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Journal of magnesium and Alloys 2024年第1期12卷 332-344页

作者： Z.Y.Xue X.J.li J.H.Chu m.m.li D.N.Zou L.B.Tong School of metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China State Key Laboratory of Advanced Design and manufacturing for Vehicle Body Hunan UniversityChangsha 410082China

The poor corrosion and wear resistances of mg alloys seriously limit their potential applications in various *** conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient *** the current study,we design a double-layer epoxy composite coating on mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly *** outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)*** FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier *** Ce film connects the outer layer with the substrate,showing the transition *** corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling *** synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of mg alloys.

关键词： mg alloy Functionalized graphene Epoxy coating Corrosion/wear resistance Blocking layer

Finite Element Analysis of Residual Stress and Distortion in an Eccentric Ring Induced by Quenching

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材料热处理学报 2004年第5B期25卷 746-751页

作者： li m. Victor Portland State University PO Box 751-ME Portland OR 97207-075J USA

The residual stresses and distortion induced by quenching in an eccentric ring were investigated in this study with finite element method. The ring was made of AISI 52100 steel. A fully coupled 3D temperature-displacement analysis was performed to simulate heat transfer, phase transformations, and mechanical stresses and strains during the heating and subsequent quenching processes. Commercial FEA package ABAQUS/Standard 6.4 was used for the analyses along with user subroutines developed by the authors to model the thermal and mechanical constitutive behavior. The simulation results show that transformation plasticity plays an important role on the residual stress distribution.

关键词：残余应力有限元分析变形偏心环相变塑性

Element-Free modelling of Topological Gels with Peculiar multiaxial Large Deformation Behavior

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Acta mechanica Solida Sinica 2022年第5期35卷 880-890页

作者： D.m.li Jia-Hui liu Jia-Xuan Xie School of Civil Engineering and Architecture Wuhan University of TechnologyWuhan430070China School of Science Wuhan University of TechnologyWuhan430070China

With slidable cross-links along the polymer strands,topological gels can adjust their network topology in response to the imposed *** reported in experimental studies from the literature,the unique cross-linking strategy and the distinct deformation mechanism result in a peculiar multiaxial behavior with minimal strain-coupling between different principal directions at relatively low cross-linking *** paper presents an element-free modelling of the topological gels focusing on their nonlinear stress–strain behavior under general biaxial ***,conditions of uniaxial stretching and the three types of biaxial deformation,i.e.,equibiaxial stretching,pure shear deformation,and“two-step”biaxial deformation are *** numerical stress–strain curves for these conditions are compared against those from the literature.

关键词： Topological gel multiaxial deformation Large deformation Element-free method Hyperelasticity

ON SEVERAL NEW mETHODS TO POLAR DECOmPOSITION COmPUTATION

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Acta mechanica Solida Sinica 1998年第4期11卷 329-340页

作者： Huang, mJ li, m Fu, mF Nanchang Univ Inst Engn Mech Nanchang 330029 Peoples R China

In this paper, the polar decomposition of a deformation gradient tensor is analyzed in detail. The four new methods for polar decompositioncomputation are given: (1) the iterated method, (2) the principal invariant's method, (3) the principal rotation axis' s method, (4) the coordinate transformation's method. The iterated method makes it possible to establish the nonlinear finite element method based on polar decomposition. Furthermore, the material time derivatives of the stretch tensor and the rotation tensor are obtained by explicit and simple expressions.

关键词： polar decomposition deformation gradient stretch tensor rotation tensor large deformation and large rotation

The role of melt cooling rate on the interface between 18R and mg matrix in mg_(97)Zn_(1)Y_(2) alloys

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Journal of magnesium and Alloys 2023年第8期11卷 2883-2890页

作者： Q.Q.Jin X.H.Shao J.m.li Z.Z.Peng m.Lv B.Zhang Y.m.li X.L.ma materials Science and Engineering Research Center Guangxi University of Science and TechnologyLiuzhou 545006China Shenyang National Laboratory for materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of materials Science and Engineering Hebei University of Science and TechnologyShijiazhuangHebei 050018China

The role of melt cooling rate on the interface morphology and dislocation configuration between 18R long-period stacking ordered(LPSO)structure and mg matrix in mg_(97)Zn_(1)Y_(2)(at.%)alloys was investigated by atomic-scale HAADF-STEm *** 18R/mg interface is step-like both in the near-equilibrium alloy and non-equilibrium *** cooling rate makes the step size more regular and *** 54R structure can be observed at the interface in the near-equilibrium alloy,and the dislocations are highly ordered.54R and 54R′structure sandwiched by b1 and b2+b3 dislocation arrays,and new dislocation configuration can be detected at the interface in the non-equilibrium alloy,but the dislocations are less ordered.18R/mg interface containing 54R or 54R′in equilibrium width,parallel to the(010)plane,should be most stable based on elastic *** segregation of solute atoms and its strong interaction with dislocations dominate the LPSO/mg interface via diffusion-displacive transformation.

关键词： magnesium alloys Long-period stacking ordered phases Dislocations Interface structure

A mONTE CARLO SImULATION OF SECONDARY ELECTRON AND BACKSCATTERED ELECTRON ImAGES IN SCANNING ELECTRON mICROSCOPY

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Acta metallurgica Sinica(English Letters) 2005年第3期18卷 351-355页

作者： H.m.li Z.J.Ding HefeiNationalLaboratoryforPhysicalSciencesatmicroscaleandDepartmentofPhysics UniversityofScienceandTechnologyofChinaHefei230026China

A new parallel monte Carlo simulation method of secondary electron (SE) and back scattered electron images (BSE) of scanning electron microscopy (SEm) for a com plex geometric structure has been developed. This paper describes briefly the si mulation method and the modification to the conventional sampling method for the step length. Example simulation results have been obtained for several artifici al structures.

