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A six-variable quasi-3D isogeometric approach for free vibration of functionally graded graphene origami-enabled auxetic metamaterial plates submerged in a fluid medium

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 157-176页

作者： Wei CHEN Zhihong TANG Yufen LIAO Linxin PENG college of Civil engineering University of South China college of Civil engineering and architecture Guangxi University Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education Guangxi University

This paper presents, for the first time, an effective numerical approach based on the isogeometric analysis(IGA) and the six-variable quasi-three dimensional(3D)higher-order shear deformation theory(HSDT) to study the free vibration characteristics of functionally-graded(FG) graphene origami(GOri)-enabled auxetic metamaterial(GOEAM) plates submerged in a fluid medium. The plate theory incorporates the thickness stretching and the effects of transverse shear deformation without using any shear correction factors. The velocity potential function and Bernoulli's equation are used to derive the hydrodynamic pressure acting on the plate surface. Both horizontally and vertically immersed plate configurations are considered here in the form of inertia *** plates are composed of multilayer GOEAMs, with the GOri content varying through the plate's thickness in a layer-wise manner. This design results in graded auxetic *** material properties are evaluated by mixing rules and a genetic programming(GP)-assisted micromechanical model. The governing equations of motion for the FG-GOEAM plates immersed in a fluid medium are derived by Hamilton's principle. After validating the convergence and accuracy of the present model, a comprehensive parametric study is carried out to examine the effects of the GOri content, GOri distribution pattern, GOri folding degree, fluid level, immersed depth, and geometric parameter on the natural frequencies of the FG-GOEAM plates. The results show that the natural frequencies for the four GOri distribution patterns increase with the increase in the layer number when the lay number is fewer than 10, and then stabilize after the layer number reaches ***, in general, the natural frequency of the FG-GOEAM plate in a vacuum or fluid increases when the GOri content increases, while decreases when the GOri folding degree increases. Some additional findings related to the numerical results are presented in the conclusions. It is belie

关键词： free vibration functionally-graded (FG) graphene origami (GOri)-enabled auxetic metamaterial (GOEAM) plate hydrodynamic pressure isogeometric analysis (IGA) O321 quasi-three dimensional (3D) higher-order shear deformation theory (HSDT)

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Experimental study on failure precursory characteristics and moisture content effect of pre-cracked rocks under graded cyclic loading and unloading

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International Journal of Mining Science and Technology 2025年第2期35卷 249-264页

作者： Wei Zhang Dongxiao Zhang Weiyao Guo Baoliang Zhang School of architecture and engineering Liaocheng UniversityLiaocheng 252000China college of Energy and Mining engineering Shandong University of Science and TechnologyQingdao 266590China

It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock *** on digital speckle correlation(DSCM),acoustic emission(AE)and electromagnetic radiation(EMR),uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry,natural and saturated water content,to explore the fracture propagation,failure precursor characteristics and damage response mechanism under the influence of water content *** results show that with the increase of water content,the peak stress and crack initiation stress decrease gradually,and the decreases are 15.28%-21.11%and 17.64%-23.04%,*** peak strain and crack initiation strain increase gradually,and the increases are 19.85%-44.53%and 19.15%-41.94%,*** precracked rock with different water content is mainly characterized by tensile failure at different loading ***,with the increase of water content,the proportion of shear cracks gradually increases,while acoustic emission events gradually decrease,the dissipative energy and energy storage limits of the rock under peak load gradually decrease,and the charge signal increases significantly,which is because the lubrication effect of water reduces the friction coefficient between crack surfaces.

关键词： Damage mechanisms Pre-cracked rocks Crack propagation Water-rock interaction Graded cyclic loading and unloading

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An Online Exploratory Maximum Likelihood Estimation Approach to Adaptive Kalman Filtering

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IEEE/CAA Journal of Automatica Sinica 2025年第1期12卷 228-254页

作者： Jiajun Cheng Haonan Chen Zhirui Xue Yulong Huang Yonggang Zhang the college of Intelligent Systems Science and engineering Harbin Engineering University the engineering Research Center of Navigation Instruments Ministry of Education the college of Intelligent Systems Science and engineering the college of Future Technology Harbin Engineering University IEEE

