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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

Adaptive Robust Servo Control for Vertical Electric Stabilization System of Tank and Experimental Validation

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Defence Technology（防务技术） 2024年第1期31卷 326-342页

作者： Darui Lin Xiuye Wang Yimin Wang Guolai Yang school of mechanical engineering Nanjing University of Science and TechnologyNanjing210094China

A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is *** paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain ***,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the ***,the dynamical equation in the form of state space is established by designing the angular tracking ***,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of ***,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is *** feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental *** paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time.

关键词： Adaptive robust servo control Experimental validation Nonlinearity compensation System uncertainty Vertical electric stabilization system

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

Precision motion control for electro-hydraulic axis systems under unknown time-variant parameters and disturbances

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Chinese Journal of Aeronautics 2024年第1期37卷 463-471页

作者： Xiaowei YANG Yaowen GE Wenxiang DENG Jianyong YAO school of mechanical engineering Nanjing University of Science and TechnologyNanjing 210094China

This article focuses on asymptotic precision motion control for electro-hydraulic axis systems under unknown time-variant parameters,mismatched and matched *** from the traditional adaptive results that are applied to dispose of unknown constant parameters only,the unique feature is that an adaptive-gain nonlinear term is introduced into the control design to handle unknown time-variant *** both mismatched and matched disturbances existing in electro-hydraulic axis systems can also be addressed in this *** skillful integration of the backstepping technique and the adaptive control,a synthesized controller framework is successfully developed for electro-hydraulic axis systems,in which the coupled interaction between parameter estimation and disturbance estimation is ***,this designed controller has the capacity of low-computation costs and simpler parameter tuning when compared to the other ones that integrate the adaptive control and observer/estimator-based technique to dividually handle parameter uncertainties and ***,a nonlinear filter is designed to eliminate the“explosion of complexity”issue existing in the classical back-stepping *** stability analysis uncovers that all the closed-loop signals are bounded and the asymptotic tracking performance is also ***,contrastive experiment results validate the superiority of the developed method as well.

关键词： Adaptive control Asymptotic convergence Electro-hydraulic axis system Precision motion control Unknown time-variant parameters and disturbances

Numerical Investigation of Zigzag Bending-Angle Channel Effects on Thermal Hydraulic Performance of Printed Circuit Heat Exchanger

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Journal of Thermal Science 2024年第1期33卷 56-69页

作者： Nyein Nyein AYE Withun HEMSUWAN Pichitra UANGPAIROJ Chalothorn THUMTHAE school of mechanical engineering Suranaree University of TechnologyNakhon Ratchasima 30000Thailand

This study investigated the effects of zigzag-flow channel bending angle in printed circuit heat exchangers(PCHEs) using a computational fluid dynamics method with ANSYS-FLUENT *** three-dimensional model of PCHE with a 15° curved,zigzag channel was conducted for preliminary *** comparisons between the CFD simulation results and the experimental data showed good agreement with some discrepancies in the heat transfer and pressure drop *** addition,different bending angle configurations(0°,3° to 30°) of zigzag channels were analyzed to obtain better thermal-hydraulic performance of the zigzag channel PCHE under different inlet mass flow *** criteria of heat transfer and frictional factor were applied to evaluate the thermal-hydraulic performance of the *** results showed that the 6° and 9°bending channel provided good thermal-hydraulic *** correlations were developed using the 6°and 9° bending channel angles in PCHE designs to predict the Nusselt number and friction factor.

关键词： printed circuit heat exchanger zigzag channel angle three-dimensional model thermal-hydraulic performance

Nonlinear robust adaptive control for bidirectional stabilization system of all-electric tank with unknown actuator backlash compensation and disturbance estimation

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Defence Technology（防务技术） 2024年第2期32卷 144-158页

作者： Shusen Yuan Wenxiang Deng Jianyong Yao Guolai Yang school of mechanical engineering Nanjing University of Science and TechnologyNanjing210094China

Since backlash nonlinearity is inevitably existing in actuators for bidirectional stabilization system of allelectric tank,it behaves more drastically in high maneuvering *** this work,the accurate tracking control for bidirectional stabilization system of moving all-electric tank with actuator backlash and unmodeled disturbance is *** utilizing the smooth adaptive backlash inverse model,a nonlinear robust adaptive feedback control scheme is *** unknown parameters and unmodelled disturbance are addressed separately through the derived parametric adaptive function and the continuous nonlinear robust *** the unknown backlash parameters are updated via adaptive function and the backlash effect can be suppressed successfully by inverse operation,which ensures the system ***,the system disturbance in the high maneuverable environment can be estimated with the constructed adaptive law online improving the engineering ***,Lyapunov-based analysis proves that the developed controller can ensure the tracking error asymptotically converges to zero even with unmodeled disturbance and unknown actuator *** co-simulations and experiments illustrate the advantages of the proposed approach.

