a sensitivity factor of 42 μV/℃ in the range of-60-200 ℃, a temperature time drift rate of 0.012 ℃/min, a repeatability error of 0.32%, a maximum hysteresis of 1.3% and a full scale error of less than 0.5% FS in the static test from-60-100 ℃. In the comprehensive performance test, the sensor still has a high temperature resolution under the impact of high-speed hot airflow, and can work normally for a long time in different working materials for more than 24 h, which can meet the demand of temperature measurement for a long time to maintain the sealability and stability in the actual hydraulic system.
  • DING Ruqi, XIONG Wenjie, CHENG Min, XU Bing
    Journal of Mechanical Engineering. 2024, 60(4): 101-112. https://doi.org/10.3901/JME.2024.04.101
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    The independent metering control system(IMCS) increases the system's intelligence level with electronic feedback and sophisticated control strategies. However, the higher safety risk prohibits the system from wide commercial application. Towards the machinery safety standard ISO 13849, the evaluation method of the safety performance for the IMCS is presented. To address the features including multi-control DOFS, multi-variable feedback, and multi-mode switching, a safety model covering the four operating quadrants is built by the fault-tree analysis and Boolean algebra. Then, the mapping from the fault-tree model to the predefined safety structure in ISO 13849 is established, such that the calculations of the system safety level PL and its PFHd are derived. Considering the normal controller, fault detection, and fault-tolerant control, the transformation of the safety structure from Cat.1 with the single channel to Cat.3 with dual channels is captured. The evaluation demonstrates that the PL of the IMCS only reaches the b level, which can not meet the requirements of the d level for the earth-moving machinery. By introducing fault detection,PL only increases to the c level. PL value of d or even the highest e level can be obtained by the fault-tolerant control. Complying with machine functional safety, the investigation contributes an evaluation and guidance for the control and fault diagnosis/tolerance design in the intelligent electro-hydraulic system.
  • ZHAO Xingyu, WANG Bo, QUAN Long, GE Lei, ZHOU Xingwei
    Journal of Mechanical Engineering. 2024, 60(4): 113-125. https://doi.org/10.3901/JME.2024.04.113
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    Existing multi way valves have problems such as difficulty in controlling large flow and low pressure losses, and poor dynamic characteristics. The inlet and outlet of the multi way valve are coupled, resulting in large pressure loss at the valve port and low system freedom. The existing multi way valve is difficult to meet the requirements of high-end hosts for maneuverability, energy conservation, intelligence, and load adaptability. Therefore, based on the advantages of high flow control characteristics of cartridge valves and good slide valve micromotion performance, a new configuration is innovatively proposed. This new configuration is to connect two flow amplification proportional cartridge valves in series at the inlet and outlet of the reversing spool valve, and further develop a series spool valve port independently controlled multi way valve. The two cartridge valves can be designed as flow control or pressure control functions based on control requirements. The valve has a high degree of freedom in the system and has a high potential for intellectualization. In order to achieve high-precision redundant control of flow and pressure, a series two-stage displacement closed-loop+parallel flow/pressure closed-loop control strategy is designed. The characteristics of the valve under three operating modes of position, flow, and pressure were studied through simulation. Further, a sample valve was trial-produced. A test rig was built to test the pressure loss characteristics, displacement hysteresis, flow control characteristics, dynamic response characteristics, and steady-state load characteristics. The results show that the rated flow rate of the sample valve reaches 300 L/min,and the displacement hysteresis of the main valve is <1%; Main valve step response <35 ms, with high dynamic characteristics;Maximum flow deviation <5%, high flow control accuracy.
  • ZHOU Ning, YAO Jianyong, DENG Wenxiang
    Journal of Mechanical Engineering. 2024, 60(4): 126-133. https://doi.org/10.3901/JME.2024.04.126
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    Proportional servo valves are widely applied in intelligent engineering machinery, national defence equipment and other high-end hydraulic systems. For the intelligent proportional servo valve, flow force is the most important factor limiting the improvement of its intelligent level. In order to solve the above problems, a flow force compensation neural network-based robust controller(FF-NNRC) of the valve centre is developed. Firstly, Fluent is employed to obtain the flow force information of proportional servo valve under different spool displacements and pressure boundary conditions, which can be used to simulate the flow force disturbance of practical working conditions. Neural network is designed to learn and approximate the flow force disturbance, then handles it in the feedforward model compensation term dynamically, robust term is formulated to deal with other disturbances and neural network estimation error. Lyapunov stability theory proves that the proposed control strategy can achieve the bounded stability of the system. Simulation results show that, compared with traditional PID controller and model compensation robust controller(MC-RC), the proposed controller has higher control accuracy and anti-interference ability.
  • WANG Bo, ZHAO Xingyu, QUAN Long, ZHAO Bin, LI Yunwei, HAO Yunxiao
    Journal of Mechanical Engineering. 2024, 60(4): 134-142. https://doi.org/10.3901/JME.2024.04.134
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    The flow-control method of pressure compensation is widely used and reliable. But limited by the mechanical structure,there are some shortcomings, such as low control accuracy, single control function, limited flow range and so on, which are difficult to meet the development of intelligent host equipment. Therefore, this study proposes a variable-gain flow-control principle based on active differential pressure regulation. A force control unit is added on the compensator to change the force balance state of the compensator spool, enabling active adjustment of the main valve pressure differential and achieving the purpose of changing gain to control flow. In the study, the principle of variable gain flow control with pressure difference regulation is theoretically analyzed, and a proportional electromagnetic direct drive scheme is given. Then a disturbance compensation strategy is designed to solve the technical problem of the compensator low control accuracy, and a nonlinear flow correction strategy is designed to set the valve flow characteristic curve customize. Finally, experiments are used to verify the feasibility of the proposed principle and designed control strategy. The experimental results show that by continuously controlling the output force of the proportional electromagnet, the differential pressure and flow of the main valve can be changed in proportion, and by changing the differential pressure in real time,the main valve can obtain different flow gains and flow ranges; compensating the flow force, the accuracy of flow control is improved,and the flow control deviation under steady-state load is reduced from 27% to about 4%; adopting the nonlinear flow correction strategy, the main valve flow curve can be set independently, and multiple throttle flow control effects based on the same throttle groove are realized.
