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Prof. Dr. Liqing Chen
College of Engineering, Anhui Agricultural University

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Research Keywords & Expertise

0 Optimization
0 control
0 transmission system
0 Agricultural Robotics
0 Fluid-structure Coupling

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Short Biography

Liqing Chen, professor, doctoral supervisor, doctor of engineering, director of the Chinese Society of Agricultural Engineering, deputy director of the Farming Branch of the Chinese Society of Agricultural Machinery. In the past five years, he has presided over five national projects, 15 provincial and ministerial projects, published 11 SCI papers, and obtained more than 20 national patents.

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Journal article
Published: 18 June 2021 in Actuators
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This research focuses on four-wheel-drive electric vehicles. On the basis of the hierarchical coordinated control strategy, the coordinated control system of driving force distribution regulation and differential braking regulation was designed to increase the electric vehicles steering stability under special road working conditions. A seven-degree-of-freedom model of an electric vehicle was established in MATLAB/Simulink, and then a hierarchical coordination control model of the Electronic stability program and dynamic torque distribution control system was established. Adaptive fuzzy control was applied to ESP and, based on the neural network PID control, a torque distribution control system was designed. On the basis of the proposed coordinated control model, a performance simulation and a hardware-in-the-loop test of the control system under the typical working condition of single line shift were carried out. From the final results, it can be seen that the proposed control strategy can greatly improve the safety of the vehicle after serious side slip, increase the stability of the whole vehicle, and effectively increase the vehicle lateral stability.

ACS Style

Liqing Chen; Zhiqiang Li; Juanjuan Yang; Yu Song. Lateral Stability Control of Four-Wheel-Drive Electric Vehicle Based on Coordinated Control of Torque Distribution and ESP Differential Braking. Actuators 2021, 10, 135 .

AMA Style

Liqing Chen, Zhiqiang Li, Juanjuan Yang, Yu Song. Lateral Stability Control of Four-Wheel-Drive Electric Vehicle Based on Coordinated Control of Torque Distribution and ESP Differential Braking. Actuators. 2021; 10 (6):135.

Chicago/Turabian Style

Liqing Chen; Zhiqiang Li; Juanjuan Yang; Yu Song. 2021. "Lateral Stability Control of Four-Wheel-Drive Electric Vehicle Based on Coordinated Control of Torque Distribution and ESP Differential Braking." Actuators 10, no. 6: 135.

Journal article
Published: 11 June 2021 in Remote Sensing
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The aboveground fresh weight of weeds is an important indicator that reflects their biomass and physiological activity and directly affects the criteria for determining the amount of herbicides to apply. In precision agriculture, the development of models that can accurately locate weeds and predict their fresh weight can provide visual support for accurate, variable herbicide application in real time. In this work, we develop a two-stream dense feature fusion convolutional network model based on RGB-D data for the real-time prediction of the fresh weight of weeds. A data collection method is developed for the compilation and production of RGB-D data sets. The acquired images undergo data enhancement, and a depth transformation data enhancement method suitable for depth data is proposed. The main idea behind the approach in this study is to use the YOLO-V4 model to locate weeds and use the two-stream dense feature fusion network to predict their aboveground fresh weight. In the two-stream dense feature fusion network, DenseNet and NiN methods are used to construct a Dense-NiN-Block structure for deep feature extraction and fusion. The Dense-NiN-Block module was embedded in five convolutional neural networks for comparison, and the best results were achieved with DenseNet201. The test results show that the predictive ability of the convolutional network using RGB-D as the input is better than that of the network using RGB as the input without the Dense-NiN-Block module. The mAP of the proposed network is 75.34% (IoU value of 0.5), the IoU is 86.36%, the detection speed of the fastest model with a RTX2080Ti NVIDIA graphics card is 17.8 fps, and the average relative error is approximately 4%. The model proposed in this paper can provide visual technical support for precise, variable herbicide application. The model can also provide a reference method for the non-destructive prediction of crop fresh weight in the field and can contribute to crop breeding and genetic improvement.

ACS Style

Longzhe Quan; Hengda Li; Hailong Li; Wei Jiang; Zhaoxia Lou; Liqing Chen. Two-Stream Dense Feature Fusion Network Based on RGB-D Data for the Real-Time Prediction of Weed Aboveground Fresh Weight in a Field Environment. Remote Sensing 2021, 13, 2288 .

AMA Style

Longzhe Quan, Hengda Li, Hailong Li, Wei Jiang, Zhaoxia Lou, Liqing Chen. Two-Stream Dense Feature Fusion Network Based on RGB-D Data for the Real-Time Prediction of Weed Aboveground Fresh Weight in a Field Environment. Remote Sensing. 2021; 13 (12):2288.

Chicago/Turabian Style

Longzhe Quan; Hengda Li; Hailong Li; Wei Jiang; Zhaoxia Lou; Liqing Chen. 2021. "Two-Stream Dense Feature Fusion Network Based on RGB-D Data for the Real-Time Prediction of Weed Aboveground Fresh Weight in a Field Environment." Remote Sensing 13, no. 12: 2288.

