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Characterization and Analysis of Inconel 718 Alloy Ground at Different Speeds

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Chinese Journal of mechanical engineering 2024年第2期37卷 137-149页

作者： Hao Liu Huili Han Qinghong Jiang Minglin He Bi Zhang department of mechanical and Energy engineering Southern University of Science and TechnologyShenzhen 518055China department of mechanical engineering Hong Kong Polytechnic UniversityHong KongChina

Inconel 718(IN718)alloy is widely applied to fabricate high temperature resistant or corrosion resistant parts due to its excellent mechanical ***,the machining of IN718 alloy is difficult as it may cause serious tool wear and poor surface quality(SQ)of the *** this work,grinding experiments on IN718 alloy at different speeds were conducted by using a CBN grinding *** relationship between grinding speed,SQ and subsurface damage(SSD)was well *** increasing grinding speed,surface roughness decreased,and SQ was greatly ***,the microhardness of the grinding surface declined as the grinding speed *** SSD depth was almost unchanged when the grinding speed was lower than 15 m/s,then it decreased with higher grinding *** was attributed to the mechanical-thermal synergistic effect in the grinding *** results indicated that increasing grinding speed can effectively improve the SQ and reduce the SSD of IN718 *** conclusion in the work may also provide insight into processing other hard-to-machining materials.

关键词： Surface integrity Grinding speed IN718 alloy Precision machining CBN grinding wheel

Adaptive state-constrained/model-free iterative sliding mode control for aerial robot trajectory tracking

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 603-618页

作者： Chen AN Jiaxi ZHOU Kai WANG College of mechanical and Vehicle engineering Hunan UniversityChangsha 410082China department of mechanical engineering The Hong Kong Polytechnic UniversityHong KongChina

This paper develops a novel hierarchical control strategy for improving the trajectory tracking capability of aerial robots under parameter *** hierarchical control strategy is composed of an adaptive sliding mode controller and a model-free iterative sliding mode controller(MFISMC).A position controller is designed based on adaptive sliding mode control(SMC)to safely drive the aerial robot and ensure fast state convergence under external ***,the MFISMC acts as an attitude controller to estimate the unmodeled dynamics without detailed knowledge of aerial ***,the adaption laws are derived with the Lyapunov theory to guarantee the asymptotic tracking of the system ***,to demonstrate the performance and robustness of the proposed control strategy,numerical simulations are carried out,which are also compared with other conventional strategies,such as proportional-integralderivative(PID),backstepping(BS),and *** simulation results indicate that the proposed hierarchical control strategy can fulfill zero steady-state error and achieve faster convergence compared with conventional strategies.

关键词： aerial robot hierarchical control strategy model-free iterative sliding mode controller(MFISMC) trajectory tracking reinforcement learning

Nickel Sulfide Modified NiCu Nanoalloy with Excellent Oxygen Evolution Reaction Properties Prepared through Electrospinning and Heat Treatment

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 320-326页

作者：李涛凌帅 ZHONG Shujie LOU Qiongyue department of Materials engineering School of Mechanical EngineeringChengdu UniversityChengdu 610106China

Ni^(2+)/Cu^(2+)/SO_(4)^(2-)/polyvinyl alcohol precursor fibers with uniform diameters were prepared through ***-based composite nanoalloys containing Ni,Cu,and S were prepared through heat treatment in an Ar *** experimental results show that the main components of the prepared nanoalloys are NiCu,Ni_(3)S_(2),Ni,and *** nanoalloys exhibit fine grain sizes about 200-500 nm,which can increase with increasing heat treatment *** test results show that the nickel sulfidemodified NiCu nanoalloy composites exhibit excellent oxygen evolution reaction properties,and the oxygen evolution reaction properties gradually improve with the increasing heat treatment *** sample prepared at 1 000℃ for 40 min show a low overpotential of 423 mV and a small Tafel slope of 134 mV·dec^(-1) at a current density of 10 mA·cm^(-2).

