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Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 139-156页

作者： H.HOSSEINI O.BALILASHAKI Department of Mechanical engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. Stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

关键词： cylindrical cavity O353.4 point source porous medium stress concentration wave-field transformation

A review of over-discharge protection through prelithiation in working lithium-ion batteries

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Journal of Energy Chemistry 2025年第2期101卷 437-452页

作者： Hanchen Wang Yingtian Liu Mingze Jiang Qiang Zhang School of Aerospace engineering National Engineering Research Center of Neuromodulation Tsinghua University Tsinghua Center for Green Chemical engineering Electrification Department of Chemical Engineering Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Tsinghua University

The demand for high safety and high reliability lithium-ion batteries(LIBs) is strongly considered for practical ***,due to their inherent self-discharge properties or abuse,LIBs face the threat of over-discharge,which induces premature end of life and increased risk of thermal *** addition,a strong demand for batteries with zero-volt storage is strongly considered for aerospace and implantable medical *** this review,we firstly introduce the necessity and the importance of over-discharge and zero-volt protection for *** mechanism of damage to the Cu current collectors and SEI induced by potential changes during over-discharge is *** current over-discharge protection strategies based on whether the zero-crossing potential of the electrodes is ***,the fresh insights into the material design of cathode prelithiation additives are presented from the perspective of over-discharge protection.

关键词： Electrode potential regulation Electrode prelithiation Li-ion batteries Over-discharge protection Zero-volt storage

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

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

A binary eutectic electrolyte design for high-temperature interface-compatible Zn-ion batteries

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Journal of Energy Chemistry 2025年第2期101卷 587-597页

作者： Guomin Li Wentao Wen Kefeng Ouyang Yanyi Wang Jianhui Zhu Ming Yang Hongwei Mi Ning Zhao Peixin Zhang Dingtao Ma College of Chemistry and Environmental engineering Shenzhen University School of Materials Science and engineering Harbin Institute of Technology (Shenzhen) School of Materials and Environmental engineering Shenzhen Polytechnic Guangdong Flexible Wearable Energy and Tools engineering Technology Research Center

The deterioration of aqueous zinc-ion batteries（AZIBs） is confronted with challenges such as unregulated Zn2+diffusion,dendrite growth and severe decay in battery performance under harsh ***,a design concept of eutectic electrolyte is presented by mixing long chain polymer molecules,polyethylene glycol dimethyl ether（PEGDME）,with H2O based on zinc trifluoromethyl sulfonate(Zn（OTf）2),to reconstruct the Zn2+solvated structure and in situ modified the adsorption layer on Zn electrode *** dynamics simulations（MD）,density functional theory（DFT） calculations were combined with experiment to prove that the long-chain polymer-PEGDME could effectively reduce side reactions,change the solvation structure of the electrolyte and priority absorbed on Zn（002）,achieving a stable dendrite-free Zn *** to the comprehensive regulation of solvation structure and zinc deposition by PEGDME,it can stably cycle for over 3200 h at room temperature at 0.5 mA/cm2and 0.5 mAh/*** at high-temperature environments of 60℃,it can steadily work for more than 800 cycles（1600 h）.Improved cyclic stability and rate performance of aqueous Zn‖VO2batteries in modified electrolyte were also achieved at both room and high *** that,the demonstration of stable and high-capacity Zn‖VO2pouch cells also implies its practical application.

关键词： Dendrite suppression Eutectic electrolyte High temperature Solvation structure Zn anode

Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAEI H.GHANDVAR E.JUMAEV S.KHATIR T.CUONG-LE School of Mechanical engineering Babol Noshirvani University of Technology Department of Mechanical engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for engineering Application and Technology Solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

关键词： double curved beam finite element method functionally graded porous (FGP) material intermediate straight beam O313 vibration analysis

Effects of bidirectional interaction on inelastic seismic response:When is its effect significant?