Article
Published: 13 May 2021 in Acta Metallurgica Sinica (English Letters)
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The present article aims at elucidating the effect of thermo-mechanical controlled processing (TMCP), especially the finish cooling temperature, on microstructure and mechanical properties of high strength low alloy steels for developing superior low temperature toughness construction steel. The microstructural features were characterized by scanning electron microscope equipped with electron backscatter diffraction, and the mechanical behaviors in terms of tensile properties and impact toughness were analyzed in correlation with microstructural evolution. The results showed that the lower finish cooling temperature could lead to a considerable increase in impact toughness for this steel. A mixed microstructure was obtained by TMCP at lower finish cooling temperature, which contained much fine lath-like bainite with dot-shaped M/A constituent and less granular bainite and bainite ferrite. In this case, this steel possesses yield and ultimate tensile strengths of ~ 885 MPa and 1089 MPa, respectively, and a total elongation of ~ 15.3%, while it has a lower yield ratio of ~ 0.81. The superior impact toughness of ~ 89 J at −20 °C was obtained, and this was resulted from the multi-phase microstructure including grain refinement, preferred grain boundaries misorientation, fine lath-like bainite with dot-shaped M/A constituent.

ACS Style

Wen-Ting Zhu; Jun-Jun Cui; Zhen-Ye Chen; Yang Zhao; Li-Qing Chen. Correlation of Microstructure Feature with Impact Fracture Behavior in a TMCP Processed High Strength Low Alloy Construction Steel. Acta Metallurgica Sinica (English Letters) 2021, 1 -10.

AMA Style

Wen-Ting Zhu, Jun-Jun Cui, Zhen-Ye Chen, Yang Zhao, Li-Qing Chen. Correlation of Microstructure Feature with Impact Fracture Behavior in a TMCP Processed High Strength Low Alloy Construction Steel. Acta Metallurgica Sinica (English Letters). 2021; ():1-10.

Chicago/Turabian Style

Wen-Ting Zhu; Jun-Jun Cui; Zhen-Ye Chen; Yang Zhao; Li-Qing Chen. 2021. "Correlation of Microstructure Feature with Impact Fracture Behavior in a TMCP Processed High Strength Low Alloy Construction Steel." Acta Metallurgica Sinica (English Letters) , no. : 1-10.

Journal article
Published: 11 February 2021 in International Journal of Thermal Sciences
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Lubricant filling into a closed fluid domain of a transmission component has always been a challenge, for it is limited by a number of factors, like structural characteristics of a transmission component, load characteristics, and oil temperature of during an operation. This paper proposes a lubricant volume optimization model that takes into account the effect of temperature and heat, with an electronically controlled limited slip differential (ELSD) for an automobile taken as the study object. In the paper, an ELSD simulation model was firstly constructed, based on a CFD numerical simulation method. After model simplification and assumption, the probes were established for fluid speed and temperature parameters during gear rotation. The influence law of lubricant volume in the ELSD on convective heat transfer was then determined by analyzing the working conditions, including different rotational speeds and different oil immersion depths. Finally, the optimization model was constructed, with the numerical values after the steady-state temperature fluctuation and the time required for the fluctuation taken as evaluation indexes. In the study, by taking specific parameters for examples and based on the proposed optimization model, quadratic response surface method was used for equation fitting of multiple results obtained from the simulation, and the lubricant volume of 37.21% of the total volume was found to be optimal, which verified the feasibility of the model. The method provides a new approach for determining the lubricant volume for a transmission component.

ACS Style

Zhen Zhang; Xihai Jia; Tao Yang; Yili Gu; Weiwei Wang; Liqing Chen. Multi-objective optimization of lubricant volume in an ELSD considering thermal effects. International Journal of Thermal Sciences 2021, 164, 106884 .

AMA Style

Zhen Zhang, Xihai Jia, Tao Yang, Yili Gu, Weiwei Wang, Liqing Chen. Multi-objective optimization of lubricant volume in an ELSD considering thermal effects. International Journal of Thermal Sciences. 2021; 164 ():106884.

Chicago/Turabian Style

Zhen Zhang; Xihai Jia; Tao Yang; Yili Gu; Weiwei Wang; Liqing Chen. 2021. "Multi-objective optimization of lubricant volume in an ELSD considering thermal effects." International Journal of Thermal Sciences 164, no. : 106884.

Research article
Published: 18 January 2021 in Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering
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In this paper, in the light of the problems of the traditional air suspension PID controller in the process of body height adjustment, such as the adjustment time is too long, the overshoot phenomenon is obvious, and the control parameters cannot be adjusted in real time, a PID transverse interconnected electronic control air suspension(TIECAS) system controller based on seeker optimization algorithm (SOA) is designed, the proportion factor of PID is optimized by crowd search algorithm and get the optimal solution of PID controller parameters. The control system model is built in [Formula: see text] simulation software. The simulation results show that the PID lateral interconnected air suspension controller based on SOA has faster response and avoids overshoot than the traditional PID controller. The control system was tested on a self-developed test vehicle with TIECAS structure. The test results show that the root mean square(RMS) values of the roll angle and pitch angle of the test vehicle are reduced from [Formula: see text] and [Formula: see text] before control to [Formula: see text] and [Formula: see text], respectively, by [Formula: see text] and [Formula: see text]. The RMS values of the vertical acceleration of the center of mass after control are reduced by [Formula: see text] and [Formula: see text] compared with that without control, effectively improve the ride comfort and operation stability of the vehicle, The research results provide a new idea for the control of the vehicle transverse interconnected electronic air suspension system.

ACS Style

Kai Cao; Zhiqiang Li; Yili Gu; Liuyang Zhang; Liqing Chen. The control design of transverse interconnected electronic control air suspension based on seeker optimization algorithm. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 2021, 235, 2200 -2211.

