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Spectrum analysis of interval process model and its application in uncertain vibration analysis

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Science China Technological Sciences 2024年第8期67卷 2549-2564页

作者： LI JinWu JIANG Chao NI BingYu State Key Laboratory of advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University

In recent years, the authors have extended the traditional interval method into the time dimension to develop a new mathematical tool called the “interval process model” for quantifying time-varying or dynamic uncertainties. This model employs upper and lower bounds instead of precise probability distributions to quantify uncertainty in a parameter at any given time point. It is anticipated to complement the conventional stochastic process model in the coming years owing to its relatively low dependence on experimental samples and ease of understanding for engineers. Building on our previous work, this paper proposes a spectrum analysis method to describe the frequency domain characteristics of an interval process, further strengthening the theoretical foundation of the interval process model and enhancing its applicability for complex engineering problems. In this approach, we first define the zero midpoint function interval process and its auto/cross-power spectral density(PSD) functions. We also deduce the relationship between the auto-PSD function and the auto-covariance function of the stationary zero midpoint function interval process. Next, the auto/cross-PSD function matrices of a general interval process are defined, followed by the introduction of the concepts of PSD function matrix and cross-PSD function matrix for interval process vectors. The spectrum analysis method is then applied to random vibration problems, leading to the creation of a spectrum-analysis-based interval vibration analysis method that determines the PSD function for the system displacement response under stationary interval process excitations. Finally, the effectiveness of the formulated spectrum-analysis-based interval vibration analysis approach is verified through two numerical examples.

关键词： interval process spectrum analysis power spectral density (PSD) time-varying uncertainty uncertain vibration analysis

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Unified method for typical gear failure modeling and stiffness calculation based on the matrix equation

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Frontiers of mechanical engineering 2024年第3期19卷 93-114页

作者： Fanshan MENG Xin ZHANG Heng XIA Jiaxu WANG School of mechanical engineering Southwest Jiaotong UniversityChengdu 610031China State Key Laboratory of mechanical Transmissions for advanced Equipment Chongqing UniversityChongqing 400044China

The failure types in gear systems vary,with typical ones mainly including pitting,cracking,wear,and broken *** modeling and stiffness calculation methods have been developed for various gear failure types.A unified method for typical gear failure modeling and stiffness calculation is introduced in this study by considering the deviations in the time-varying meshing stiffness(TVMS)of faulty gears resulting from the use of different ***,a gear tooth is discretized into a large number of microelements expressed with a matrix,and unified models of typical gear failures are built by adjusting the values of the matrix *** values and positions of the microelements in the tooth failure model matrix have the same physical meaning as the parameter variables in the potential energy method(PEM),so the matrix-based failure model can be perfectly matched with ***,a unified method for TVMS is *** of healthy and faulty gears with pitting,wear,crack,and broken tooth is performed with the matrix equation,and the corresponding TVMS values are calculated by incorporating the matrix models with *** the basis of the results,the mechanism of typical fault types that affect TVMS is analyzed,and the conclusions are verified through the finite element *** developed unified method is a promising technique for studying the dynamic response characteristics of gear systems with different failure types because of its superiority in eliminating stiffness deviations.

关键词： gears matrix equation failure modeling TVMS calculation unified method

Deep neural network-enabled battery open-circuit voltage estimation based on partial charging data

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Journal of Energy Chemistry 2024年第3期90卷 120-132,I0005页

作者： Ziyou Zhou Yonggang Liu Chengming Zhang Weixiang Shen Rui Xiong State Key Laboratory of mechanical Transmission for advanced Equipment&College of mechanical and Vehicle engineering Chongqing UniversityChongqing 400000China Department of Vehicle engineering School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China Department of Electrical engineering Harbin Institute of TechnologyHarbin 150000HeilongjiangChina School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyHawthornVictoria 3122Australia

Battery management systems(BMSs) play a vital role in ensuring efficient and reliable operations of lithium-ion *** main function of the BMSs is to estimate battery states and diagnose battery health using battery open-circuit voltage(OCV).However,acquiring the complete OCV data online can be a challenging endeavor due to the time-consuming measurement process or the need for specific operating conditions required by OCV estimation *** addressing these concerns,this study introduces a deep neural network-combined framework for accurate and robust OCV estimation,utilizing partial daily charging *** incorporate a generative deep learning model to extract aging-related features from data and generate high-fidelity OCV *** analysis is employed to identify the optimal partial charging data,optimizing the OCV estimation precision while preserving exceptional *** validation results,using data from nickel-cobalt-magnesium(NCM) batteries,illustrate the accurate estimation of the complete OCV-capacity curve,with an average root mean square errors(RMSE) of less than 3 *** this level of precision for OCV estimation requires only around 50 s collection of partial charging *** validations on diverse battery types operating under various conditions confirm the effectiveness of our proposed *** cases of precise health diagnosis based on OCV highlight the significance of conducting online OCV *** method provides a flexible approach to achieve complete OCV estimation and holds promise for generalization to other tasks in BMSs.