关键词： NiCu nanoalloy Ni_(3)S_(2) structure transformation oxygen evolution reaction

Battery pack capacity estimation for electric vehicles based on enhanced machine learning and field data

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Journal of Energy Chemistry 2024年第5期92卷 605-618页

作者： Qingguang Qi Wenxue Liu Zhongwei Deng Jinwen Li Ziyou Song Xiaosong Hu College of mechanical and Vehicle engineering Chongqing UniversityChongqing 400044China School of mechanical and Electrical engineering University of Electronic Science and Technology of ChinaChengdu 611731SichuanChina department of mechanical engineering National University of SingaporeSingapore 117575Singapore

Accurate capacity estimation is of great importance for the reliable state monitoring,timely maintenance,and second-life utilization of lithium-ion *** numerous works on battery capacity estimation using laboratory datasets,most of them are applied to battery cells and lack satisfactory fidelity when extended to real-world electric vehicle(EV)battery *** challenges intensify for large-sized EV battery packs,where unpredictable operating profiles and low-quality data acquisition hinder precise capacity *** fill the gap,this study introduces a novel data-driven battery pack capacity estimation method grounded in field *** proposed approach begins by determining labeled capacity through an innovative combination of the inverse ampere-hour integral,open circuit voltage-based,and resistance-based correction ***,multiple health features are extracted from incremental capacity curves,voltage curves,equivalent circuit model parameters,and operating temperature to thoroughly characterize battery aging behavior.A feature selection procedure is performed to determine the optimal feature set based on the Pearson correlation ***,a convolutional neural network and bidirectional gated recurrent unit,enhanced by an attention mechanism,are employed to estimate the battery pack capacity in real-world EV ***,the proposed method is validated with a field dataset from two EVs,covering approximately 35,000 *** results demonstrate that the proposed method exhibits better estimation performance with an error of less than 1.1%compared to existing *** work shows great potential for accurate large-sized EV battery pack capacity estimation based on field data,which provides significant insights into reliable labeled capacity calculation,effective features extraction,and machine learning-enabled health diagnosis.

关键词： Electricvehicle Lithium-ion battery pack Capacity estimation Machine learning Field data

Investigation on the Velocity-Dependent Adhesion Hysteresis via Molecular Dynamics Simulation

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Acta Mechanica Solida Sinica 2024年第3期37卷 423-429页

作者： Jinshan He Yiran Li Zhaoyang Ma Ganyun Huang department of Mechanics School of Mechanical EngineeringTianjin UniversityTianjin300350China

Adhesion plays an important role in miniaturized devices and technologies,which depends not only on indentation depth but also on the history of contact making and breaking,giving rise to adhesion *** the present work,adhesion hysteresis has been investigated via molecular dynamics simulations on approaching and retracting a rigid tip to and from a *** results show that hysteresis in the force-displacement curve that depends on approaching and retraction velocities arises under both elastic and plastic *** underlying mechanisms have been *** implications of the results in friction have been discussed briefly.

关键词： Adhesion hysteresis Molecular dynamics simulation Contact instability Plastic deformation

Self-Adaptive and Electric Field-Driven Protective Layer with Anchored Lithium Deposition Enable Stable Lithium Metal Anode

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Energy & Environmental Materials 2024年第3期7卷 32-40页

作者： Ting Chen Luchao Yue Guoqiang Shu Qing Yang Dong Wang Ruoyang Wang Xianyan Qiao Yan Sun Benhe Zhong Zhenguo Wu Xiaodong Guo department of Chemical engineering Sichuan UniversityChengdu 610065China School of mechanical engineering Chengdu UniversityChengdu 610106China

Lithium metal battery has great development potential because of its lowest electrochemical potential and highest theoretical ***,the uneven deposition of Li^(+)flux in the process of deposition and stripping induces the vigorous growth of lithium dendrites,which results in severely battery performance degradation and serious safety ***,the tetragonal BaTiO3 polarized by high voltage corona was used to build an artificial protective layer with uniform positive polarization direction,which enables uniform Li^(+)*** contrast to traditional strategies of using protective layer,which can guide the uniform deposition of lithium *** ferroelectric protective layer can accurately anchor the Li^(+)and achieve bottom deposition of lithium due to the automatic adjustment of the electric ***,the huge volume changes caused by Li^(+)migration change of the lithium metal anode during charging and discharging is functioned to excite the piezoelectric effect of the protective layer,and achieve seamless dynamic tuning of lithium deposition/*** dynamic effect can accurately anchor and capture Li^(+).Finally,the layer-modified Li anode enables reversible Li plating/stripping over 1500 h at 1 mA cm^(-2)and 50℃in symmetric *** addition,the assembled Li-S full cell exhibits over 300 cycles with N/P≈*** work provides a new perspective on the uniform Li^(+)flux at the Li-anode interface of the artificial protective layer.