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Earthquake engineering and engineering Vibration 2025年第1期24卷 113-134页

作者： Atanu Santra Rana Roy Department of Aerospace engineering and Applied Mechanics Indian Institute of Engineering Science and TechnologyShibpur 711103India

Motivated by the early works on bidirectional interaction and the breakthrough to estimate seismic response to bidirectional shaking via unidirectional analysis,it is essential to answer the question:When is the interaction effect significant?Early works concluded that the effect of interaction is pronounced for stiff systems;consequently,the straightforward method for estimating seismic response to bidirectional excitation by using unidirectional analyses is verified primarily for short period ***,it is essential to identify the domain of significance for bidirectional interaction before adopting this simple methodology in *** parametrically defined systems with elastoplastic and degrading hysteresis models are studied under near-fault motions,assuming strength-independent and strength-dependent *** force-based and displacement-based analyses,conducted in parallel,reveal that the interaction effect is considerable for stiff systems,especially with degrading characteristics in a relatively low inelasticity ***,the bidirectional effect may be significant even for highly flexible systems,especially for residual deformation,which in earlier works was *** range of significance depends on the hysteresis model,system parameters,and response *** analysis is carried out with the results of the case studies,and the derived regression models may be used for a preliminary assessment of the impact of interaction in advance.

关键词： bidirectional residual forward-directive fling force-based displacement-based regression

Influence of a non-free field subsurface seismic history on the liquefaction resistance of sandy soils

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Earthquake engineering and engineering Vibration 2025年第1期24卷 53-68页

作者： Liu Liteng Wang Xiaolei Liu Run Liu Libo Cao Zhipeng Zhang Fan College of Civil engineering Hebei University of EngineeringHandan 056038China Institute of Geotechnical engineering Tianjin UniversityTianjin 300072China

Seismic-induced liquefaction of sandy soils can fail foundations in the vicinity of *** investigate the effect of a non-free field subsurface seismic history on the ability of saturated sandy soils to resist liquefaction,four shaking events with different accelerations were input to the sandy soils in the *** results of the study revealed that:(1)Shallow soils that are not free-field undergo acceleration amplification effects after being subjected to seismic loading.(2)Building overburden pressure reduces the sensitivity of the shallow soils directly below in small and moderate earthquakes,which are more prone to rearranging and forming unstable structures under strong seismic *** excess pore pressure response on the load side resembles that of a free site,with the depth range of the liquefaction strength of soils affected by the seismic history,increasing progressively as input seismic intensity increases.(3)After experiencing earthquakes of different intensities,the excess pore pressure directly below the building overburden pressure at 0.1 m and 0.2 m is greater than that at the *** the same time,the side of the building structure is more prone to liquefaction than the soil directly below it.

关键词： non-free site seismic history liquefaction resistance excess pore pressure shaking table test

Modification of Maxwell model for conductivity prediction of carbon nanotubes-filled polymer composites with tunneling effect

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 25-36页

作者： Jue ZHU Longyuan LI Ningtao ZHU Zhejiang Provincial engineering Research Center for the Safety of Pressure Vessel and Pipeline Key Laboratory of Impact and Safety engineering (Ningbo University) Ministry of Education School of engineering Computing and Mathematics University of Plymouth Xi'an Zhanshi Testing & engineering Co.Ltd.

Carbon nanotubes(CNTs) have garnered great attention in recent years due to their outstanding electrical, thermal, and mechanical properties. The incorporation of small amounts of CNTs in polymers can substantially improve the sensitivity of the polymer's electrical conductivity. This paper presents a modified Maxwell model to evaluate the electrical conductivity of CNTs-filled polymer composites by introducing a transition zone to account for the tunneling effect. In this modified Maxwell model, the CNTs-filled polymer composite is modeled as a three-phase composite, consisting of a matrix(polymer), inclusions(CNTs), and a transition zone(tunneling zone). The effective electrical conductivity(EEC) of the composite is calculated based on the volume fractions and electrical conductivities of the matrix, inclusions, and transition zone. The model's validity is confirmed through the use of available test data, which demonstrates its capability to accurately capture the nonlinear conductivity behavior observed in CNTs-polymer composites. This study offers valuable insights into the design of high-performance conductive polymer nanocomposites, and enhances the understanding of electrical conduction mechanisms in CNT-dispersed polymer composites.

关键词： carbon nanotube (CNT) composite electrical conductivity Maxwell model O242.2 O441.1 polymer tunneling