  • GAO Qiang, LI Linfei, ZHU Yuchuan
    Journal of Mechanical Engineering. 2024, 60(4): 143-154. https://doi.org/10.3901/JME.2024.04.143
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    Aiming at the technical requirements for highly reliable electro-hydraulic pressure servo control of variable-speed helicopter friction clutch transmission system, an array digital valves-controlled electro-hydraulic pressure servo structure is proposed based on A-type half-bridge hydraulic resistance and parallel digital hydraulic technology. Firstly, based on an in-depth analysis of the working principle of the system, its mathematical model is established, and the output flow characteristics of the equal coded array digital valves are revealed. Then, to improve the pressure control accuracy and the service life of the digital valves, a hybrid coding control strategy that integrates nonlinear PNM(pulse number modulation) coding, asymmetric differential PWM(pulse width modulation), signal buffer allocation, and signal cyclic allocation technology is proposed. Experimental results show that when the hybrid coding control strategy is adopted, the maximum and average errors are reduced by 47.6% and 87.9% respectively compared to the PNM coding controller, and the standard deviation of switching times is reduced from 31.6 to 2.5 compared to the differential PWM controller. Therefore, the proposed hybrid coding control strategy can obtain a better balance between the pressure control accuracy and the uniformity of the switching times among the digital valves.
  • YAO Jing, YANG Shuai, YIN Hang, WANG Yunchang, WANG Wenjing, QIU Mingjun
    Journal of Mechanical Engineering. 2024, 60(4): 155-166. https://doi.org/10.3901/JME.2024.04.155
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    Under the current driving control method, the digital valve has the problems of slow dynamic response, small static linear controllable range, and high power. An intelligent driving method of the digital valve based on a soft measurement of the valve core displacement is proposed. The mechanism model of the digital valve is established, and the dynamic response process of the digital valve is analyzed. The driving voltage and valve inlet pressure are the key parameters affecting the response speed of the digital valve.The valve core displacement soft measurement model is established, and the influence of the correction temperature on the displacement soft measurement model is analyzed by finite element simulation and experimental analysis. The accuracy reaches 92.04 %. Based on the influence of key parameters on the dynamic response of the digital valve, an intelligent drive method is proposed. The soft sensor value of the valve core displacement is used as the condition of accurate switching in the multi-stage drive stage. In the maintenance stage, the driving signal is adjusted intelligently to adapt to the change of pressure. The experimental platform of the digital valve performance test is built to verify the effectiveness of the intelligent drive method. The results show that compared with the single voltage drive method, the intelligent drive method can reduce the opening and closing response time by 43.9%. The linear range of the duty cycle-flow characteristic curve is increased by 20%, the saturation range is less than 10%, and the power loss is reduced by 66%. It effectively improves the dynamic and static characteristics of the digital valve, reduces the power loss of coil.
  • WANG Zhiying, LI Tianfu, XU Wengang, SUN Chuang, ZHANG Junhui, XU Bing, YAN Ruqiang
    Journal of Mechanical Engineering. 2024, 60(4): 167-177. https://doi.org/10.3901/JME.2024.04.167
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    As an energy supply component of hydraulic system, the fault diagnosis of axial piston pump is of great significance.However, most existing methods rely on expert knowledge for feature extraction, and the robustness to noise is poor. To tackle the problem that complex working conditions bring noise interference to the collected diagnostic signals of axial piston pump, an end-to-end denoising mixed attention variational auto-encoder method is proposed to directly extract the fault characteristics submerged in the noise, to realize the fault diagnosis of axial piston pump under noisy environment. The proposed method employs convolution variational auto-encoder to extract fault features from multivariate signals including pressure and vibration.By introducing the mixed attention mechanism, hidden layer features of the encoder are weighted and fused, enhancing the fault features while weakening the noise. The adaptive soft-threshold denoising method is further applied to reducing the noise interference in extracted features, realizing the fault diagnosis of axial piston pump under strong noise. The effectiveness of the proposed method is verified by the fault implantation experiment and noise robustness experiment of an axial piston pump, and the results show 99.32% diagnosis accuracy under 5 dB noise and 69.72% under-5 dB noise, which outperforms commonly used diagnosis methods.
  • LIU Siyuan, AI Chao, YU Chunsong, ZHANG Weizhe, CHEN Wenting, KANG Wei
    Journal of Mechanical Engineering. 2024, 60(4): 178-188. https://doi.org/10.3901/JME.2024.04.178
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    The performance degradation state of the wear process of the slipper pair is affected by many aspects such as surface morphology and friction characteristics. It is inaccurate to extract any one of the characteristic parameters as indicators to evaluate its performance degradation state. In order to improve the evaluation accuracy, a multi-parameter intelligent fusion method based on deep belief network is proposed to evaluate the performance degradation state of the slipper pair. Fractal parameters such as fractal dimension, scale coefficient and characteristic roughness are extracted from the surface topography of slipper by fractal theory, and friction coefficient is used as the evaluation index of friction characteristics to construct the evaluation index system of performance degradation state. The gray correlation degree between the friction coefficient signal and the completely stationary Gaussian white noise sequence signal is calculated, and the degradation state is divided into regions according to the gray correlation degree. Deep belief network theory is applied to perform intelligent fusion and feature extraction of multiple index parameters, and a performance degradation state assessment model is established. The simulation test of slipper wear process is carried out to analyze the influence rule of index parameters and gray correlation degree on performance degradation state. The evaluation model is trained and tested through the constructed sample data set. The results show that the evaluation accuracy of the model for performance degradation state can reach more than 97%, which verifies the effectiveness and high accuracy of the method for performance degradation state evaluation of slipper pair.