Over the past few decades, numerous adaptive Kalman filters(AKFs) have been proposed. However, achieving online estimation with both high estimation accuracy and fast convergence speed is challenging, especially when both the process noise and measurement noise covariance matrices are relatively inaccurate. Maximum likelihood estimation(MLE) possesses the potential to achieve this goal, since its theoretical accuracy is guaranteed by asymptotic optimality and the convergence speed is fast due to weak dependence on accurate state ***, the maximum likelihood cost function is so intricate that the existing MLE methods can only simply ignore all historical measurement information to achieve online estimation,which cannot adequately realize the potential of MLE. In order to design online MLE-based AKFs with high estimation accuracy and fast convergence speed, an online exploratory MLE approach is proposed, based on which a mini-batch coordinate descent noise covariance matrix estimation framework is developed. In this framework, the maximum likelihood cost function is simplified for online estimation with fewer and simpler terms which are selected in a mini-batch and calculated with a backtracking method. This maximum likelihood cost function is sidestepped and solved by exploring possible estimated noise covariance matrices adaptively while the historical measurement information is adequately utilized. Furthermore, four specific algorithms are derived under this framework to meet different practical requirements in terms of convergence speed, estimation accuracy,and calculation load. Abundant simulations and experiments are carried out to verify the validity and superiority of the proposed algorithms as compared with existing state-of-the-art AKFs.

关键词： Adaptive Kalman filtering coordinate descent maximum likelihood estimation mini-batch optimization unknown noise covariance matrix

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Characterization of combined blast-and fragments-induced synergetic damage in polyurea coated liquid-filled container

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Defence Technology(防务技术) 2025年第1期43卷 201-224页

作者： Chen Tao Chong Ji Xin Wang Juan Gu Yuting Wang Changxiao Zhao college of Field engineering Army Engineering University of PLANanjing210007China college of Defense engineering Army Engineering University of PLANanjing211101China

Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other *** an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves and *** explore the protective effect of polyurea elastomer on LFC,the damage characteristics of polyurea coated liquid-filled container(PLFC)under the combined loading of blast shock wave and fragments were studied *** microstructure of the polyurea layer was observed by scanning electron microscopy,and the fracture and self-healing phenomena were *** simulation approach was used to explain the combined blast-and fragments-induced on the PLFC in ***,the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively *** showed that the polyurea reduces the perforation rate of the fragment to the LFC,and the self-healing phenomenon could also reduce the liquid loss rate inside the *** polyurea reduces the degree of depression in the center of the LFC,resulting in a decrease in the distance between adjacent fragments penetrating the LFC,and an increase in the probability of transfixion and fracture between *** the close-in blast,the detonation shock wave reached the LFC before the *** does not all have an enhanced effect on the protection of *** presence of internal water enhances the anti-blast performance of the container,and the hydrodynamic ram(HRAM)formed by the fragment impacting the water aggravated the plastic deformation of the *** combined action has an enhancement effect on the deformation of the *** depth of the container depression was 27%higher than that of the blast shock wave alone;thus,it cannot be simply summarized as linear superposition.

关键词： Polyurea Prefabricated fragment Liquid-filled container Hydrodynamic ram Cumulative effect

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Effect of a Carbon Fibre-steel Fibre-graphite Conductive Filler on the Electrothermal Properties of Cementitious Materials

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 141-151页

作者： FAN Yanan WEI Hong ZHENG Hongyong DU Hongxiu Department of architecture and Environmental engineering Taiyuan UniversityTaiyuan 030032China college of Civil engineering Taiyuan University of TechnologyTaiyuan 030032China

Carbon fibre,steel fibre and graphite were used as conductive fillers to prepare cementitious materials with excellent electrothermal *** electrically conductive cementitious materials with different volume dosages were analysed through compressive and flexural strength,electrochemical impedance spectroscopy and temperature rise *** equivalent circuit model was established to study the electrically conductive heat generation mechanism in the electrically conductive cementitious *** results indicate that the mechanical properties of cementitious composite materials with a ternary conductive phase are better than those of pristine cementitious materials because the fibrous filler improves their mechanical ***,the incorporation of graphite in the material reduces its *** fibrous and point-like conductive phase materials into the cementitious material enhances the overall conductive pathway and considerably reduces the electrical resistance of the cementitious material,enhancing its conductive *** volume ratios of carbon fibre,steel fibre and graphite that achieve an optimal complex doping in the cementitious material were 0.35%,0.6%and 6%,*** was determined using the mutation point of each circuit element parameter as the percolation *** addition,at a certain safety voltage,there is a uniform change between the internal and surface temperatures of the conductive cementitious material,and the heating effect in this materialis is considerably better than that in the pristine cementitious material.

