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Effect of boundary conditions on shakedown analysis of heterogeneous materials

Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 39-68页

作者： Xiuchen GONG Yinghao NIE Gengdong CHENG Kai LI State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentInternational Research Center for Computational MechanicsDepartment of Engineering MechanicsDalian University of TechnologyDalian 116023Liaoning ProvinceChina

The determination of the ultimate load-bearing capacity of structures made of elastoplastic heterogeneous materials under varying loads is of great importance for engineering analysis and design. Therefore, it is necessary to accurately predict the shakedown domains of these materials. The static shakedown theorem, also known as Melan's theorem, is a fundamental method used to predict the shakedown domains of structures and materials. Within this method, a key aspect lies in the construction and application of an appropriate self-equilibrium stress field(SSF). In the structural shakedown analysis, the SSF is typically constructed by governing equations that satisfy no external force(NEF) boundary conditions. However, we discover that directly applying these governing equations is not suitable for the shakedown analysis of heterogeneous materials. Researchers must consider the requirements imposed by the Hill-Mandel condition for boundary conditions and the physical significance of representative volume elements(RVEs). This paper addresses this issue and demonstrates that the sizes of SSFs vary under different boundary conditions, such as uniform displacement boundary conditions(DBCs), uniform traction boundary conditions(TBCs), and periodic boundary conditions(PBCs). As a result, significant discrepancies arise in the predicted shakedown domain sizes of heterogeneous materials. Built on the demonstrated relationship between SSFs under different boundary conditions, this study explores the conservative relationships among different shakedown domains, and provides proof of the relationship between the elastic limit(EL) factors and the shakedown loading factors under the loading domain of two load vertices. By utilizing numerical examples, we highlight the conservatism present in certain results reported in the existing literature. Among the investigated boundary conditions, the obtained shakedown domain is the most conservative under ***, utilizing PBCs to

关键词： heterogeneous material self-equilibrium stress field(SSF) shakedown analysis effect of boundary conditions

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Null test for cosmic curvature using Gaussian process

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Chinese Physics C 2023年第5期47卷 259-270页

作者：武鹏举祁景钊张鑫 Key Laboratory ofCosmology and Astrophysics(Liaoning Province)&Department of Physics College of SciencesNortheastern UniversityShenyang 110819China Key Laboratory of Data Analytics and optimization for Smart Industry(Ministry of Education) Northeastern UniversityShenyang 110819China National Frontiers Science center for Industrial Intelligence and Systems optimization Northeastern UniversityShenyang 110819China

The cosmic curvature Ω_(K,0),which determines the spatial geometry of the universe,is an important parameter in modern *** deviation from Ω_(K,0)=0 would have a profound impact on the primordial inflation paradigm and fundamental *** this work,we adopt a cosmological model-independent method to test whether Ω_(K,0) deviates from *** use the Gaussian process to reconstruct the reduced Hubble parameter E(z)and the derivative of the distance D'(z)from observational data and then determine Ω_(K,0) with a null test *** cosmic chronometer(CC)Hubble data,baryon acoustic oscillation(BAO)Hubble data,and supernovae Pantheon sample are *** result is consistent with a spatially flat universe within the domain of reconstruction 01,it tends to favor a closed *** this sense,there is still a possibility for a closed *** also carry out the null test of the cosmic curvature at 0

关键词： cosmic curvature Gaussian process cosmological observations cosmological model-independent method null test

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Spherical Formation of Regular Tetrahedra 36

Spherical Formation of Regular Tetrahedra

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第36届中国控制会议

作者： Zhang Silun He Fenghua Yao Yu Hu Xiaoming optimization and Systems Theory Department of MathematicsKTH Royal Institute of Technology Control and Simulation center Harbin Institute of Technology

ISBN: (纸本)9781538629185

In this paper, we study the problem of tracking and encircling a moving target by agents in the 3-dimensional ***, a group of agents are driven to a regular tetrahedron formation on a spherical surface and simultaneously keep the center of this spherical formation coinciding with the target to be tracked. In the proposed method, to avoid the singularity caused by spherical parameterisations in control, we directly consider the spherical formation in space S2. Besides, the protocol proposed does not contain any information of the desired formation beforehand. Rather the constructed formation pattern is attributed to the properties of space S2 and the inter-agent topology.