  • WANG Dandan, HUANG Weidi, ZHANG Junhui, ZHAO Shoujun, YU Bin, LIU Shihao, LÜ Fei, SU Qi, XU Bing
    Journal of Mechanical Engineering. 2024, 60(4): 189-199. https://doi.org/10.3901/JME.2024.04.189
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    Wear state identification is of great significance to maintain the normal operation of axial piston pump. However, most existing fault diagnosis methods for axial piston pump are offline while those online are based on cloud computing, producing a long delay or a large amount of data, which cannot meet the real-time requirements of wear state identification. To cut down latency and data amount, a wear state identification method for axial piston pump based on edge computing is proposed. An edge node integrating the functions of data acquisition, data pre-processing, feature extraction and wear state classification is constructed to identify the wear state accurately and timely. Four kinds of wear states of axial piston pump are set as fault sources, and the corresponding wear fault dataset is established. To reduce the computational load of the edge node, the out-of-bag error of random forest is employed to select the sensitive features at the host computer. To classify the wear state, a feature-selected artificial neural network for wear state classification is trained at the host computer, and the data pre-processing and feature extraction algorithm together with model parameters are embedded into the edge node. The accuracy and real-time performance of the proposed method are demonstrated through comparisons with other methods and the online wear state identification experiment.
  • JIANG Xiangyu, FENG Yixiong, HONG Zhaoxi, HU Bingtao, SI Hengyuan, TAN Jianrong
    Journal of Mechanical Engineering. 2024, 60(4): 200-211. https://doi.org/10.3901/JME.2024.04.200
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    With the new-generation information technologies and artificial intelligence that are deeply integrated with the industry, the maintenance of industrial systems is moving from the manual regular maintenance to state-based intelligent maintenance(IM). Health status assessment(HSA) is a key link in IM. Systemic states are recognized via the monitored data whereby provide decision support for maintenance. Taking nuclear power plants(NPP) as the research object, an HSA framework is proposed based on multi-level integration of equipment, system, sub-function and function in a multi-department collaboration. Due to equipment groups with numerous state parameters, a weighted average fusion operator based on deviation weighting is proposed to fuse equipment-level parameters, which can timely highlight the abnormal equipment. Considering the different amount of data in different health states, an asymmetric multi-class learning method under imbalanced datasets is proposed to fuse the systems’ health values. The self-learning HSA model is established by the information transfer between multiple health levels, so that the health status of sub-functions can be self-perceived and assessed in a timely manner. The health assessors of multiple sub-functions are fused based on ensemble learning to obtain a macro-level operational function HSA decision. Exemplified with the reactivity function of the NPP, the proposed HAS frame is verified effective.
  • SHAO Haidong, LIN Jian, MIN Zhishan, MING Yuhang
    Journal of Mechanical Engineering. 2024, 60(4): 212-221. https://doi.org/10.3901/JME.2024.04.212
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    In practical engineering, it is difficult to acquire sufficient available fault samples of gearbox with the same distribution, in addition, the acquired unlabelled samples will inevitably be mixed with some out-of-distribution unknown interference samples, which will bring challenges to the existing research on intelligent fault diagnosis of gearbox. A new method based on an improved semi-supervised prototype network is proposed for cross-domain fault diagnosis of gearbox between different working conditions under out-of-distribution interference samples. First, a label allocation criterion is designed, which can fully exploit the information and assign pseudo-labels of the unlabelled samples to effectively suppress out-of-distribution interference samples. Then, a modified cost function is defined based on label smoothing and metric scaling to fully evaluate the similarity between fault samples, which can exploit the generic characteristics of the meta-learning task, and further improve network generalisation. The proposed method is used to analyse the experimental data of gearbox under different health states, and then different few-shot cross-domain diagnosis scenarios and out-of-distribution distribution samples are set up for comparison and verification. The experimental results show that the proposed method can more effectively achieve the cross-domain fault diagnosis of gearbox under different working conditions with few samples compared with the existing methods.
  • ZHAO Jiahao, HUANG Hanxiong
    Journal of Mechanical Engineering. 2024, 60(4): 222-229. https://doi.org/10.3901/JME.2024.04.222
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    A novel approach is proposed to rapidly prepare dual-level microstructured flexible pressure sensors with micro-papillae,which are applied in weak physiological signals detection. The flexible thermoplastic polyurethane sheets with the dual-level and single-level microdomes array and the flat surface are rapidly prepared by using compression molding. Then the gold-sprayed microstructured sheet and the graphite-coated flat sheet are assembled into flexible piezoresistive pressure sensors face-to-face. It is demonstrated that the dual-level microstructured pressure sensor(D-Sensor) with micro-papillae distributed on the surface of microdomes exhibits a higher sensitivity(0.061 kPa-1) and obviously higher linearity(with a linear correlation coefficient of upto 0.996) in linear low-pressure region(0~11 kPa) than the pressure sensor with the single-level microdomes array. This is attributed to the fact that the deformation of the dual-level microdomes under pressure obeys the Archard theory, and the area of the contact regions is increased largely with raising pressure. The D-Sensor has a short response time(100 ms) and maintains a stable piezoresistive response during 1000 cycles of cyclic compression/release tests(under 9 kPa pressure). The D-Sensor can accurately monitor some physiological signals corresponding to weakly mechanical stimulation, such as wrist pulse, pronunciation, and respiration. The results demonstrate that the dual-level microstructured sensors fabricated by the proposed rapid approach has high sensing performance and so can be applied in health detection field.