关键词： Lithium-ion battery Open-circuit voltage Health diagnosis Deep learning

Dynamic modeling and RBF neural network compensation control for space flexible manipulator with an underactuated hand

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Chinese Journal of Aeronautics 2024年第3期37卷 417-439页

作者： Dongyang SHANG Xiaopeng LI Meng YIN Fanjie LI School of mechanical engineering and Automation Northeastern UniversityShenyang 110819China Shenzhen Institute of advanced Technology Chinese Academy of SciencesShenzhen 518055China

In space operation,flexible manipulators and gripper mechanisms have been widely used because of light weight and ***,the vibration caused by slender structures in manipulators and the parameter perturbation caused by the uncertainty derived from grasping mass variation cannot be *** existence of vibration and parameter perturbation makes the rotation control of flexible manipulators difficult,which seriously affects the operation accuracy of ***’s more,the complex dynamic coupling brings great challenges to the dynamics modeling and vibration *** solve this problem,this paper takes the space flexible manipulator with an underactuated hand(SFMUH)as the research *** dynamics model considering flexibility,multiple nonlinear elements and disturbance torque is established by the assumed modal method(AMM)and Hamilton’s principle.A dynamic modeling simplification method is proposed by analyzing the nonlinear ***’s more,a sliding mode control(SMC)method combined with the radial basis function(RBF)neural network compensation is ***,the control law is designed using a saturation function in the control method to weaken the chatter *** the help of neural networks to identify the uncertainty composition in the SFMUH,the tracking accuracy is *** results of ground control experiments verify the advantages of the control method for vibration suppression of the SFMUH.

关键词： Space flexible manipulator RBF neural network Underactuated hand Dynamic models Model simplification

Unveiling the size effect of nitrogen-doped carbon-supported copper-based catalysts on nitrate-to-ammonia electroreduction

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Nano Research 2024年第4期17卷 2438-2443页

作者： Ran Li Taotao Gao Wenxi Qiu Minghao Xie Zhaoyu Jin Panpan Li College of Materials Science and engineering Sichuan UniversityChengdu 610065China Institute for advanced Study Chengdu UniversityChengdu 610106China Materials Science and engineering program and Walker Department of mechanical engineering The University of Texas at AustinAustinTexas 78712USA Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China

The electrocatalytic nitrate reduction reaction(NitRR)represents a promising approach toward achieving economically and environmentally sustainable ***,it remains a challenge to regulate the size effect of electrocatalysts to optimize the catalytic activity and ammonia ***,the Cu-based catalysts were tailored at the atomic level to exhibit a size gradient ranging from single-atom catalysts(SACs,0.15–0.35 nm)to single-cluster catalysts(SCCs,1.0–2.8 nm)and nanoparticles(NPs,20–30 nm),with the aim of studying the size effect for the NO_(3)^(-)-to-NH_(3) reduction ***,the Cu SCCs exhibit enhanced metal–substrate and metal–metal interactions by taking advantageous features of Cu SACs and Cu ***,Cu SCCs achieve exceptional electrocatalytic performance for the NitRR with a maximum Faradaic efficiency of ca.96%NH_(3)and the largest yield rate of ca.1.99 mg·h^(-1)·cm^(-2) at-0.5 V *** hydrogen electrode(RHE).The theoretical calculation further reveals the size effect and coordination environment on the high catalytic activity and selectivity for the *** work provides a promising various size-controlled design strategy for aerogel-based catalysts effectively applied in various electrocatalytic reactions.

关键词： nitrate electroreduction ammonia electrosynthesis size effect single-cluster catalyst

Interface strengthening for thermal sprayed WC-10Co4Cr coating subjected to pulsed magnetic treatment

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Rare Metals 2024年第2期43卷 780-795页

作者： Cheng-Kai Qian Qu Liu Heng Wang Ke-Jian Li Zhi-Peng Cai Department of mechanical engineering Tsinghua UniversityBeijing100084China Tianjin Research Institute for advanced Equipment Tsinghua UniversityTianjin300304China State Key Laboratory of Tribology in advanced Equipment Tsinghua UniversityBeijing100084China

The reliability of the coated industry components demands ideal fatigue properties of the coating,and it is mainly determined by the performance of the *** this study,pulsed magnetic treatment(PMT)was applied to the thermal sprayed WC-10Co4Cr coating,and the fatigue lifetime of the coated bolt increased by 219.82%under an imitation of the operating mode *** tests further proved that both the adhesion and cohesion strength were improved after PMT,and they benefit from the interface strengthening *** formation of coherent WC/Co interfaces was characterized by in-situ transmission electron microscopy(TEM),and the molecular dynamic simulations indicate that the work of separation of these interfaces is much higher than the original disordered *** stress was relaxed and distributed more homogeneously after PMT,and it mainly contributes to the coating/substrate *** work provides a new post-treatment method focusing on the interfaces in the WC-based coating and gives insight into its mechanism so that it is hopeful to be applied to other kinds of coatings.