AMA Style

Kai Cao, Zhiqiang Li, Yili Gu, Liuyang Zhang, Liqing Chen. The control design of transverse interconnected electronic control air suspension based on seeker optimization algorithm. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. 2021; 235 (8):2200-2211.

Chicago/Turabian Style

Kai Cao; Zhiqiang Li; Yili Gu; Liuyang Zhang; Liqing Chen. 2021. "The control design of transverse interconnected electronic control air suspension based on seeker optimization algorithm." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 235, no. 8: 2200-2211.

Research article
Published: 17 January 2021 in Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering
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Due to the considerable increase in car parc and the remarkable improvement in vehicle properties and cost performance, higher requirements are being placed on driving comfort. With regard to the braking system, the enhancement of the brake pedal feel is one of the ways to improve the comfort, and affecting factors include spatial layout, dynamic characteristics, and the characteristics matching with the vehicle motion, so a comprehensive evaluation of a brake pedal is highly essential. This paper, by taking passenger cars in China as the research object, established a comprehensive evaluation system for pedals based on the improved analytic hierarchy process. The index weight in each index level was determined through the G1 method, and an experimental design was conducted on individual indices on the lowest level. The relationship parameters between the indices were measured through the test and comprehensive scores of each automobile pedal were obtained in combination with the evaluation method designed. Based on comprehensive scores, a typical analysis on 16 test vehicles was carried out, followed by a comparison of different index levels. Through result analysis, the direction for pedal improvement was proposed, and the feasibility of the method with the case is verified, which provides a scientific basis and a reference for vehicle pedal development, the calibration in position layout, and the pedal design.

ACS Style

Yili Gu; JinJie Xie; Hongji Liu; Yang Yang; Yudian Tan; Liqing Chen. Evaluation and analysis of comprehensive performance of a brake pedal based on an improved analytic hierarchy process. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 2021, 235, 2636 -2648.

AMA Style

Yili Gu, JinJie Xie, Hongji Liu, Yang Yang, Yudian Tan, Liqing Chen. Evaluation and analysis of comprehensive performance of a brake pedal based on an improved analytic hierarchy process. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. 2021; 235 (9):2636-2648.

Chicago/Turabian Style

Yili Gu; JinJie Xie; Hongji Liu; Yang Yang; Yudian Tan; Liqing Chen. 2021. "Evaluation and analysis of comprehensive performance of a brake pedal based on an improved analytic hierarchy process." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 235, no. 9: 2636-2648.

Article
Published: 30 November 2020 in Journal of Materials Engineering and Performance
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We describe here structure–mechanical property–formability relationships for 444-type ferritic stainless steels with different contents of W. The microstructure, texture and grain boundary character that evolved during hot rolling, cold rolling and annealing process were characterized in detail to predict the effect of W. The microstructure of annealed plates became more uniform and finer with the increase in W content, which led to an increase in both strength and elongation. Alloying with W significantly influenced texture development and texture intensity. The addition of W accelerated the transformation of rolling texture to stable components benefitting the formation of recrystallized γ-fiber texture, and also effectively restrained the deviation from the exact γ-fiber after cold rolling and annealing. Ferritic steel with 1.12 wt.% W exhibited excellent formability because of the presence of intense γ-fiber texture and fine recrystallized grains.

ACS Style

Houlong Liu; Jiahao Zheng; Mingyu Ma; Liangliang Wei; Liqing Chen. Structure–Mechanical Property–Formability Relationships for 444-Type W-Containing Ferritic Stainless Steels. Journal of Materials Engineering and Performance 2020, 30, 467 -478.

AMA Style

Houlong Liu, Jiahao Zheng, Mingyu Ma, Liangliang Wei, Liqing Chen. Structure–Mechanical Property–Formability Relationships for 444-Type W-Containing Ferritic Stainless Steels. Journal of Materials Engineering and Performance. 2020; 30 (1):467-478.

Chicago/Turabian Style

Houlong Liu; Jiahao Zheng; Mingyu Ma; Liangliang Wei; Liqing Chen. 2020. "Structure–Mechanical Property–Formability Relationships for 444-Type W-Containing Ferritic Stainless Steels." Journal of Materials Engineering and Performance 30, no. 1: 467-478.

Journal article
Published: 23 November 2020 in Metals
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High quality products are demanded due to increasingly fierce market competition. In this paper, the generation of surface wrinkle defect of welding wire steel ER70S-6 was studied by the combination of the experimental method and finite element simulation. Firstly, a thermal compression test was conducted on the Gleeble-3500 thermosimulator under different strain rates and temperatures and a strain dependent Arrhenius-type constitutive function was employed to fit the flow stress–strain curves obtained from the experiments. Then, the elastoplastic constitutive relationship was implemented using radial return mapping algorithm by means of the user subroutine VUMAT of Abaqus/Explicit. A new instability criterion was proposed to predict the possibility of the surface wrinkle defect during the multipass hot bar rolling process. In order to verify the reliability of the finite element model of the six-pass continuous rolling process, the simulated results were compared with experimental data. Finally, the effects of groove width and groove radius on the billet were investigated by the orthogonal test method, and the friction coefficient and rolling temperature. The results show that the groove width and groove radius are key factors to suppress the surface wrinkle defect. Decreasing the groove width can be beneficial for improving the surface quality and reducing the fillet radius. The optimized combination of the rolling process parameters was further applied in an industrial test and the surface quality of the billet was greatly improved.