  • SONG Guorong, SONG Xiehong, LÜ Yan, LIU Bing, HE Cunfu, WU Bin
    Journal of Mechanical Engineering. 2024, 60(4): 230-238. https://doi.org/10.3901/JME.2024.04.230
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    Based on the non-contact ultrasonic testing method, the bonding quality of composite bonding structure is simulated and experimentally explored. Firstly, the time-domain simulation model of ultrasonic transmission characteristics of composite bonded structures is established, the frequency-domain transmission coefficient spectrum is extracted, and the effects of interface weakening and cohesion weakening on ultrasonic transmission characteristics of bonded structures are analyzed. At the same time, the spectrum of ultrasonic transmission coefficient in different bonding states is in good agreement with the calculation results of plane wave theory.In addition, fiber reinforced composite(FRP) bonding structures with different bonding interface states and adhesive layer cohesion weakening states were prepared. Based on the water immersion ultrasonic measurement system, the effects of different bonding interface states and cohesion weakening states on the ultrasonic transmission coefficient spectrum are experimentally investigated.The relationship between the ultrasonic transmission characteristics in the bonding structure and the bonding quality is analyzed,which is consistent with the simulation results. In addition, according to the mapping relationship between bonding quality and ultrasonic transmission characteristics in composite bonding structures, it also lays a solid foundation for nondestructive characterization and evaluation of composite bonding structures.
  • LI Ziqing, CUI Zhangcai, BIAN Subiao, LI Huihui, LU Jing, ORIOL Arteaga, XU Xipeng
    Journal of Mechanical Engineering. 2024, 60(4): 239-249. https://doi.org/10.3901/JME.2024.04.239
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    Aiming at the characteristics of ultra-thin(the experiment involves only a few nanometers) and transparent damage layer on the surface of single-crystal diamond substrate after ultra-precision machining, a method based on spectral ellipsometry is proposed to achievenon-destructive measurement and characterization of the thickness and refractive index of the damage layer. Firstly, a two-layer model of “roughness layer + pure substrate” is established, and the seed crystal substrate before processing is measured by discrete Mueller matrix ellipsometry mode, and its optical constants are obtained by analyzing the measurement data, which are used for the ellipsometric numerical inversion of the subsequent processing damage layer. This can prevent the coupling of ellipsometric parameters between the damage layer and the substrate. Secondly, according to the characteristics of the substrate after processing, a three-layer optical model of “roughness layer + damage layer + pure substrate” is established, and a multi-point fitting analysis strategy is used to achieve non-destructive characterization of the damage layer of diamond substrate in two typical machining stages of rough grinding and fine grinding is realized, and the difference in the damage layer between single-sided grinding and double-sided grinding is further explored. The results show that the refractive index of the seed sample is very close tothe theoretical value of the diamond, and their variation trends with wavelength are consistent with each other, which indicates the measurement mode and the substrate refractive index fitting strategy are feasible. The thickness and refractive index of the damage layer after rough grinding are higher than those after fine grinding. The refractive index of the damage layer after double-sided grinding and single-sided grinding is almost the same in the infrared band, but different in the ultraviolet-visible band. The ellipsometry results of damage layer thickness are compared with those observed by transmission electron microscope(TEM), which has verified the accuracy of ellipsometry characterization. The proposed method can non-destructively measure the thickness and refractive index of the ultra-thin damage layer of the single-crystal diamond substrate, and characterize the surface quality of the substrate after ultra-precision machining, which will contribute to the process optimization of ultra-precision machining of diamond substrates.
  • WANG Xiaoya, WANG Jian, QIN Peng, HAN Xingcheng, NIE Pengfei, HAN Yan
    Journal of Mechanical Engineering. 2024, 60(4): 250-258. https://doi.org/10.3901/JME.2024.04.250
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    A method is proposed to address the multimodal and dispersive nature of ultrasonic guided waves in practical detection scenarios, where mixed signals with various modes are present at the same excitation frequency, affecting the sensitivity of guided wave detection. Based on the mathematical modeling of guided wave dispersion signals, a single-mode ultrasonic guided wave extraction method is introduced using guided wave basis function projection transformation. Initially, mathematical models for each modal guided wave signal are established using the dispersion transfer function. These modal guided wave signals are then formulated into a set of guided wave mode bases. Subsequently, employing the mode basis functions as the projection transformation kernel, the received signals undergo a projection transformation, enabling the effective extraction of single-mode guided wave signals from the superimposed multimodal signals without the need for dispersion compensation. Simulation and experimental signal processing involving Lamb waves and mixed modes on a plate demonstrate the efficacy of the proposed method in achieving the extraction of single-mode guided wave signals without requiring additional dispersion compensation steps, thereby simplifying the ultrasonic guided wave detection process and enhancing sensitivity to guided wave signals.