关键词： Cemented carbide coating Pulsed magnetic treatment Interface strengthening Fatigue properties Adhesion strength

Cyclic Pulsating Pressure Enhanced Segregating Structuration of Ultra-High Molecular Weight Polyethylene/Graphene Composites as High-performance Light-Weight EMI Shields

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Chinese Journal of Polymer Science 2024年第7期42卷 958-967,I0008页

作者： Yun-Zhi Huang Xiao-Xiao Liu Lan-Wei Li Guang-Ming Huang Zhao-Xia Huang Jin-Ping Qu National engineering Research Center of Novel Equipment for Polymer Processing Key Laboratory of Polymer Processing EngineeringMinistry of EducationGuangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced ManufacturingSchool of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhou 510641China School of advanced Manufacturing Technology Guangdong Mechanical&Electrical PolytechnicGuangzhou 510550China

Currently,the enhancement in electromagnetic interference(EMI)performance of polymeric composite generally relies on either improving electrical conductivity(σ)for stronger electromagnetic(EM)reflections or tailoring structure for higher EM ***,we proposed a novel technique called cyclic pulsating pressure enhanced segregating structuration(CPP-SS),which can reinforce these two factors *** structural information was supplied by optical microscopy(OM)and scanning electron microscopy(SEM),both of which confirmed the formation and evolution of segregate structured ultra-high molecular weight polyethylene(UHMWPE)/graphene ***,the result showed that CPP-SS can significantly improve theσof ***,advanced specific EMI shielding efficiency of 31.1 d B/mm was achieved for UHMWPE/graphene composite at 1-mm thickness and a low graphene loading of 5 wt%.Meanwhile,it also confirmed that the intrinsic disadvantage of poor mechanical properties of conventional segregated structure composites can be *** work is believed to provide a fundamental understanding of the structural and performance evolutions of segregated structured composites prepared under CPPSS,and to bring us a simple and efficient approach for fabricating high-performance,strong and light-weight polymeric EMI shields.

关键词： Cyclic pulsating pressure Segregated structure Ultra-high molecular weight polyethylene Graphene Electromagnetic interface

Templated synthesis of transition metal phosphide electrocatalysts for oxygen and hydrogen evolution reactions

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Journal of Energy Chemistry 2024年第2期89卷 646-669,I0014页

作者： Rose Anne Acedera Alicia Theresse Dumlao DJ Donn Matienzo Maricor Divinagracia Julie Anne del Rosario Paraggua Po-Ya Abel Chuang Joey Ocon Laboratory of Electrochemical engineering(LEE) Department of Chemical EngineeringUniversity of the PhilippinesDilimanQuezon City 1101Philippines mechanical engineering University of CaliforniaMercedCA 95343USA Energy engineering program College of EngineeringUniversity of the PhilippinesDilimanQuezon City 1101Philippines

Transition metal phosphides(TMPs)have been regarded as alternative hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts owing to their comparable activity to those of noble metal-based *** have been produced in various morphologies,including hollow and porous nanostructures,which are features deemed desirable for electrocatalytic *** synthesis routes are often responsible for such *** paper reviews the latest advances and existing challenges in the synthesis of TMP-based OER and HER catalysts through templated methods.A comprehensive review of the structure-property-performance of TMP-based HER and OER catalysts prepared using different templates is *** discussion proceeds according to application,first by HER and further divided among the types of templates used-from hard templates,sacrificial templates,and soft templates to the emerging dynamic hydrogen bubble *** catalysts are then reviewed and grouped according to their ***,prospective research directions for the synthesis of hollow and porous TMP-based catalysts,such as improvements on both activity and stability of TMPs,design of environmentally benign templates and processes,and analysis of the reaction mechanism through advanced material characterization techniques and theoretical calculations,are suggested.

关键词： OER HER Transition metal phosphide Templated synthesis Electrocatalysts

Solvent-free carbon sphere nanofluids towards intelligent lubrication regulation

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Friction 2024年第1期12卷 95-109页

作者： Sheng ZHANG Wen LI Xiaoliang MA Xiaoqiang FAN Minhao ZHU Tribology Research Institute School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China Key Laboratory of advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China

By simply switching the electrical circuit installed on steel/steel contact,the tribological behaviors of nanofluids(NFs)can be regulated in real time,thereby achieving the desired performance of friction reduction and wear ***,solvent-free carbon spherical nanofluids(C-NFs)were successfully prepared for intelligent lubrication regulation.C-NFs with excellent lubrication performance can immediately reduce the coefficient of friction(COF)despite applying a weak electric potential(1.5 V).Moreover,polyethylene glycol 400(PEG400)containing 5.0 wt%C-NFs remained responsive to electrical stimulation under the intermittent voltage application with an average coefficient of friction(ACOF)reduction of 20.8%over *** intelligent lubrication regulation of C-NFs under an external electric field(EEF)mainly depends on the orderly arranged double-electric adsorption film of ion canopy-adsorbed carbon spheres(CSs).The intermittent electrical application can continuously reinforce the adsorption film and its durability for real-time controlling the sliding ***-stimulation-responsive intelligent lubricants provide a new technical support for realizing intelligent stepless control of devices.

关键词： solvent-free carbon spherical nanofluids(C-NFs) intelligent lubrication regulation lubrication performance adsorption film