ACS Style

Qian Liu; Yaqiang Tian; Jinpo Zhai; Lu Tian; Liansheng Chen; Liqing Chen. Prediction of Surface Wrinkle Defect of Welding Wire Steel ER70S-6 in Hot Bar Rolling Process Using Finite Element Method and Experiments. Metals 2020, 10, 1559 .

AMA Style

Qian Liu, Yaqiang Tian, Jinpo Zhai, Lu Tian, Liansheng Chen, Liqing Chen. Prediction of Surface Wrinkle Defect of Welding Wire Steel ER70S-6 in Hot Bar Rolling Process Using Finite Element Method and Experiments. Metals. 2020; 10 (11):1559.

Chicago/Turabian Style

Qian Liu; Yaqiang Tian; Jinpo Zhai; Lu Tian; Liansheng Chen; Liqing Chen. 2020. "Prediction of Surface Wrinkle Defect of Welding Wire Steel ER70S-6 in Hot Bar Rolling Process Using Finite Element Method and Experiments." Metals 10, no. 11: 1559.

Article
Published: 23 November 2020 in Acta Metallurgica Sinica (English Letters)
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In this article, the influence of simulated thermal cycles for the heat-affected zone (HAZ) on the microstructural evolution and mechanical properties in a low-carbon high-strength Cu-bearing steel was investigated by microstructural characterization and mechanical tests. The results showed that the microstructure of the coarse-grained heat-affected zone (CGHAZ) and the fine-grained heat-affected zone (FGHAZ) was mainly comprised of lath martensite, and a mixed microstructure consisting of intercritical ferrite, tempered martensite and retained austenite occurred in the intercritically heat-affected zone (ICHAZ) and the subcritically heat-affected zone (SCHAZ). Also, 8–11% retained austenite and more or less Cu precipitates were observed in the simulated HAZs except for CGHAZ. Charpy impact test indicated that the optimum toughness was obtained in FGHAZ, which was not only associated with grain refinement, but also correlated with deformation-induced transformation of the retained austenite, variant configuration as interleaved type and a relatively weak variant selection. The toughness of ICHAZ and SCHAZ exhibited a slight downtrend due to the presence of Cu precipitates. The CGHAZ has the lowest toughness in the simulated HAZs, which was attributed to grain coarsening and heavy variant selection. In addition, the contribution of Cu precipitates to yield strength in simulated HAZs was estimated based on Russell–Brown model. It demonstrated an inverse variation trend to toughness.

ACS Style

Xiaohui Xi; Jinliang Wang; Liqing Chen; Zhaodong Wang. On the Microstructural Strengthening and Toughening of Heat-Affected Zone in a Low-Carbon High-Strength Cu-Bearing Steel. Acta Metallurgica Sinica (English Letters) 2020, 34, 617 -627.

AMA Style

Xiaohui Xi, Jinliang Wang, Liqing Chen, Zhaodong Wang. On the Microstructural Strengthening and Toughening of Heat-Affected Zone in a Low-Carbon High-Strength Cu-Bearing Steel. Acta Metallurgica Sinica (English Letters). 2020; 34 (5):617-627.

Chicago/Turabian Style

Xiaohui Xi; Jinliang Wang; Liqing Chen; Zhaodong Wang. 2020. "On the Microstructural Strengthening and Toughening of Heat-Affected Zone in a Low-Carbon High-Strength Cu-Bearing Steel." Acta Metallurgica Sinica (English Letters) 34, no. 5: 617-627.

Article
Published: 30 September 2020 in Metallurgical and Materials Transactions A
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To obtain the correlation of microstructural characteristics and toughness in a novel high-strength low-carbon bainitic structural steel with medium and heavy plate after multipass welding, a welding thermal simulation experiment was conducted to simulate different subregions in the reheated coarse-grained heat-affected zones (CGHAZ). The microstructure evolution was then analyzed and factors that influence the fracture behavior were studied. The results show that the brittle zone appeared in subcritical reheated CGHAZ, and the fractured morphology was cleavage fracture. Supercritical reheated CGHAZ had the highest impact toughness, and the fractured morphology was primarily the ductile fracture with dimples formed via the micropore polycondensation mechanism. With an increase in the secondary pass welding thermal cycle peak temperature (tp2), the average length size of martensite and austenite (M-A) decreased from 9 to 2 μm. The coarsening of M-A constituents was the main reason for decrease in the crack initiation absorbed energy. A large number of retained austenite and cementite precipitates in subcritical reheated CGHAZ clearly worsened the impact toughness, and the massive austenite and cementite precipitates more than offset the beneficial effects of high-angle boundaries. This phenomenon led to disappearance of the effect of high-angle grain boundary of prior austenite and lath bainite on arresting crack propagation. In supercritical reheated CGHAZ, crack propagation absorbed energy was increased because of grain refinement, fine precipitates, lamellar residual austenite at corners, and high-angle grain boundary.

ACS Style

Junjun Cui; Wenting Zhu; Zhenye Chen; Liqing Chen. Microstructural Characteristics and Impact Fracture Behaviors of a Novel High-Strength Low-Carbon Bainitic Steel with Different Reheated Coarse-Grained Heat-Affected Zones. Metallurgical and Materials Transactions A 2020, 51, 6258 -6268.