  • ZHANG Yue, LU Yan, PENG Ruitao, ZHU Linwei, LEI Bei, JIANG Jiachuan
    Journal of Mechanical Engineering. 2024, 60(4): 259-283. https://doi.org/10.3901/JME.2024.04.259
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    With the low-carbon transformation of global industrial automobiles, the challenges faced by related connection technologies in the process of body lightweight are increasing. Considering the cost and effect of lightweight, selecting body materials reasonably, matching different connection processes, and providing more ideas for product design stage under the premise of meeting industry quality standards and reducing product weight have become an inevitable trend of lightweight technology development. The rational use of various lightweight materials can effectively reduce the weight of the body and improve the performance of the body.The research progress of several new connection processes for different lightweight materials of the body is systematically summarized. The metallurgical connection technology, mechanical connection technology, bonding technology and composite connection technology are reviewed and analyzed. The research progress of various new processes and their extended processes in recent years is described. The technical principles, connection strength criteria, process advantages, limitations and application status of various processes are analyzed in order to provide useful reference for the design and manufacture of new connection processes for automotive lightweight materials. Protect the body lightweight connection process.
  • WU Jizhan, WEI Peitang, LIU Huaiju, WU Shaojie, ZHU Caichao
    Journal of Mechanical Engineering. 2024, 60(4): 284-295. https://doi.org/10.3901/JME.2024.04.284
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    Gear rolling contact fatigue is an important bottleneck restricting the reliability, long life, and lightweight requirements of high-end equipment such as aviation, aerospace, new energy vehicles, and ships. Fatigue-resistant manufacturing is key to achieving high surface integrity and service performance. Revealing the relationship between high surface integrity, service life and fatigue limit has become a research focus in engineering and academia. The effects of conventional shot peening, dual shot peening, fine particle peening, barrel finishing, barrel finishing after shot peening, etc. on surface integrity and rolling contact fatigue properties of AISI 9310 carburized and quenched aviation gear steel are discussed. Active design method for contact fatigue resistance is proposed accordingly. This work is the second part of this series of studies, which aims to reveal the relationship between surface integrity and service performance by carrying out rolling contact fatigue tests with different manufacturing processes. The results show that under the contact stress state of 2 500 MPa, compared with the grinding state, the contact fatigue life could be increased by 75.7%, 62.3%and 117% respectively by the dual shot peening, fine particle peening and barrel finishing. The rolling fatigue limit of samples treated by shot peening and shot peening-barrel finishing could reach 2 269 MPa and 2 553 MPa, respectively, which is 2.9% and 14.87%higher than that of the carburized grinding state.
  • WANG Xingxing, WU Gang, HE Peng, YANG Xiaohong
    Journal of Mechanical Engineering. 2024, 60(4): 296-304. https://doi.org/10.3901/JME.2024.04.296
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    Ni/WC composite coating has been widely used in agricultural machinery, mould processing and new energy resources fields for its high hardness, high wear resistance and low friction coefficient. The first-principles calculation is used to study the Ni(111)/WC(0001) interface and Ni(111)/W2C(0001) interface behavior in Ni/WC composite brazed coating of construction machinery. The influence of W2C on the wear resistance of WC-reinforced Ni matrix composite brazed coatings is discussed. The calculation results reveal that the 5 atom-layers Ni(111) surface, 9 atom-layers WC(0001) surface and 9 atom-layers W2C(0001)surface are selected to represent the block characteristics. Among the six stacking sequences, the highest Wad(adhesion work) is 7.42J/m2 at B site from C-terminated structure of Ni(111)/WC(0001) interface, then the interface bonding strength is the highest. The systematic analysis of the electronic structures at different interfaces shows that Ni atoms are more likely to bond with C atoms, the properties of bonds between Ni and C atoms are mainly ionic bonding, and the properties of metallic bonding between Ni atoms at the interface are much weaker than non-interface Ni atoms.W2C phase should be strictly controlled at the coating interface. The theoretical basis is provided for the manufacture of high wear resistance, high hardness and high strength composite coatings.
  • ZHANG Tingting, XU Zhenbo, WANG Yan, BIAN Gongbo, WANG Tao, WANG Wenxian
    Journal of Mechanical Engineering. 2024, 60(4): 305-315. https://doi.org/10.3901/JME.2024.04.305
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    In order to solve the problems that poor coordinated deformation of the dissimilar composite metal with large rolling reduction, difficulty in removing the interfacial oxide film and controlling the formation of intermetallic compounds(IMCs) in the fabrication process of Magnesium/Aluminum alloy composite plate by traditional hot rolling, a new method of rolling-welding process assisted by high-frequency pulse current is proposed for preparing magnesium/aluminum alloy composite plates. The interfacial morphologies and bonding strength of the composite plate are investigated under pulse current of 30 kHz, 400 A and 50%duty cycle that was loaded for 120 s with the different rolling reduction parameters. The results show that the shear strength of composite plate is the highest and up to 27.87 MPa when the rolling reduction is 16.8%. In addition, different degrees of molten liquid metals are extruded at the bonding interface in various rolling reduction. The IMCs transition layer is thick and reaches to 7.8 μm, and the interfacial morphology presents an obvious “toothed” structure when the rolling reduction is low(the rolling reductions are 16.8%and 22.3%). Accompanied by increasing of the rolling reduction, the thinner IMCs layers are reserved at the interface and also a flat interface is obtained. Comprehensive analysis shows that the Magnesium/Aluminum alloy composite plates can be fabricated by a low rolling reduction with the assistance of high-frequency pulse current, and the interfacial bonding mechanism can be summarized as follows: the metallurgical bonding mechanism of local high temperature at the bonding interface of Magnesium/Aluminum leads to part of base metal molten brazing and mutual atomic diffusion bonding. This can be contributed to the local high temperature of the bonding interface and exceeds the eutectic phase of the Mg-Al phase diagram above the eutectic point. On the one hand, the local temperature rise is due to an increase in contact resistance at the bonding interface. On the other hand, localized high temperatures are caused by skin-setting effects the skin and adjacent effects of high-frequency pulse current.
