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A robust implicit high-order discontinuous Galerkin method for solving compressible Navier-Stokes equations on arbitrary grids

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Acta Mechanica Sinica 2024年第8期40卷 96-119页

作者： Jia Yan Xiaoquan Yang Peifen Weng Shanghai institute of Applied Mathematics and mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai200072China College of Energy and mechanical engineering Shanghai University of Electric PowerShanghai200090China

The primary impediments impeding the implementation of high-order methods in simulating viscous flow over complex configurations are robustness and *** challenges impose significant constraints on computational efficiency,particularly in the domain of engineering *** address these concerns,this paper proposes a robust implicit high-order discontinuous Galerkin(DG)method for solving compressible Navier-Stokes(NS)equations on arbitrary *** method achieves a favorable equilibrium between computational stability and *** solve the linear system,an exact Jacobian matrix solving strategy is employed for preconditioning and matrix-vector generation in the generalized minimal residual(GMRES)*** approach mitigates numerical errors in Jacobian solution during implicit calculations and facilitates the implementation of an adaptive Courant-Friedrichs-Lewy(CFL)number increasing strategy,with the aim of improving convergence and *** further enhance the applicability of the proposed method for intricate grid distortions,all simulations are performed in the reference *** practice significantly improves the reversibility of the mass matrix in implicit calculations.A comprehensive analysis of various parameters influencing computational stability and efficiency is conducted,including CFL number,Krylov subspace size,and GMRES convergence *** computed results from a series of numerical test cases demonstrate the promising results achieved by combining the DG method,GMRES solver,exact Jacobian matrix,adaptive CFL number,and reference domain calculations in terms of robustness,convergence,and *** analysis results can serve as a reference for implicit computation in high-order calculations.

关键词： Discontinuous Galerkin method Exact Jacobian matrix GMRES solver Adaptive CFL number Reference domain High-order

Dynamics of a rotating ring-stiffened sandwich conical shell with an auxetic honeycomb core

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Applied Mathematics and mechanics(English Edition) 2024年第6期45卷 963-982页

作者： S.JAHANGIRI A.GHORBANPOUR ARANI Z.KHODDAMI MARAGHI Department of Solid mechanics Faculty of Mechanical EngineeringUniversity of KashanKashan ***Iran Faculty of engineering Mahallat Institute of Higher EducationMahallat ***Iran

The free vibration analysis of a rotating sandwich conical shell with a reentrant auxetic honeycomb core and homogenous isotropic face layers reinforced with a ring support is *** shell is modeled utilizing the first-order shear deformation theory(FSDT)incorporating the relative,centripetal,and Coriolis accelerations alongside the initial hoop tension created by the *** governing equations,compatibility conditions,and boundary conditions are attained using Hamilton’s *** trigonometric functions,an analytical solution is derived in the circumferential direction,and a numerical one is presented in the meridional direction via the differential quadrature method(DQM).The effects of various factors on the critical rotational speeds and forward and backward frequencies of the shell are *** present work is the first theoretical work regarding the dynamic analysis of a rotating sandwich conical shell with an auxetic honeycomb core strengthened with a ring support.

关键词： free vibration conical shell rotating shell ring support auxetic honeycomb

Current collectors' effects on the electrochemical performance of LiNi0.6Co0.2Mn0.2O2 suspension electrodes for lithium slurry battery

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Green Energy & Environment 2024年第8期9卷 1306-1313页

作者： Linshan Peng Yufei Ren Zhaoqiang Yin Zhitong Wang Xiangkun Wu Lan Zhang CAS Key Laboratory of Green process and engineering Beijing Key Laboratory of Ionic Liquids Clean ProcessState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of Sciences School of Chemical engineering University of Chinese Academy of Sciences Hefei University institute of mechanics Chinese Academy of Sciences Langfang Green Industrial Technology Center

Take after the advantages of lithium-ion battery（LIB） and redox flow battery（RFB）, semi-solid flow battery（SSFB） is a promising electrochemical energy storage device in renewable energy utilization. The flowable slurry electrode realizes decouple of energy and power density,while it also brings about new challenge to SSFBs, electron transport between active material and the out circuit. In this consideration, three types of current collectors（CCs） are applied to study the resistance and electrochemical performances of slurry cathodes within pouch cells for the first time. It proves that the electronic resistance（Re） between slurry electrode and the CC plays a decisive role in SSFB operation, and it is so large when Al foil is adopted that the cell cannot even work. Contact angle between Ketjen black（KB） slurry without active material（AM） and the CC is a preliminarily sign for the Re, the smaller the angle, the lower the resistance, and the better electrochemical performance of the cell.