关键词： cementitious composites conductive fillers electrothermal properties electrochemical impedance spectroscopy

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Vibration safety assessment and parameter analysis of buried oil pipelines based on vibration isolation holes under strong surface impact

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Earthquake engineering and engineering Vibration 2025年第1期24卷 69-82页

作者： Wang Guobo Mei Hua Wang Jianning He Wei Yin Yao Zhai Yuxin Zuo Pengfei college of Civil engineering and architecture Wenzhou UniversityWenzhou 325035China Zhejiang engineering Research Center of Disaster Prevention and Mitigation for Coastal Soft Soil Foundation WenZhou 325035China China National Machinery Industry Co. Ltd.Beijing 100080China Faculty of engineering China University of GeosciencesWuhan 430074China China Railway Construction Group Co. Ltd.Beijing 100072China School of Civil engineering and architecture Wuhan University of TechnologyWuhan 430070China

Strong surface impact will produce strong vibration,which will pose a threat to the safety of nearby buried pipelines and other important lifeline *** on the verified numerical method,a comprehensive numerical parameter analysis is conducted on the key influencing factors of the vibration isolation hole(VIH),which include hole diameter,hole net spacing,hole depth,hole number,hole arrangement,and soil *** results indicate that a smaller ratio of net spacing to hole diameter,the deeper the hole,the multi-row hole,the hole adoption of staggered arrangements,and better site soil conditions can enhance the efficiency of the VIH *** average maximum vibration reduction efficiency within the vibration isolation area can reach 42.2%.The vibration safety of adjacent oil pipelines during a dynamic compaction projection was evaluated according to existing standards,and the measurement of the VIH was recommended to reduce excessive *** single-row vibration isolation scheme and three-row staggered arrangement with the same hole parameters are suggested according to different *** research findings can serve as a reference for the vibration safety analysis,assessment,and control of adjacent underground facilities under the influence of strong surface impact loads.

关键词： vibration isolation hole buried oil pipeline strong surface impact vibration velocity vibration safety assessment

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Dynamic Event-Triggered Active Disturbance Rejection Formation Control for Constrained Underactuated AUVs

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IEEE/CAA Journal of Automatica Sinica 2025年第2期12卷 460-462页

作者： Zhiguang Feng Sibo Yao IEEE the college of Intelligent Systems Science and engineering Harbin Engineering University

Dear Editor,This letter addresses the formation control problem for constrained underactuated autonomous underwater vehicles (AUVs). The feasibility condition of the virtual control law is eliminated by introducing a nonlinear state dependence function (NSDF) that transforms the state of each AUV in the formation.

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Thermal fracture analysis of two collinear cracks in a functionally graded medium based on the three-phase-lag model

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Applied Mathematics and Mechanics(English Edition) 2025年第3期46卷 501-520页

作者： Zhangna XUE Huameng WANG Jianlin LIU Minjie WEN Z.T.CHEN college of Pipeline and Civil engineering China University of Petroleum(East China) School of Civil engineering and architecture Zhejiang Sci-Tech University Department of Mechanical engineering University of Alberta

The three-phase-lag(TPL) heat conduction model is an accurate representation of the actual heat transfer process. It would be interesting to investigate how the TPL model affects the thermal fracture behavior when there are defects existing in the medium. This paper aims to analyze the thermoelastic responses of two collinear cracks within a functionally graded half-space under thermal loadings by means of the TPL model. The thermoelastic problem is transformed into a series of singular integral equations using the integral transformation methods. The transient temperature and stress intensity factors(SIFs) are obtained through the application of Chebyshev *** effects of crack spacing and non-homogeneous parameters on the transient thermoelastic responses are presented, and the results of the TPL model are compared with those of the Fourier model, Cattaneo and Vernotte(CV) model, and dual-phase-lag(DPL)model. It is shown that crack spacing and non-homogeneous parameters have important effects on the thermoelastic responses, and the fluctuation phenomenon under the TPL model is the most pronounced due to the existence of the thermal displacement lag term.