  • ZHOU Tian, CAI Lixun, HAN Guangzhao
    Journal of Mechanical Engineering. 2024, 60(4): 316-325. https://doi.org/10.3901/JME.2024.04.316
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    For homogeneous, isotropic and power-law hardening discs under normally loading at its center by a small punch with a flat indenter, based on the energy density equivalence, a novel elastic-plastic model to describe the relationship between the disc dimensions, power-law parameters, load and displacement is proposed, and a flat small punch test(F-SPT) method for obtaining the stress-strain curves and mechanical properties of the materials is developed. Numerical verifications are carried out using 48 kinds of materials with various combinations of elastic modulus, yield strength, and hardening exponent, and F-SPT are conducted for ten metallic materials. The results show that the stress-strain curves obtained by this method are consistent with those preset in finite element analysis and those obtained by uniaxial tensile tests. In addition, the elastic modulus, yield strength and tensile strength obtained by the novel method are in agreement with the uniaxial tensile test results.
  • CUI Guihan, YANG Chunli
    Journal of Mechanical Engineering. 2024, 60(4): 326-334. https://doi.org/10.3901/JME.2024.04.326
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    The 10Ni5CrMoV steel plate is welded with pulsed GMAW process using new high strength and high toughness steel welding wire, and the microstructure, mechanical property, strengthening and toughening mechanism of weld metals are analyzed.The results showed that the microstructure of weld metals are lath bainite, granular bainite, acicular ferrite and fine grain ferrite. The high-density dislocations in bainite improved the strength of weld metals. A small amount of M-A constituent in the weld metal is dispersed on the ferrite matrix and hindered the crack propagation, which improves the strength and toughness of the weld metal to a certain extent, but its strengthening effect is limited. A small amount of nonmetallic inclusion in weld metals could refine grains and promote the formation of acicular ferrite, which could improve the strength and toughness of weld metals and not damage the toughness. The yield strength of weld metals is 793 MPa, the elongation is 17.2%, the KV2 impact energy at-50 ℃ is 132 J, good mechanical property weld metals are obtained.
  • HU Long, LIU Hongyan, CHENG Huimei, CHEN Weiqi, FENG Guangjie, YE Yanhong, DENG Dean
    Journal of Mechanical Engineering. 2024, 60(4): 335-344. https://doi.org/10.3901/JME.2024.04.335
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    Based on SYSWELD software,a “thermo-metallurgical-mechanical” coupling computational approach with consideration of solid-state phase transformation is established to simulate temperature field, fraction of phase and welding residual stress in a multi-layer and multi-pass butt-welded joint of wear-resistant NM500 steel. Meanwhile, microstructure, hardness and surface residual stress distribution of the joint were observed by optical microscope, measured by micro-hardness tester and by hole-drilling method,respectively, and the measured data are compared with the corresponding simulation results. The results show that the simulated melting zone above the melting point of the NM500 steel butt-welded joint is in a good agreement with the actual melting zone, and this proves that the numerical simulation method reproduced the actual welding heat input for the butt-welded joint. For NM500 steel butt-welded joint, the peak value of longitudinal residual stress located the base metal adjacent to the heat-affected zone, and its value is about 1 600 MPa, which is similar to the yield strength of base metal at room temperature. The transverse residual stress distributed in the thickness direction in the shape of “tension-compression – tension”. In general, the magnitude and distribution of longitudinal and transverse residual stresses obtained by numerical simulation are in good agreement with the experimental measurements, which verified the effectiveness of the “thermo-metallurgical-mechanical” coupling computational method. Based on the numerical simulation results, the formation mechanism of welding residual stress in NM500 steel multi-layer multi-pass butt-welded joint is also investigated.
  • MA Yixing, YANG Yutao, GUAN Xiaohu, YANG Qi, ZHAO Tongxin
    Journal of Mechanical Engineering. 2024, 60(4): 345-356. https://doi.org/10.3901/JME.2024.04.345
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    The reliability of interfacial bonding has a significant impact on the mechanical properties of a laminated composite plate.A three-layered composite plate with the surface layers of twinning-induced plasticity(TWIP) steel and the central layer of interstitial free(IF) steel is fabricated by hot-roll-bonding and annealing processes. Through tensile-shear tests, microhardness measurements,quantitative analysis of alloying elements distributing around the bonding interface, and microstructure characterization before and after deformation, the formation of the bonding interface, the reliability of the interfacial bonding, and the inter-layer shear deformation behavior of the composite plate are investigated. The results are as follows. The bonding interface of the composite plate is essentially a thin-layered region with an average width of approximately 12 μm, which mainly contains lamellar martensite structure and has significantly higher hardness than the neighboring TWIP and IF steels. Around the thin interfacial layer, the main alloying elements C and Mn undergo redistribution. A mechanism is then proposed for the formation of the thin interfacial bonding region, based on the above characterizations and analyses. The inter-layer shear strength of the composite plate is higher than the shear strength of the IF steel, and the failure of the tensile-shear specimen takes place in the IF steel matrix, indicating that the interfacial bonding region develops a robust metallurgical bond with both the IF steel and the TWIP steel. During the tensile-shear deformation, the good plasticity of the IF steel contributes to inhibiting the initiation and propagation of parallel microcracks on both sides of the interfacial bonding region and perpendicular microcracks within the interfacial bonding region.