关键词： Multi-agent systems formation control encircling control nonlinear feedback control

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Electrochemical response of MoS_(2) nanosheets/SiO_(2)-NH_(2) nanoparticles modified glassy carbon electrode to phenylacetic acid

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Rare Metals 2023年第12期42卷 4142-4152页

作者： Tian-Yao Qi Zhen-Yu Yuan Fan-Li Meng College of Information Science and Engineering Northeastern UniversityShenyang 110819China Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology Qinhuangdao 066004China National Frontiers Science center for Industrial Intelligence and Systems optimization Northeastern UniversityShenyang 110819China Key Laboratory of Data Analytics and optimization for Smart Industry(Northeastern University) Ministry of EducationShenyang 110819China

Phenylacetic acid(PAA)is a primary raw material for illegal Methamphetamine(MATM)synthesis under the strong precursor chemicals supervisions of safrole and ***,trace detection of PAA at ultra-low concentration is a strategic technique and an urgent issue in the field of drug *** this paper,trace determination of PAA at sub-nmol-L-1 concentration level is achieved by hydrogen bond adsorption and electrochemical catalysis through the prepared aminated SiO_(2)nanoparticles(SiO_(2)-NH_(2) NPs)and MoS_(2) nanosheets(NSs)modified glassy carbon electrode(GCE).The prepared MoS_(2) NS s/SiO_(2)-NH_(2) NPs modified electrode represents a detecting limit of 0.0989 nmol·L^(-1)and an obvious increasing linear range before the concentration increasement up to 60 nmol·L^(-1)in square wave voltammetry(SWV)responses of *** SWV response of the modified electrode to PAA in the concentration range within 100 nmol·L^(-1)is higher than phenol,acetic acid(HOAc)and benzoic Acid(BEN).This electrochemical method for trace detection of PAA in aqueous solution with desired performance provides a feasible scheme for the detection of other drugs and aromatic precursor chemicals.

关键词： Phenylacetic acid detection Modified electrode MoS_(2)nanosheet Square wave voltammetry

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Deterministic learning from control of nonlinear systems with disturbances

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Progress in Natural Science:Materials International 2009年第8期19卷 1011-1019页

作者： Guopeng Zhou a,b, Cong Wang a, a School of Automation and center for Control and optimization, South China University of Technology, Guangzhou 510640, China b College of Mathematics and Statistics, Xianning University, Xianning 437005, China [a]School of Automation and center for Control and optimization South China University of Technology Guangzhou 510640 China [b]College of Mathematics and Statistics Xianning University Xianning 437005 China

In this paper, we investigate deterministic learning in environments with disturbances. We will show that for a class of uncertain nonlinear systems with bounded disturbances, by using an appropriately designed adaptive neural controller, the disturbances are attenuated and the system output tracks a periodic orbit in finite time. As radial basis function (RBF) neural networks (NN) are employed, this leads to the satisfaction of a partial persistence of the excitation (PE) condition. By using the uniform complete observability (UCO) technique, it is analyzed that partial estimated NN weights will converge to a neighborhood of zero, with the size of the neighborhood depending on the amplitude of disturbances as well as on the control gains. Locally-accurate approximation of unknown system dynamics can still be achieved in the stable NN control process. The approximation error level is influenced by the amplitude of disturbances. The obtained knowledge of system dynamics can be reused in another control process towards stability and improved performance. Simulation studies are included to demonstrate the effectiveness of the approach.

关键词： Deterministic learning Adaptive NN control Disturbance Partial PE condition Uniform complete observability

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Finite-time control for a class of hybrid systems via quantized intermittent control

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Science China(Information Sciences) 2020年第9期63卷 140-155页

作者： Xiaolin XIONG Xinsong YANG Jinde CAO Rongqiang TANG Cunjin College Guangdong Ocean University School of Mathematical Sciences Chongqing Normal University Key Laboratory of optimization and Control Ministry of Education School of Mathematics and Research Center for Complex Systems and Network SciencesSoutheast University

This paper considers the finite-time drive-response synchronization of stochastic nonlinear systems consisting of continuous-time and discrete-time subsystems. To save communication resources and reduce control cost, quantized controllers, which only work on continuous-time intervals, are designed. Owing to the hybrid characteristics of continuous-and discrete-time subsystems, existing finite-time stability theorems are not applicable. By developing novel analytical techniques, three criteria are derived to guarantee the finite-time synchronization. Moreover, the settling time is explicitly estimated. It is shown that the settling time is dependent not only on the control gains and systems’ initial conditions, but also on the control width and uncontrolled width. Numerical examples demonstrate the effectiveness of the theoretical analysis.