关键词： Chebyshev polynomials

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Comparative Evaluation and Performance Analysis of Heat Exchangers Featured with Peened Surface

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Journal of Thermal Science 2025年第1期34卷 50-61页

作者： DINESHBABU Chinnadurai SHIVA SANKARAN Nallasamy VENKATESH RAJAKrishnan VENKATESH Rathinavelu Department of Mechanical engineering Kongunadu College of Engineering and TechnologyTamil Nadu-621215India Department of Mechanical engineering Selvam College of TechnologyNamakkalTamil Nadu-637003India Department of Mechanical engineering Sona College of TechnologySalemTamil Nadu-636005India Department of Mechanical engineering Saveetha School of EngineeringSaveetha Institute of Medical and Technical Sciences(SIMATS)Saveetha UniversityChennai 602105TamilnaduIndia

Heat exchangers have the potential for various engineering applications,and their performance is enriched by surface *** proposed system enriches the heat exchanger's performance by adapting a peened stainless steel(SS)surface blasted with copper,grinding,sand,and *** influences peened SS surface modified with a copper blast,grinding,sandblast,and iron blast on the surface morphology of shell and tube heat exchanger surface(STHE)is analyzed via tungsten heated cathode electron gun featured scanning electron microscope and observed coarse grain *** SS surface featured STHE performance is experimentally evaluated by different flow rates(30,60,90,and 120 L/min)underwater fluid medium functioned by the temperature ranges of 25-75℃ and its results are compared with computational fluid dynamic(CFD)/heat transfer research(HTRI)analyzed *** 60 L/min flow rate was spotted as an optimum value for both shell and tube side *** STHE is operated with a 60 L/min flow rate under the different peened surfaces and evaluated its Stanton number,Nusselt number,logarithmic mean temperature difference(LMTD),overall heat transfer coefficient,number of transfer units(NTU),effectiveness,and exergy *** iron blasted SS peened surface was observed to have better SHTE performance like Stanton number(0.0012),Nusselt number(2180),reduced LMTD of 31℃,improved overall heat transfer co-efficient of 2400 W/(m^(2)·K),better NTU of 0.5532,good effectiveness value of 0.45162,and hiked exergy efficiency of 10% respectively.

关键词： penned surface performance analysis stainless steel shell and tube heat exchanger

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Insight into the activation of peroxymonosulfate by N-doped copper-based carbon for efficient degradation of organic pollutants:Synergy of nonradicals

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Chinese Chemical Letters 2025年第1期36卷 513-520页

作者： Mengmeng Ao Jian Wei Chuan-Shu He Heng Zhang Zhaokun Xiong Yonghui Song Bo Lai college of Environmental Sciences Liaoning UniversityShenyang 110036China State Key Laboratory of Hydraulics and Mountain River engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China

The contamination of water resources by phenolic compounds(PCs)presents a significant environmental hazard,necessitating the development of novel materials and methodologies for effective *** this study,a metallic copper-doped zeolitic imidazolate framework was pyrolyzed and designated as CuNC-20 for the activation of peroxymonosulfate(PMS)to degrade phenol(PE).Cu-NC-20 could effectively address the issue of metal agglomeration while simultaneously diminishing copper dissolution during the activation of PMS *** Cu-NC-20 catalyst exhibited a rapid degradation rate for PE across a broad pH range(3-9)and demonstrated high tolerance towards coexisting *** to scavenger experiments and electron paramagnetic resonance analysis,singlet oxygen(^(1)O_(2))and high-valent copperoxo(Cu(Ⅲ))were the predominant reactive oxygen species,indicating that the system was nonradicaldominated during the degradation *** quantitative structure-activity relationship(QSAR)between the oxidation rate constants of various substituted phenols and Hammett constants was *** indicated that the Cu-NC-20/PMS system had the optimal oxidation rate constant withσ^(-)correlation and exhibited a typical electrophilic reaction *** study provides a comprehensive understanding of the heterogeneous activation process for the selective removal of phenolic compounds.

关键词： N-doped copper-based carbon Phenolic compounds Peroxymonosulfate Nonradical pathway Quantitative structure-activity relationship(QSAR)

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