关键词： Semi-solid flow battery Slurry electrode Current collector Electronic resistance Carbon coated Al

An artificial neural network based deep collocation method for the solution of transient linear and nonlinear partial differential equations

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Frontiers of Structural and Civil engineering 2024年第8期18卷 1296-1310页

作者： Abhishek MISHRA Cosmin ANITESCU Pattabhi Ramaiah BUDARAPU Sundararajan NATARAJAN Pandu Rang VUNDAVILLI Timon RABCZUK School of mechanical Sciences Indian Institute of TechnologyBhubaneswar 752050India institute of Structural mechanics Bauhaus University of WeimarWeimar 99423Germany Department of mechanical engineering Indian Institute of Technology MadrasChennai 600036India

A combined deep machine learning(DML)and collocation based approach to solve the partial differential equations using artificial neural networks is *** developed method is applied to solve problems governed by the Sine–Gordon equation(SGE),the scalar wave equation and *** methods are studied:one is a space-time formulation and the other is a semi-discrete method based on an implicit Runge–Kutta(RK)time *** methodology is implemented using the Tensorflow framework and it is tested on several numerical *** on the results,the relative normalized error was observed to be less than 5%in all cases.

关键词： collocation method artificial neural networks deep machine learning Sine-Gordon equation transient wave equation dynamic scalar and elasto-dynamic equation Runge-Kutta method

Multi-Material magnetic field-assisted additive manufacturing system for flexible actuators with programmable magnetic arrangements

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Frontiers of mechanical engineering 2024年第2期19卷 109-120页

作者： Yujie HUANG Haonan SUN Chengqian ZHANG Ruoxiang GAO Hongyao SHEN Peng ZHAO The State Key Laboratory of Fluid Power and Mechatronic Systems College of Mechanical EngineeringZhejiang UniversityHangzhou 310027China The Key Laboratory of 3D Printing process and Equipment of Zhejiang Province College of Mechanical EngineeringZhejiang UniversityHangzhou 310027China Center for X-mechanics Department of Engineering MechanicsZhejiang UniversityHangzhou 310027China

Manufacturing flexible magnetic-driven actuators with complex structures and magnetic arrangements to achieve diverse functionalities is becoming a popular *** various manufacturing technologies,magnetic-assisted digital light processing(DLP)stands out because it enables precise manufacturing of macro-scale structures and micro-scale distributions with the assistance of an external magnetic *** research on manufacturing magnetic flexible actuators mostly employs single materials,which limits the magnetic driving performance to some *** on these characterizations,we propose a multi-material magnetic field-assisted DLP technology to produce flexible actuators with an accuracy of 200μ*** flexible actuators are printed using two materials with different mechanical and magnetic *** the interface connectivity of multi-material printing,the effect of interfaces on mechanical properties is also *** results indicate good chemical affinity between the two materials we *** overlap or connection length of the interface moderately improves the tensile strength of multi-material *** addition,we investigate the influence of the volume fraction of the magnetic part on *** and experimental results indicate that increasing the volume ratio(20%to 50%)of the magnetic structure can enhance the responsiveness of the actuator(more than 50%).Finally,we successfully manufacture two multi-material flexible actuators with specific magnetic arrangements:a multi-legged crawling robot and a flexible gripper capable of crawling and grasping *** results confirm that this method will pave the way for further research on the precise fabrication of magnetic flexible actuators with diverse functionalities.

关键词： multi-material magnetic field-assisted manufacturing digital light processing flexible actuators magnetic arrangement

Theoretical and experimental study of a bi-stable piezoelectric energy harvester under hybrid galloping and band-limited random excitations

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Applied Mathematics and mechanics(English Edition) 2024年第3期45卷 461-478页

作者： Haitao LI Tianyu ZHENG Weiyang QIN Ruilan TIAN Hu DING J.C.JI Liqun CHEN Department of engineering mechanics North University of ChinaTaiyuan 030051China Department of engineering mechanics Northwestern Polytechnical UniversityXi'an 710072China Department of engineering mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Shanghai Key Laboratory of mechanics in Energy engineering Shanghai Frontier Science Center of MechnoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China School of mechanical and Mechatronic engineering University of Technology SydneyNew South Wales 2007Australia

In the practical environment,it is very common for the simultaneous occurrence of base excitation and *** the combined energy of vibration and wind with a single energy harvesting structure is *** this purpose,the effects of the wind speed and random excitation level are investigated with the stochastic averaging method(SAM)based on the energy *** results of the analytical prediction are verified with the Monte-Carlo method(MCM).The numerical simulation shows that the introduction of wind can reduce the critical excitation level for triggering an inter-well jump and make a bi-stable energy harvester(BEH)realize the performance enhancement for a weak base ***,as the strength of the wind increases to a particular level,the influence of the random base excitation on the dynamic responses is weakened,and the system exhibits a periodic galloping response.A comparison between a BEH and a linear energy harvester(LEH)indicates that the BEH demonstrates inferior performance for high-speed *** experiments are conducted to investigate the validity of the theoretical prediction and numerical *** experimental findings also show that strong random excitation is favorable for the BEH in the range of low wind ***,as the speed of the incoming wind is up to a particular level,the disadvantage of the BEH becomes clear and evident.