关键词： Bidirectional stabilization system Robust control Adaptive control Backlash inverse Disturbance estimation

Nonlinear wave dispersion in monoatomic chains with lumped and distributed masses:discrete and continuum models

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 633-648页

作者： E.GHAVANLOO S.EL-BORGI school of mechanical engineering Shiraz UniversityShiraz 71963-16548Iran mechanical engineering Program Texas A&M University at QatarDoha 23874Qatar

The main objective of this paper is to investigate the influence of inertia of nonlinear springs on the dispersion behavior of discrete monoatomic chains with lumped and distributed *** developed model can represent the wave propagation problem in a non-homogeneous material consisting of heavy inclusions embedded in a *** inclusions are idealized by lumped masses,and the matrix between adjacent inclusions is modeled by a nonlinear spring with distributed ***,the model is capable of depicting the wave propagation in bi-material bars,wherein the first material is represented by a rigid particle and the second one is represented by a nonlinear spring with distributed *** discrete model of the nonlinear monoatomic chain with lumped and distributed masses is first considered,and a closed-form expression of the dispersion relation is obtained by the second-order Lindstedt-Poincare method(LPM).Next,a continuum model for the nonlinear monoatomic chain is derived directly from its discrete lattice model by a suitable continualization *** subsequent use of the second-order method of multiple scales(MMS)facilitates the derivation of the corresponding nonlinear dispersion relation in a closed *** novelties of the present study consist of(i)considering the inertia of nonlinear springs on the dispersion behavior of the discrete mass-spring chains;(ii)developing the second-order LPM for the wave propagation in the discrete chains;and(iii)deriving a continuum model for the nonlinear monoatomic chains with lumped and distributed ***,a parametric study is conducted to examine the effects of the design parameters and the distributed spring mass on the nonlinear dispersion relations and phase velocities obtained from both the discrete and continuum *** parameters include the ratio of the spring mass to the lumped mass,the nonlinear stiffness coefficient of the spring,and the wave amplitude.

关键词： nonlinear mass-spring chain discrete model continuum model LindstedtPoincare method(LPM) method of multiple scales(MMS) dispersion phase velocity

A novel domain decomposition-based model for efficient dynamic predictions of large composite machine tools

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Science China(Technological Sciences) 2024年第6期67卷 1765-1782页

作者： YU YangBo JI Yu Lei CHEN YanRen XU Kun BI QingZhen State Key Laboratory of mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China

We propose a large combined moving component composed of carbon fiber reinforced polymer(CFRP)laminates for making lightweight machine tools with high dynamic *** accurate dynamic prediction of composite machine tools is essential for the new generation machine *** paper aims to address two challenges in numerical dynamic modeling and the design of composite machine tools to enhance development efficiency.(1)Anisotropic composite laminates,which form the composite machine tool,exhibit coupling in various *** propose the generalized continuity condition of the boundary to tackle this dynamic modeling challenge.(2)Composite machine tools feature numerous composite-metal coupled *** mechanical model correction of isotropic metals is performed to address their *** take the example of a five-axis gantry machine tool with composite moving parts,establish a dynamic model for efficient prediction,and verify it through simulation and *** proposed method yields remarkable results,with an average relative error of only 3.85%in modal frequency prediction and a staggering 99.7%reduction in solution time compared to finite element *** further discuss the dynamic performance of the machine tool under varied stacking angles and layer numbers of the composite machine *** propose general design criteria for composite machine tools to consider the modal frequency and manufacturing cost of machine tools.

关键词： machine tool dynamics carbon fiber reinforced polymer composite laminates

Key Technologies and Prospects for Electric vehicles Within Emerging Power Systems: Insights from Five Aspects

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 439-447页

作者： Yalun Li Minggao Ouyang C.C.Chan Xueliang Sun Yonghua Song Wei Cai Yilin Xie Yuqiong Mao Department of Electrical engineering and School of Vehicle and MobilityTsinghua UniversityBeijing 100084China school of vehicle and Mobility Tsinghua UniversityBeijing 100084China Department of Electrical and Electronic engineering The University of Hong KongHong Kong 999077China Department of mechanical and Materials engineering University of Western OntarioLondonON N6A 3K7Canada State Key Laboratory of Internet of Things for Smart City University of MacaoTaipaMacao 999078China Department of Electrical engineering Tsinghua UniversityBeijing 100084China school of Electrical and Electronic engineering Harbin University of Science and TechnologyHarbin 150080China

The energy revolution requires coordination in energy consumption, supply, storage and institutional *** energy generation technologies, along with their associated costs, are already fully equipped for large-scale ***, energy storage remains a bottleneck, and solutions areneeded through the use of electric vehicles, which traditionallyplay the role of energy consumption in power systems. Toclarify the key technologies and institutions that support EVsas terminals for energy use, storage, and feedback, the CSEEJPES forum assembled renowned experts and scholars in relevantfields to deliver keynote reports and engage in discussions ontopics such as vehicle–grid integration technology, advancedsolid-state battery technology, high-performance electric motortechnology, and institutional innovation in the industry *** experts also provided prospects for energy storage andutilization technologies capable of decarbonizing new powersystems.

关键词： Electric vehicles engineering philosophy highpower density motor new power system solid state batteries vehicle grid integration.