AMA Style

Junjun Cui, Wenting Zhu, Zhenye Chen, Liqing Chen. Microstructural Characteristics and Impact Fracture Behaviors of a Novel High-Strength Low-Carbon Bainitic Steel with Different Reheated Coarse-Grained Heat-Affected Zones. Metallurgical and Materials Transactions A. 2020; 51 (12):6258-6268.

Chicago/Turabian Style

Junjun Cui; Wenting Zhu; Zhenye Chen; Liqing Chen. 2020. "Microstructural Characteristics and Impact Fracture Behaviors of a Novel High-Strength Low-Carbon Bainitic Steel with Different Reheated Coarse-Grained Heat-Affected Zones." Metallurgical and Materials Transactions A 51, no. 12: 6258-6268.

Journal article
Published: 19 June 2020 in International Journal of Heat and Mass Transfer
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This study proposes a torque calculation model that incorporates the boundary conditions of the lubricant flow field and variation of oil film temperature. The lubricating oil not only has the function of transferring torque, and the heat exchange between the lubricating oil and the friction plate will also cause the changes in lubrication characteristics. The torque transfer equation of a multi-plate clutch as related to viscosity was derived by combining the three-dimensional Navier-Stokes equation with the boundary conditions of the lubricant flow field. Considering the impact of the heat dissipation of the flow field into the torque transfer of the multi-plate clutch, the traditional torque transmission equation was modified with a piecewise affine (PWA) method. Taking the vehicle transfer case as an example, the equation for the variation in oil film radial temperature was obtained through the thermodynamic model of a flow field. By applying the parameters derived from the temperature equation to the PWA torque transfer model, the values under four working conditions were calculated. The results show that the relative errors between the corrected torque value and the test value under the four working conditions were less than 10%. The formation of the torque stability value provided by the PWA torque transfer model was at least about 0.1s earlier than that of the conventional model and much closer to the test result. Thus, the PWA torque calculation model performed well in the calculation of transmission torque.

ACS Style

Xiutian Liang; Liqing Chen; Yuming Wang; Ling Wan. A proposed torque calculation model for multi-plate clutch considering boundary lubrication conditions and heat transfer. International Journal of Heat and Mass Transfer 2020, 157, 119732 .

AMA Style

Xiutian Liang, Liqing Chen, Yuming Wang, Ling Wan. A proposed torque calculation model for multi-plate clutch considering boundary lubrication conditions and heat transfer. International Journal of Heat and Mass Transfer. 2020; 157 ():119732.

Chicago/Turabian Style

Xiutian Liang; Liqing Chen; Yuming Wang; Ling Wan. 2020. "A proposed torque calculation model for multi-plate clutch considering boundary lubrication conditions and heat transfer." International Journal of Heat and Mass Transfer 157, no. : 119732.

Metals and corrosion
Published: 30 April 2020 in Journal of Materials Science
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In this article, the coarse grained heat affected zone (CGHAZ) of a low carbon high strength steel was simulated at two heat inputs on a Gleeble-3800 thermo-mechanical simulator. A comparative study was conducted to reveal the role of Cu addition in toughness improvement by microstructure characterization and Charpy impact test. Microstructure observation suggested that there is no observable difference in the microstructure and prior austenite grain size between Cu-free steel and Cu-bearing steel, but a higher density of high-angle grain boundary (HAGB) was obtained in Cu-bearing steel with 50 kJ/cm. This was intrinsically associated with the configuration of three Bain groups from the aspect of crystallography. The optimum configuration can be achieved by adjusting transformation driving force, cooling rate and nucleation characteristics during martensite/bainite transformation. In this study, Cu addition played a determining role in increasing transformation driving force at high cooling rate, and altering the diffusion kinetics of alloying elements at low cooling rate. Accordingly, the density of HAGB can be optimized to be beneficial for high toughness in CGHAZ. Therefore, the optimum toughness was obtained in Cu-bearing steel with heat input of 50 kJ/cm, which was featured by the impact energy of ~ 198 J at − 40 °C.

ACS Style

Xiaohui Xi; Jinliang Wang; Liqing Chen; Zhaodong Wang. On the role of Cu addition in toughness improvement of coarse grained heat affected zone in a low carbon high strength steel. Journal of Materials Science 2020, 55, 10863 -10877.

AMA Style

Xiaohui Xi, Jinliang Wang, Liqing Chen, Zhaodong Wang. On the role of Cu addition in toughness improvement of coarse grained heat affected zone in a low carbon high strength steel. Journal of Materials Science. 2020; 55 (24):10863-10877.

Chicago/Turabian Style

Xiaohui Xi; Jinliang Wang; Liqing Chen; Zhaodong Wang. 2020. "On the role of Cu addition in toughness improvement of coarse grained heat affected zone in a low carbon high strength steel." Journal of Materials Science 55, no. 24: 10863-10877.

Communication
Published: 19 April 2020 in Metallurgical and Materials Transactions A
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We elucidate here the effect of tungsten on grain refinement in the HAZ of ferritic stainless steels (FSSs) at 1200 °C and 1350 °C. The average simulated HAZ grain size of W-containing FSS (1.5 wt. pct W) was reduced by ~ 50 pct compared to W-free FSS at 1350 °C. The replacement of Mo with W in FSSs enhanced the thermal stability of Laves phase at high temperatures and contributed to fine grain size in the HAZ via pinning effect.