关键词： bi-stability inter-well response galloping band-limited random

Simulation and analysis of soil homogenization drills based on discrete element method and response surface methodology

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Particuology 2024年第5期88卷 128-148页

作者： Zhipeng Wang Tong Zhu Youzhao Wang Song Yang Feng Ma Xu Li institute of process Equipment and Environmental engineering School of Mechanical Engineering and AutomationNortheastern UniversityShenyang110819China Liaoning Coning Testing Co. Ltd.Shenyang110170 China

Currently,rotary drilling is one of the main pieces of equipment used for in-situ remediation of contaminated ***,this equipment has problems such as uneven mixing and low utilization efficiency,which affect the efficiency of in-situ soil *** improve the efficiency of in-situ soil remediation,this paper takes contaminated black soil as the research object,and the structural design of the new three-stage soil remediation auger is carried out based on *** mixing process of soil and heavy metal passivator under different motion and structural parameters was investigated by the discrete element method(DEM)and response surface *** experimental design was based on rotational speed,homogenizing mixing time,crushing section pitch,and homogenizing section pitch as factors,and soil fragmentation ratio,the coefficient of dispersion,and torque as optimization *** kinematic and structural parameters of the three-stage auger drill bit were then optimized using the one-factor method,the orthogonal test,and the response surface methodology,*** test method uses a one-way test to determine the central level value of the orthogonal test and a comprehensive balance method to determine the best combination of parameters for the orthogonal test,which is then used as the central value of the response surface test for parameter *** optimal combinations of kinematic and structural parameters of the three-stage auger drill bit are determined and validated using response surface *** optimum combination of parameters was found to be a speed of 129 rpm,a homogenizing mixing time of 24 s,a pitch of 165 mm in the crushing section,and a pitch of 132 mm in the homogenizing *** error between the optimal value of the predicted model using the response surface method and the actual simulated value under the optimal parameters is 4.2%,4.9%,and 5.3%,*** optimized factor parameters provide a refe

关键词： Black soil Mixing homogeneity Orthogonal method Response surface methodology Discrete element method Soil remediation

Passive particles driven by self-propelled particle:The wake effect

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Chinese Physics B 2024年第4期33卷 500-507页

作者：郑凯选汪静文王世锋聂德明 institute of Fluid mechanics China Jiliang UniversityHangzhou 310018China Department of mechanical engineering Hangzhou Vocational&Technical CollegeHangzhou 310018China

This work focuses on numerically studying hydrodynamic interaction between a passive particle and a self-propelled particle,termed a squirmer,by using a two-dimensional lattice Boltzmann method(LBM).It is found that the squirmer can capture a passive particle and propel it simultaneously,provided the passive particle is situated within the squirmer's *** research shows that the critical capture distance,which determines whether the particle is captured,primarily depends on the intensity of the squirmer's *** stronger dipolarity of squirmer results in an increased critical capture ***,the Reynolds number is found to have minimal influence on this ***,the passive particle,when driven by the squirmer's wake,contributes to a reduction in the squirmer's *** results in a mutual acceleration for both *** findings can provide valuable perspectives for formulating the principles of reducing the drag of micro-swimmers and help to achieve the goal of using micro-swimmers to transport goods without physical tethers.

关键词： lattice Boltzmann method(LBM) self-propelled particles particle-laden flow

Dynamics and vibration reduction performance of asymmetric tristable nonlinear energy sink

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Applied Mathematics and mechanics(English Edition) 2024年第3期45卷 389-406页

作者： Hongyan CHEN Youcheng ZENG Hu DING Siukai LAI Liqun CHEN School of mechanical engineering University of Science and Technology BeijingBeijing 100083China Shanghai Key Laboratory of mechanics in Energy engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China Department of Civil and Environmental engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina

With its complex nonlinear dynamic behavior,the tristable system has shown excellent performance in areas such as energy harvesting and vibration suppression,and has attracted a lot of *** this paper,an asymmetric tristable design is proposed to improve the vibration suppression efficiency of nonlinear energy sinks(NESs)for the first *** proposed asymmetric tristable NES(ATNES)is composed of a pair of oblique springs and a vertical ***,the three stable states,symmetric and asymmetric,can be achieved by the adjustment of the distance and stiffness asymmetry of the oblique *** governing equations of a linear oscillator(LO)coupled with the ATNES are *** approximate analytical solution to the coupled system is obtained by the harmonic balance method(HBM)and verified *** vibration suppression efficiency of three types of ATNES is *** results show that the asymmetric design can improve the efficiency of vibration reduction through comparing the chaotic motion of the NES oscillator between asymmetric steady *** addition,compared with the symmetrical tristable NES(TNES),the ATNES can effectively control smaller structural *** other words,the ATNES can effectively solve the threshold problem of TNES failure to weak ***,this paper reveals the vibration reduction mechanism of the ATNES,and provides a pathway to expand the effective excitation amplitude range of the NES.

关键词： asymmetric nonlinear energy sink(NES) tristable vibration control po-tential barrier