  • LIU Song, LI Junhui, LIU Yunfei, JI Jiang, XIE Weiwei, DOU Feng, LIU Jianglin, LIU Yu
    Journal of Mechanical Engineering. 2024, 60(4): 357-368. https://doi.org/10.3901/JME.2024.04.357
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    Special alloy strip with ultra-thin thickness has been widely used in many industries of national economy. Based on analysis of material characteristics and boundary conditions, traditional way of increasing rolling force to obtain thinner strip is broke through. Rolling process and program control requirements for special alloy strip with ultra-thin thickness are improved and also corresponding special rolling equipment is developed. Tension weighted rolling process which includes high-precision cascade dynamical system and its micro-tension control algorithm is innovated, so contradiction between large tension output and small tension fluctuation as well as technological requirements of small tension fluctuation in unsteady rolling stage are solved. Rolling model suitable for special alloy strip with ultra-thin thickness is established, including minimum rolling thickness model, automatic thickness control system and automatic profile control, which provides theoretical basis for breaking through minimum rolling thickness and realizing efficient precision rolling. And also technical equipment suitable for this rolling process is established. In particular, high tension coiler and its cone-sleeve adaptive support are developed,and corresponding equipment has the characteristics of high rigidity and good stability. Due to research of rolling process and technical equipment, the limit of minimum rolling thickness of strip is broken through, and stable tension weighted rolling process of 3 series stainless steel strip with thickness of 0.01 mm is developed,also quantitative relationship between tensile stress, rolling force and strip thickness is researched. Tensile stress is the key factor to break through the minimum rolling thickness of special alloy strip with ultra-thin thickness, and amplitude of tension fluctuation plays a decisive role in the stable rolling of this kind of strip.
  • GAO Qiang, WANG Jian, ZHANG Yan, ZHENG Xuyang, LÜ Hao, YIN Guodong
    Journal of Mechanical Engineering. 2024, 60(4): 369-390. https://doi.org/10.3901/JME.2024.04.369
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    As an advanced structural optimization approach, the essence of topology optimization is to obtain the structural topology configurations with the best performance by seeking the optimal distribution of materials in the design domain under given load and boundary conditions. In recent years, with the continuous development of optimization algorithms and computer science, structural optimization technology has a wide application prospect in aerospace, automobile, ship and other transportation engineering. Based on the theoretical research level, topology optimization approaches and characteristics of discrete and continuous structures are discussed.Then by considering the specific applications of topology optimization in aerospace, automobile, ship and other transportation engineering, the shortcomings of structural topology optimization and the challenges faced by their popularization are pointed out. At the same time, the present situation and development trend of topology optimization industrial software development and application from home and abroad are discussed. At present, the main problem faced by topology optimization is that in the iterative process of large-scale transportation engineering structure optimization, multiple finite element analysis is required which increases the complexity of calculation space and time. By considering the situation, the new discipline direction represented by isogeometric analysis and machine learning to improve the deficiency of topology optimization design is introduced, so as to shorten the design cycle of transportation equipment. and A preliminary discussion on the research trend in the future is also given.
  • DAI Guohong, ZHANG Daohan, PENG Simin, MIAO Yifan, ZHUO Yue, YANG Ruixin, YU Quanqing
    Journal of Mechanical Engineering. 2024, 60(4): 391-408. https://doi.org/10.3901/JME.2024.04.391
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    The development and application of advanced electric vehicles has become the key technology to achieve “decarbonization”. Accurate state of health(SOH) prediction of battery can effectively characterize its operation performance. It is of great significance to the maintenance and life management of battery in electric vehicle. In recent years, a new generation of artificial intelligence technology represented by deep learning, reinforcement learning and big data technology has become a research hotspot in the application of battery state prediction. The basic theory of artificial intelligence technology and SOH and SOH influence factors is briefly introduced. Several main artificial intelligence algorithms in SOH prediction are summarized and discussed from the perspective of battery cell and battery system respectively. Finally, combined with emerging technologies such as big data, cloud computing and regional chain, some battery SOH prediction problems are discussed, which provides some ideas for breaking through the bottleneck of current power battery full life cycle management technology.
  • ZHU Haiyan, LI Jie, XIAO Qian, CHEN Daoyun
    Journal of Mechanical Engineering. 2024, 60(4): 409-419. https://doi.org/10.3901/JME.2024.04.409
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    A high-speed train brake disc dynamics model and a three-dimensional transient thermal mechanical finite element interaction model are developed to investigate dynamic effect of wheel vibration on the fatigue of the thermal-mechanical couplings of brake discs mounted on high-speed rails. The results show that the vibration acceleration value of the brake disc of high-speed train is the maximum in vertical direction and the minimum in transverse direction, and the vibration form is mainly brake jitter, and the jitter is the most severe in the range of 0-100 Hz; In comparison, the surface temperature of the brake disc attached to the shaft increases rapidly with the rail and decreases rapidly with temperature; The surface of the brake disc usually shows three hot circles;And the surface of the brake disc is located in the middle of the friction circle, the temperature is higher than the temperature on both sides, the temperature shows the gradient distribution of the three different friction differences. Brake disc surface fatigue damage and fatigue life distribution cloud diagram with and without wheel track tension basically corresponds to the distribution of the brake disc surface temperature field, the higher the thermal stress, the more serious the fatigue damage increase. The fatigue life of the brake disc surface is shortened.