ACS Style

Liangliang Wei; Liqing Chen; Houlong Liu; R. D. K. Misra. Significant Grain Refinement in the Simulated Heat-Affected Zone (HAZ) of Ferritic Stainless Steels by Alloying with Tungsten. Metallurgical and Materials Transactions A 2020, 51, 2719 -2723.

AMA Style

Liangliang Wei, Liqing Chen, Houlong Liu, R. D. K. Misra. Significant Grain Refinement in the Simulated Heat-Affected Zone (HAZ) of Ferritic Stainless Steels by Alloying with Tungsten. Metallurgical and Materials Transactions A. 2020; 51 (6):2719-2723.

Chicago/Turabian Style

Liangliang Wei; Liqing Chen; Houlong Liu; R. D. K. Misra. 2020. "Significant Grain Refinement in the Simulated Heat-Affected Zone (HAZ) of Ferritic Stainless Steels by Alloying with Tungsten." Metallurgical and Materials Transactions A 51, no. 6: 2719-2723.

Article
Published: 31 March 2020 in Acta Metallurgica Sinica (English Letters)
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A 444-type heat-resistant ferritic stainless steel containing 0.05 wt% Ce (rare earth element) and 2 wt% (Mo + W) was adopted as an experimental material to study the effect of finish rolling temperature on microstructure and texture evolution as well as on mechanical properties and formability. The rolling processes contain hot rolling at two different finish rolling temperatures (860 °C and 770 °C) and annealing, cold rolling and subsequent annealing. It was found that the microstructures after hot rolling and annealing could be refined by lowering finish rolling temperature. The resultant microstructures after cold rolling and annealing were hereditarily refined. Lowering finish rolling temperature can weaken α-fiber texture in hot-rolled or cold-rolled ferritic stainless steel strip, while γ-fiber texture in the final product was homogeneously strengthened. Additionally, enhanced mechanical property and formability in terms of strength and average plastic strain ratio could be obtained via decreasing finish rolling temperature.

ACS Style

Hou-Long Liu; Ling-Ling Liu; Ming-Yu Ma; Li-Qing Chen. Influence of Finish Rolling Temperature on Microstructure and Mechanical Properties of a 19Cr1.5Mo0.5 W Ferritic Stainless Steel. Acta Metallurgica Sinica (English Letters) 2020, 33, 991 -1000.

AMA Style

Hou-Long Liu, Ling-Ling Liu, Ming-Yu Ma, Li-Qing Chen. Influence of Finish Rolling Temperature on Microstructure and Mechanical Properties of a 19Cr1.5Mo0.5 W Ferritic Stainless Steel. Acta Metallurgica Sinica (English Letters). 2020; 33 (7):991-1000.

Chicago/Turabian Style

Hou-Long Liu; Ling-Ling Liu; Ming-Yu Ma; Li-Qing Chen. 2020. "Influence of Finish Rolling Temperature on Microstructure and Mechanical Properties of a 19Cr1.5Mo0.5 W Ferritic Stainless Steel." Acta Metallurgica Sinica (English Letters) 33, no. 7: 991-1000.

Journal article
Published: 31 January 2020 in Sensors
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Due to the narrow row spacing of corn, the lack of light in the field caused by the blocking of branches, leaves and weeds in the middle and late stages of corn growth, it is generally difficult for machinery to move between rows and also impossible to observe the corn growth in real time. To solve the problem, a robot for corn interlines information collection thus is designed. First, the mathematical model of the robot is established using the designed control system. Second, an improved convolutional neural network model is proposed for training and learning, and the driving path is fitted by detecting and identifying corn rhizomes. Next, a multi-body dynamics simulation software, RecurDyn/track, is used to establish a dynamic model of the robot movement in soft soil conditions, and a control system is developed in MATLAB/SIMULINK for joint simulation experiments. Simulation results show that the method for controlling a sliding-mode variable structure can achieve better control results. Finally, experiments on the ground and in a simulated field environment show that the robot for field information collection based on the method developed runs stably and shows little deviation. The robot can be well applied for field plant protection, the control of corn diseases and insect pests, and the realization of human–machine separation.

ACS Style

Yili Gu; Zhiqiang Li; Zhen Zhang; Jun Li; Liqing Chen; Li. Path Tracking Control of Field Information-Collecting Robot Based on Improved Convolutional Neural Network Algorithm. Sensors 2020, 20, 797 .

AMA Style

Yili Gu, Zhiqiang Li, Zhen Zhang, Jun Li, Liqing Chen, Li. Path Tracking Control of Field Information-Collecting Robot Based on Improved Convolutional Neural Network Algorithm. Sensors. 2020; 20 (3):797.

Chicago/Turabian Style

Yili Gu; Zhiqiang Li; Zhen Zhang; Jun Li; Liqing Chen; Li. 2020. "Path Tracking Control of Field Information-Collecting Robot Based on Improved Convolutional Neural Network Algorithm." Sensors 20, no. 3: 797.