关键词： monte Carlo SEm secondary electrons backscattered electrons,

Numerical study on the resistance of rigid projectiles penetrating into semi-infinite concrete targets

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Acta mechanica Sinica 2021年第3期37卷 482-493,I0003页

作者： Huawei Yang Jie Zhang Zhiyong Wang Zhihua Wang Q.m.li College of management Science and Engineering Shanxi University of Finance and EconomicsTaiyuan 030006China Institute of Applied mechanics College of Mechanical and Vehicle EngineeringTaiyuan University of TechnologyTaiyuan 030024China Shanxi Key Laboratory of material Strength and Structural Impact Taiyuan University of TechnologyTaiyuan 030024China Department of mechanical Aerospace and Civil EngineeringSchool of EngineeringThe University of ManchesterManchester M139PLUK

A study on the resistance of rigid projectiles penetrating into semi-infinite concrete targets is performed in this *** data are analyzed to examine the penetration resistance during various stages of the penetration process.A numerical tool using AUTODYN hydrocode is applied in the *** numerical results on both deceleration-time history and depth of penetration of projectiles are in good agreement with experimental data,which demonstrate the feasibility of the numerical model in these *** on the numerical model with a two-staged pre-drilled hole,the rigid projectile penetration in tunneling stage is studied for concrete targets with different strengths in a wide range of impact *** results show that the penetration in tunnel stage can be divided into two different cases in terms of initial impact *** the first case,when the impact velocity is approximately less than 600 m/s,the deceleration depends on initial impact *** the second case,when the impact velocity is greater than 600 m/s,the effect of target inertia becomes apparent,which agrees with commonly used concrete penetration resistance equations based on cavity expansion model.

关键词： Rigid projectile Penetration resistance Entrance phase Inertial term Concrete target

A Simple and Unified model for Spanwise mixing in multistage Axial Flow Compressors

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Journal of Thermal Science 1992年第2期1卷 98-107页

作者： S.－m.li m.－Z.Chen GasTurbineLab. Dept.ofThermalEnergyTsinghuaUniversityBeijing100084 Dept.ofJetPropulsion BeijingUniv

A basic equation system for meridional throughflow fields in multistage axial flow compressors has been deduced, containing many unknown correlation terms,which describe different kinds of spanwise mixing mechanism in a unified *** equation system shows that spanwise mixing of meridional flows in compressors is attributed to three kinds of mechanism:molecular motion,turbulent diffusion,and circumferential non-uniformities,the last of which includes secondary flow effects and *** the equation system unifies the two models for spanwise mixing analyses by Adkins & Smith (1981) and Gallimore & Cumpsty (1986).With three kinds of apparent mixing coefficients defined and introduced into the basic equation system,a novel,much simpler equation system,without additional unknown correlation terms included,has been *** novel equa- tion system makes throughflow computations including mixing far easier for multistage *** has been rigorously shown that these apparent mixing coefficients contain full information of all the three kinds of mixing mechanism,so that the simpler equation system can also be taken as a unified model for meridional flows with all the kinds of the mixing *** of the flow through multistage machines have been made by incorporating the new model into a streamline curvature throughflow calculation method and the improved agreement with experimental data has been *** is believed that the simpler equation system can be applied to the flows not only in subsonic but in transonic and supersonic compressors if an appropriate model is proposed for the apparent mixing coefficients.

关键词： multistage axial flow compressors spanwise mixing meridional throughflow

Strain Growth in Containment Vessels

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Transactions of Tianjin University 2006年第B9期12卷 193-198页

作者： DONG Q li Q m ZHENG J Y School of mechanical Aerospace and Civil Engineering The University of Manchester PO Box 88 Manchester M60 1QD UK Institute of Chemical machinery Zhejiang University Hangzhou 310027 China

Strain growth is a phenomenon observed in containment vessels subjected to internal blast loading. The elastic response of the vessel may become larger in a later stage compared to its response during the initial stage. The dynamic responses of infinitely long cylindrical containment vessels subjected to uniformly-distributed internal blast loading are studied using LS-DYNA. The development of bending modes and the interaction between the breathing mode and bending modes are observed. The methodology developed for dynamic elastic buckling analysis is employed to study the strain growth phenomenon in explosion containment vessels. It is shown that the dynamic instable vibration of a containment vessel is the basic mechanism of strain growth.

关键词： strain growth containment vessel dynamic response impulsive loading

Improved Consensus Speed for Discrete-Time multi-agent Systems

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Journal of Donghua University(English Edition) 2013年第6期30卷 461-465页

作者： li m. li Q.-Q. Gao H.-L. School of Control Science and Engineering Shandong University Jinan 250061 China School of Electrical Engineering and Automation Qilu University of Technology Jinan 250061 China College of Automation South China University of Technology Guangzhou 510641 China

The consensus problem of a linear discrete-time multi- agent system with directed communication topologies was investigated. A protocol was designed to solve consensus with an improved convergence speed achieved by designing protocol gains. The clo6ed-loop *** system converged to an expected type of consensus function, which was divided into four types： zero, non- zero constant vector, bounded trajectories, and ramp trajectories. An algorithm was further provided to construct the protocol gains, which were determined in terms of a classical pole placement algorithm and a modified algebraic Riccati equation. Finally, an example to illustrate the effectiveness of theoretical results was presented.

关键词： discrete-time multi-agent consensus function consensus speed