  • ZONG Huaizhi, AI Jikun, ZHANG Junhui, JIANG Lei, TAN Shujie, LIU Yuxian, SU Qi, XU Bing
    Journal of Mechanical Engineering. 2024, 60(4): 420-429. https://doi.org/10.3901/JME.2024.04.420
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    Hydraulic actuated quadruped robots have bright application prospects and significant research values in unmanned area investigation, disaster rescue, material transport and other scenarios, due to their discrete landing positions and large payloads. As the most critical movement unit of a quadruped robot, the mass distribution of limb leg unit directly affects the dynamic performance of the robot, calling for a compact and lightweight design. This study focuses on the problem of excessive redundant weight in the thigh structure of the limb leg unit of Spurlos Ⅱ robot. The solid isotropic material with penalization algorithm is adopted to the thigh structure topology optimization, and the optimized mesh model is reconstructed using a method based on B-spline fitting approach for two-dimensional cross-sectional profiles. Then, to solve the problem of local stress concentration caused by model reconstruction, lattice filling structures are introduced to achieve further optimization. After optimization, the weight of the thigh structure component reduces by 36.01% to 1007.19 g, and its maximum equivalent stress decreases by 1.41%. Finally, the optimized leg limb unit demonstrated better dynamic performance in trajectory tracking experiments with different frequencies, proving the effectiveness of the proposed lightweight design method.
  • LI Ying, ZHANG Jiafang, ZHANG Zhaoyong, WANG Xincheng, ZHANG Jin, KONG Xiangdong
    Journal of Mechanical Engineering. 2024, 60(4): 430-437. https://doi.org/10.3901/JME.2024.04.430
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    In order to solve the problem of the swashplate axial piston pump causing the plunger neck fracture under high speed and high pressure, the design and verification of the plunger neck of the plunger pump are studied, and the design method of the minimum diameter of the plunger neck is proposed. Based on the force analysis of the plunger shoe assembly in the drain area, a force model of the plunger neck under high pressure is established. Based on the stress-strength interference distribution theory, combined with the stress distribution of the plunger neck and the fatigue strength of the plunger, the expression of the fatigue reliability of the plunger neck is proposed, and the minimum diameter of the neck of the plunger of the axial piston pump is obtained. The finite element method was used to perform static simulation analysis of the plunger with the minimum neck diameter, and the safety check of the plunger strength was realized by combining the stress cloud diagram. Under the rated working conditions, the axial piston pump designed according to the design method of the minimum diameter of the plunger neck was tested with volumetric efficiency and mechanical efficiency, the design criteria are used to verify the design of the plunger neck of the axial piston pump of similar products,and the rationality of the proposed design method of the minimum diameter of the plunger neck was verified.
  • SU Jiantao, DONG Shaohua, ZHU Shimin
    Journal of Mechanical Engineering. 2024, 60(4): 438-448. https://doi.org/10.3901/JME.2024.04.438
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    In the process of digital transformation, How to solve production scheduling problem,Researchers very attention. Machine failure is mixed flow shop to happen problem in production scheduling. Therefore,it is necessary to find a way to quickly solve the rescheduling of faulty machines. To this end, several main factors are needed to be considered, which are processing time the logistics loading and unloading time and the limitation of the layout of production equipment. Based on these considerations, a rescheduling method combining multiple rescheduling is proposed. Firstly, a dual-objective mathematical model is established, with the NSGA-II algorithm implanted into the system to solve the initial scheduling scheme. The algorithm uses heuristic rules and randomization to generate the initial solution and uses the simulation method to evaluate the scheduling scheme. Secondly, a variety of rescheduling methods are integrated, and the rescheduling method verified by equipment failure simulation and experimental verification heuristic rules can be used as part of the initial solution, which can greatly improve the search efficiency of the algorithm. The rescheduling method studied can effectively deal with machine failures in hybrid flow workshops and is of great significance.
  • PAN Xin, ZHANG Xin, LU Jiaqiao, WU Haiqi
    Journal of Mechanical Engineering. 2024, 60(4): 449-457. https://doi.org/10.3901/JME.2024.04.449
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    The rotor unbalanced self-recovery actuator is an effective solution to suppress the unbalance vibration of the rotor system of rotating machinery in real-time because it can adjust the mass distribution inside the device in real-time and compensate the unbalance vector inside the rotor system by moving the synthetic vector generated by the counterweight. A self-recovery rotor imbalance actuator based on ultrasonic motor accurate and stable regulation is introduced for the vibration faults caused by mass imbalance in the coaxial cantilever dual rotor system, and the structural composition and basic working principle of the device are described in detail. Based on the structural characteristics of the coaxial cantilevered dual-rotor system, a finite element model of the dual-rotor-actuator system is established, and quantitative analysis of the dynamics characteristics is carried out, which the impact of the actuator designed for the system structure on the critical speed of the original rotor system is within 3%. The results show that the self-recovery rotor unbalance actuator can reduce the rotor unbalance vibration by 53% in 3.2 s, which verifies the feasibility and effectiveness of the principle of the actuator.
  • TANG Hongtao, WEI Shupeng, LI Xixing, LEI Deming, WANG Kaipu
    Journal of Mechanical Engineering. 2024, 60(4): 458-472. https://doi.org/10.3901/JME.2024.04.458
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    Aiming at the problems of low level, low efficiency and high cost of the vehicle logistics in manufacturing enterprises, a mathematical model for collaborative optimization vehicle allocation and route is established. The model considers a variety of factors,including heterogeneous vehicles, cargo types, vehicle queuing and vehicle quantity. In addition, the logistics completion time,vehicle mileage and logistics cost are employed as the objectives of the model. To solve the model effectively, a hybrid discrete sparrow search algorithm is proposed. In the algorithm, an initialization method based on reverse learning is used to improve the diversity of the population, several discretization strategies are designed to accommodate the discrete characteristics of the problem.Moreover, a variety of local search strategies are designed to improve the search ability, and a solution retention strategy is designed to avoid the algorithm falling into local optimization. By analyzing an actual case of a cement enterprise, the effectiveness of the proposed strategies and the superiority of the proposed algorithm are verified. The obtained logistics scheme can effectively reduce the logistics cost by 11%, improve the logistics efficiency by 19.8%, and reduce the vehicle mileage by 29.1%.