Original paper
Published: 06 January 2020 in Oxidation of Metals
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Anti-corrosion behavior of Fe–Cr alloys at elevated temperature is greatly influenced by the protective nature of oxide scale formed on them. However, precipitates formed underneath the scale can affect the diffusion of reactive elements, growth mechanism and failure mechanism of oxide film. Here, we elucidate the precipitation mechanism of Laves phase in the vicinity of oxide film during oxidation at 950–1050 °C in air. Two types of automotive exhaust manifold-used ferritic stainless steels were designed by replacing Mo with different contents of W and adding small content of Ce. By systematic investigations of the precipitates in the vicinity of steel/oxide interface, we conclude that Laves phase precipitated near the oxide film is related to the selective oxidation of chromium, which is dramatically different from conventional precipitation mechanism. Nb was localized at the interface due to rejection from the growing Cr2O3 scale, which promoted the formation of Laves phase. The experimental steels were characterized by excellent oxidation resistance and Ti–rich oxide formed in the internal oxidation zone that hindered the further diffusion of oxygen.

ACS Style

Liangliang Wei; Liqing Chen; Houlong Liu; Liqiang Han; Na Gong; R. D. K. Misra. Precipitation Behavior of Laves Phase in the Vicinity of Oxide Film of Ferritic Stainless Steel: Selective Oxidation-Induced Precipitation. Oxidation of Metals 2020, 93, 195 -213.

AMA Style

Liangliang Wei, Liqing Chen, Houlong Liu, Liqiang Han, Na Gong, R. D. K. Misra. Precipitation Behavior of Laves Phase in the Vicinity of Oxide Film of Ferritic Stainless Steel: Selective Oxidation-Induced Precipitation. Oxidation of Metals. 2020; 93 (1-2):195-213.

Chicago/Turabian Style

Liangliang Wei; Liqing Chen; Houlong Liu; Liqiang Han; Na Gong; R. D. K. Misra. 2020. "Precipitation Behavior of Laves Phase in the Vicinity of Oxide Film of Ferritic Stainless Steel: Selective Oxidation-Induced Precipitation." Oxidation of Metals 93, no. 1-2: 195-213.

Journal article
Published: 01 January 2020 in International Journal of Agricultural and Biological Engineering
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In order to solve the problem of interaction between multiple evaluation indexes of seed metering performance under multiple factors of centralized seed feeding device, a multi-objective optimization of structure based on particle swarm optimization (PSO) algorithm was proposed in this paper. The wheat centralized seed feeding device was taken as the research object, and the experimental factors were cone angle of type hole, working speed and seed filling gap. The working process of wheat centralized seed feeding device was simulated by discrete element method (DEM). The average seed number of type hole, the variation coefficient of the average seed number of type hole, and the maximum tangential force between seed and seed feeding mechanism were selected as the evaluation indexes. Through the variance analysis of the evaluation indexes by the experimental factors, the optimization objective function was constructed. Using PSO algorithm, the multi-objective optimization was carried out for the wheat centralized seed feeding device. The optimization results show that the best structural combination parameters of the wheat centralized seed feeding device are the hole cone angle of 31.6° and the seed filling gap of 4.6 mm. The validity of the method was verified by simulation and field test. The results show that the PSO algorithm multi-objective optimization method proposed in this paper can provide a reference for the structural improvement and optimal design of the centralized seed feeding device. Keywords: centralized seed feeding device, multi-objective, optimization, PSO algorithm DOI: 10.25165/j.ijabe.20201306.5665 Citation: Wang Q Q, Li Z D, Wang W W, Zhang C L, Chen L Q, Wan L. Multi-objective optimization design of wheat centralized seed feeding device based on particle swarm optimization (PSO) algorithm. Int J Agric & Biol Eng, 2020; 13(6): 76–84.

ACS Style

Qingqing Wang; Zhaodong Li; Weiwei Wang; Chunling Zhang; Liqing Chen; Ling Wan. Multi-objective optimization design of wheat centralized seed feeding device based on particle swarm optimization (PSO) algorithm. International Journal of Agricultural and Biological Engineering 2020, 13, 76 -84.

AMA Style

Qingqing Wang, Zhaodong Li, Weiwei Wang, Chunling Zhang, Liqing Chen, Ling Wan. Multi-objective optimization design of wheat centralized seed feeding device based on particle swarm optimization (PSO) algorithm. International Journal of Agricultural and Biological Engineering. 2020; 13 (6):76-84.

Chicago/Turabian Style

Qingqing Wang; Zhaodong Li; Weiwei Wang; Chunling Zhang; Liqing Chen; Ling Wan. 2020. "Multi-objective optimization design of wheat centralized seed feeding device based on particle swarm optimization (PSO) algorithm." International Journal of Agricultural and Biological Engineering 13, no. 6: 76-84.

Journal article
Published: 26 December 2019 in Journal of Materials Research and Technology
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Small-size Laves phase precipitates have the advantage of providing superior high-temperature properties to ferritic stainless steels. However, the coarsening of precipitates becomes inevitable during long-term service at elevated temperatures, which causes degradation of high-temperature strength and thermal fatigue resistance. In this study, Laves phase precipitation behavior and high-temperature strength is elucidated in W-containing ferritic stainless steels in the temperature range of 800–1100 °C. Laves phase preferentially precipitated at the grain boundaries and were uniformly dispersed within the grains after aging. The intragranular Laves phase almost completely vanished and only intergranular precipitates were present after long-term aging, especially at 900–1000 °C. The W-containing steels exhibited higher tensile strength than W-free steel, which resulted from the formation of Laves phase at higher temperatures and solid-solution strengthening effect. Nevertheless, the size of Laves phase was increased with the increase of W content, which led to the decrease of precipitation strengthening effect after long-term aging. This change resulted in the apparent reduction of tensile strength with increased aging time, although the W-containing steels continued to exhibit higher tensile strength compared to W-free steel.