关键词： hybrid system finite-time synchronization quantized intermittent control stochastic perturbation

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COOPERATIVE SHIFT ESTIMATION OF TARGET TRAJECTORY USING CLUSTERED SENSORS

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Journal of Systems Science & Complexity 2014年第3期27卷 413-429页

作者： HU Jiangping HU Xiaoming SHEN Tielong School of Automation Engineering University of Electronic Science and Technology of China optimization and Systems Theory and ACCESS Linnaeus center Royal Institute of TechnologyStockholmSweden Department of Engineering and Applied Sciences Sophia UniversityTokyoJapan

In this paper,a mathematical model for target tracking using nonlinear scalar range sensors is formulated first.A time-shift sensor scheduling strategy is addressed on the basis of a k-barrier coverage protocol and all the sensors are divided into two classes of clusters,active cluster,and submissive cluster,for *** two types of time-shift nonlinear filters are proposed for both active and submissive clusters to estimate the trajectory of the moving target with disturbed *** stochastic stability of the two filters is ***,some numerical simulations are given to demonstrate the effectiveness of the new filters with a comparison of EKF.

关键词： Cluster sensor network target tracking time-shift estimation

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Time-Varying Formation Tracking Control of Heterogeneous Multi-Agent Systems With Intermittent Communications and Directed Switching Networks

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IEEE/CAA Journal of Automatica Sinica 2025年第1期 294-296页

作者： Yuhan Wang Zhuping Wang Hao Zhang Huaicheng Yan the Shanghai Research Institute for Intelligent Autonomous Systems Tongji University the National Key Laboratory of Autonomous Intelligent Unmanned Systems the Frontiers Science center for Intelligent Autonomous System of Ministry of Education the College of Electronic and Information Engineering the Department of Control Science and Engineering Tongji University the Key Laboratory of Advanced Control and optimization for Chemical Processes of Ministry of Education the School of Information Science and Engineering East China University of Science and Technology

Dear Editor,This letter is concerned with the problem of time-varying formation tracking for heterogeneous multi-agent systems(MASs) under directed switching networks. For this purpose, our first step is to present some sufficient conditions for the exponential stability of a particular category of switched systems.

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L_(p) Quasi Norm State Estimator for Power Systems

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Journal of Modern Power Systems and Clean Energy 2022年第4期10卷 871-882页

作者： Zhongliang Lyu Hua Wei Xiaoqing Bai Daiyu Xie Le Zhang Peijie Li School of Electrical Engineering Guangxi UniversityNanningChinaand they are also with the Guangxi Key Laboratory of Power System Optimization and Energy TechnologyGuangxi UniversityNanningChin Power Dispatching Control center of Guangxi Power Grid NanningChina

This paper proposes an L_(p)(0 详细信息

This paper proposes an L_(p)(0

关键词： Power system bad data quasi norm estimator robustness state estimation

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PARALLEL SIMULTANEOUS STABILIZATION OF A SET OF PORT-CONTROLLED HAMILTONIAN SYSTEMS SUBJECT TO ACTUATOR SATURATION

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Journal of Systems Science & Complexity 2011年第1期24卷 120-139页

作者： Airong WEI Yuzhen WANG Xiaoming HU School of Control Science and Engineering Shandong University Jinan 250061 ChinaOptimization and Systems Theory Royal Institute of Technology SE-10044 Stockholm Sweden School of Control Science and Engineering Shandong University Jinan 250061 China optimization and Systems Theory Royal Institute of Technology SE-100 44 Stockholm Sweden ACCESS Linnaeus center Royal Institute of Technology SE-100 44 Stockholm Sweden

This paper investigates parallel simultaneous stabilization （PSS） of a set of multi-input nonlinear Port-Controlled Hamiltonian （PCH） systems subject to actuator saturation （AS）, and proposes a number of results on the design of PSS controllers for the PCH systems with AS. Firstly, the case of two PCH systems with AS is studied. Exploring the special property of the saturation nonlinearity and the structural properties of dissipative Hamiltonian system, the two systems are combined to generate an augmented PCH system, with which some results on the control design are then obtained. When there are external disturbances in the two systems, a robust PSS controller is designed for the systems. Secondly, the case of more than two PCH systems with AS is investigated, and several new results are proposed for the PSS problem. Finally, two illustrative examples are presented to show that the stabilization controllers obtained in this paper work very well.

关键词： Actuator saturation PCH system robust parallel simultaneous stabilization

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