关键词： dense plating/stripping process electric field ferroelectric materials lithium metal batteries solid electrolyte interphase

Rapid surface texturing to achieve robust superhydrophobicity,controllable droplet impact,and anti-frosting performances

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Friction 2024年第2期12卷 291-304页

作者： Qingwen DAI Lei CHEN Jiabao PAN Liping SHI Dameng LIU Wei HUANG Xiaolei WANG College of mechanical and Electrical engineering Nanjing University of Aeronautics&AstronauticsNanjing 210016China State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China School of mechanical engineering Anhui Polytechnic UniversityWuhu 241000China School of mechanical engineering Anhui University of TechnologyMa’anshan 243032China

Robust superhydrophobic surfaces with excellent capacities of repelling water and anti-frosting are of importance for many mechanical *** this work,wear-resistant superhydrophobic surfaces were fabricated by curing a mixture of polyurethane acrylate(PUA)coating and 1H,1H,2H,2H-Perfluorodecyltrichlorosilane(HFTCS)on titanium alloy(TC4)surfaces decorated with micropillars pattern,thus,composite functional surfaces with PUA coating in the valleys around the micropillars pattern of TC4 were *** contact angle on fabricated surfaces could reach 167°.Influences of the geometric parameters of micropillars pattern on the apparent contact angle were investigated,and the corresponding wear-resistant property was *** impact and anti-frosting performances on the prepared surfaces were *** optimized design of surface texture with robust superhydrophobicity,controllable droplet impact,and anti-frosting performances was *** design principle is of promising prospects for fabricating superhydrophobic surfaces in traditional mechanical systems.

关键词： surface texture robust superhydrophobic wear-resistant droplet impact anti-frosting

Machine learning enabling prediction in mechanical performance of Ti6Al4V fabricated by large-scale laser powder bed fusion via a stacking model

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Frontiers of mechanical engineering 2024年第4期19卷 29-43页

作者： Changjun HAN Fubao YAN Daolin YUAN Kai LI Yongqiang YANG Jiong ZHANG Di WANG School of mechanical and Automotive engineering South China University of TechnologyGuangzhou 510641China department of mechanical engineering College of EngineeringCity University of Hong KongHong Kong 999077China

Determining appropriate process parameters in large-scale laser powder bed fusion(LPBF)additive manufacturing pose formidable challenges that necessitate advanced approaches to minimize trial-and-error during *** work proposed a data-driven approach based on stacking ensemble learning to predict the mechanical properties of Ti6Al4V alloy fabricated by large-scale LPBF for the first *** method can adapt to the complexity of large-scale LPBF data distribution and exhibits a more generalized predictive capability compared to base ***,the stacking model utilized artificial neural network(ANN),gradient boosting regressor,kernel ridge regression,and elastic net as base models,with the Lasso model serving as the *** optimization and cross-validation were utilized for model optimization and training based on a limited data set,resulting in higher predictive accuracy compared to traditional artificial neural network *** statistical analysis of the ANN and stacking models indicates that the stacking model exhibits superior performance on the test set,with a coefficient of determination value of 0.944,mean absolute percentage error of 2.51%,and root mean squared error of 27.64,surpassing that of the ANN *** statistical metrics demonstrate superiority over those obtained from the ANN *** results confirm that by integrating the base models,the stacking model exhibits superior predictive stability compared to individual base models alone,thereby providing a reliable assessment approach for predicting the mechanical properties of metal parts fabricated by the LPBF process.

关键词： machine learning laser powder bed fusion ensemble learning stacking algorithm additive manufacturing

Cooperative Target Fencing of Multiple Vehicles for a General Target with Connectivity Preservation and Collision Avoidance

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Journal of Systems Science & Complexity 2024年第1期37卷 136-151页

作者： PAN Zini CHEN Ben M department of mechanical and Automation engineering The Chinese University of Hong KongHong KongChina

In this paper,the authors study the cooperative target-fencing problem for n-dimensional systems and a target with a general *** using the velocity of the vehicles,a position feedback control law is proposed to fence the general target into the convex hull formed by the ***,the dynamics of each vehicle is described by a double-integrator *** potential functions are designed to guarantee connectivity preservation of the communication network and collision avoidance among the *** proposed approach can deal with a target whose trajectory is any twice continuously differentiable function of *** effectiveness of the result is verified by a numerical example.

关键词： Multi-agent systems networked systems target fencing