ACS Style

Houlong Liu; Liangliang Wei; Mingyu Ma; Jiahao Zheng; Liqing Chen; Raja Devesh Kumar Misra. Laves phase precipitation behavior and high-temperature strength of W-containing ferritic stainless steels. Journal of Materials Research and Technology 2019, 9, 2127 -2135.

AMA Style

Houlong Liu, Liangliang Wei, Mingyu Ma, Jiahao Zheng, Liqing Chen, Raja Devesh Kumar Misra. Laves phase precipitation behavior and high-temperature strength of W-containing ferritic stainless steels. Journal of Materials Research and Technology. 2019; 9 (2):2127-2135.

Chicago/Turabian Style

Houlong Liu; Liangliang Wei; Mingyu Ma; Jiahao Zheng; Liqing Chen; Raja Devesh Kumar Misra. 2019. "Laves phase precipitation behavior and high-temperature strength of W-containing ferritic stainless steels." Journal of Materials Research and Technology 9, no. 2: 2127-2135.

Article
Published: 11 October 2019 in Metallurgical and Materials Transactions A
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In this work, the effect of Cu addition on the microstructure and mechanical properties, in particular, low-temperature toughness, of low-carbon, high-strength steel was investigated. Steels with Cu concentrations varying from 1 to 2.5 wt pct in the place of carbon were prepared and then subjected to the two-step intercritical heat treatment. A mixed microstructure consisting of intercritical ferrite, tempered martensite, and retained austenite was obtained. There was an increased amount of retained austenite in the steels with Cu contents ranging from 0.23 to 2.5 wt pct. Therefore, Cu addition was beneficial for the stabilization of retained austenite. This phenomenon can be attributed to the enrichment of Cu in austenite and the increased driving force of reversed transformation caused by reduction in the T0 temperature (the temperature at which fcc austenite and bcc ferrite of identical composition have equal free energy). Furthermore, nanoscaled Cu precipitates were dispersed in the microstructure of Cu-containing steels. The combined effect of retained austenite and Cu precipitates could be the reason for excellent low-temperature toughness without loss in strength, which is featured by the impact energy of more than 120 J at 153 K (– 120 °C) for the Cu-containing steels. In addition to the deformation-induced transformation of retained austenite, bcc Cu precipitates act as misfit centers to improve the low-temperature toughness by enhancing the dislocation mobility and decreasing the ductile-to-brittle transformation temperature (DBTT).

ACS Style

Xiaohui Xi; Jinliang Wang; Liqing Chen; Zhaodong Wang. Understanding the Role of Copper Addition in Low-Temperature Toughness of Low-Carbon, High-Strength Steel. Metallurgical and Materials Transactions A 2019, 50, 5627 -5639.

AMA Style

Xiaohui Xi, Jinliang Wang, Liqing Chen, Zhaodong Wang. Understanding the Role of Copper Addition in Low-Temperature Toughness of Low-Carbon, High-Strength Steel. Metallurgical and Materials Transactions A. 2019; 50 (12):5627-5639.

Chicago/Turabian Style

Xiaohui Xi; Jinliang Wang; Liqing Chen; Zhaodong Wang. 2019. "Understanding the Role of Copper Addition in Low-Temperature Toughness of Low-Carbon, High-Strength Steel." Metallurgical and Materials Transactions A 50, no. 12: 5627-5639.

Research article
Published: 27 September 2019 in Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering
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Existing research on the manipulation comfort of the cab pedal generally focuses on the completion of the pedal movement when a vehicle is at rest, with certain data collected for analysis. This paper, by taking passenger vehicles in China as the study object and in view of the actual road conditions in China and the Chinese body size, attempts to solve the problem of muscle redundancy through the maximum/minimum optimization model of muscle activation. The road test was carried out on a typical pavement in a Chinese city. The parameters of pedal stroke, pedal force, and typical Electromyography signal (EMG) signal of drivers’ lower limbs during driving were obtained, from which muscle activation degree was calculated. The obtained experimental data were used as external driving one to simulate and analyze the pedal comfort under the layout of different human percentile and different pedal parameters in an aim to obtain the optimal value. The results indicate that the difference in pedal strokes, pedal preload, pedal resistance coefficients, seat heights, and H-point distances can have a noticeable effect on muscle activation. Taking a 95th-percentile accelerator pedal as an example, with the optimal values of each parameter selected (pedal preload: 8.2 N, pedal resistance coefficient: 2.55, seat height: 0.45 m and H-point distance: 0.86 m), as the pedal strokes increase, muscle activation shows a trend of increase after initial decrease. In the common stroke of a pedal after optimization, the degree of muscle activation is significantly lower than that before optimization, indicating a decrease in muscle fatigue.

ACS Style

Liqing Chen; Wanjun Li; Yang Yang; Wei Miao. Evaluation and optimization of vehicle pedal comfort based on biomechanics. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 2019, 234, 1402 -1412.

AMA Style

Liqing Chen, Wanjun Li, Yang Yang, Wei Miao. Evaluation and optimization of vehicle pedal comfort based on biomechanics. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. 2019; 234 (5):1402-1412.

Chicago/Turabian Style

Liqing Chen; Wanjun Li; Yang Yang; Wei Miao. 2019. "Evaluation and optimization of vehicle pedal comfort based on biomechanics." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, no. 5: 1402-1412.