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nonlinear behavior and Domain Feature at Oil/Water Interface

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Chinese Chemical Letters 2003年第10期14卷 1062-1065页

作者： Jin Zhang GAO, Kan Jun SUN, Wu YANGChemistry and Chemical Engineering College, Northwest Normal University, Lanzhou 730070 Chemistry and Chemical Engineering College Northwest Normal University Lanzhou 730070

Studies on nonlinear behavior at oil/water interface membrane were performed. This system showed rhythmic oscillations and chaos of electrical potential in a given concentration domain. The nonlinear behavior response at the liquid membrane apparently resembled that of biological chemoreceptive membrane. The possibility of developing a new type of chemical sensor with the ability to simulate substance equilibrium in living organisms was suggested in the paper.

关键词： nonlinear behavior oscillations oil/water interface domain.

THE USE OF VISCO-ELASTOPLASTIC DAMAGE CONSTITUTIVE MODEL TO SIMULATE nonlinear behavior OF CONCRETE

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Acta Mechanica Solida Sinica 2011年第5期24卷 411-428页

作者： Jun Liu Gao Lin Bing Fu Hong Zhong State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China Department of Civil and Structural Engineering The Hong Kong Polytechnic University Hong Kong China

A visco-elastoplastic damage constitutive model is proposed for simulating non-linear behavior of concrete. Based on traditional plastic theory, the irreversible deformation is simulated in effective stress space. In order to reflect different stiffness degradation mechanism of concrete under tensile and compressive loading conditions, both tensile and compressive damage variables are introduced, and then on the basis of energy release rate, the model is firmly derived within the concept of irreversible thermodynamics. The rate-dependent model is considered by introducing viscous regularization into the inelastic strain and damage variable, and combined with an additional elastic condition. Fully implicit backward-Euler algorithm is used to perform constitutive integration. Results of numerical examples using the proposed model agree well with test results for specimens under uniaxial tension and compression, biaxial loading and triaxial loading. Failure processes of single-edge-notched （SEN） beam and double-edge-notched （DEN） specimen are also simulated to further validate the proposed model.

关键词： damage rate-dependent plasticity thermodynamics energy release rate nonlinear behavior concrete

nonlinear DYNAMIC behavior OF VISCOELATIC TPANSMISSION BELT

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Chinese Journal of Mechanical Engineering 2003年第4期16卷 384-386页

作者： LiYinghui GaoQing JianKailin YinXuegang DepartmentofAppliedMachanicsandEngineering SouthwestJiaotongUniversityChengdu610031China InstituteofEngineeringMechanics ChongqingUniversityChongqing400044China

The nonlinear dynamic responses of viscoelastic axially transmission beltsare investigated and the Kelvin viscoelastic differential constitutive model is employed tocharacterize the material property of belts. The generalized equation of motion is obtained for aviscoelatic axially transmission belts with geometric nonlinearity first, and then is reduced to bea set of second-order nonlinear ordinary differential equations by applying Galerkin's method.Finally, the effects of viscosity parameter and elastic parameter and the moving velocity of thebelts on the transient responses are investigated by the research of digital simulation.

关键词： Transmission belt Viscoelastic constitutive law nonlinear behavior

Three-dimensional general magneto-electro-elastic finite element model for multiphysics nonlinear analysis of layered composites

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Applied Mathematics and Mechanics(English Edition) 2023年第1期44卷 53-72页

作者： Zheng GONG Yinxiao ZHANG Ernian PAN Chao ZHANG School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications Xi'an 710072China Civil Engineering and Institute of Pioneer Semiconductor Innovation Yang Ming Chiao Tung UniversityHsinchu 30010TaiwanChina School of Civil Aviation Northwestern Polytechnical UniversityXi'an 710072China

In this paper,by defining a general potential energy for the multiphase coupled multiferroics and applying the minimum energy principle,the coupled governing equations are derived.This system of equations is then discretized as a general three-dimensional(3D)finite element(FE)model based on the COMSOL software.After validating the formulation,it is then applied to the analysis and design of the common sandwich structure of multiferroics composites.Under the typical static loading,the effects of general lateral boundary conditions,material grading,nonlinearity,as well as polarization orientation on the composites are analyzed.For the magneto-electro-elastic(MEE)sandwich made of piezoelectric BaTiO_(3)and magnetostrictive CoFe_(2)O_(4)with different stacking sequences,various interesting features are observed which should be very helpful for the design of high-performance multiphase composites.

关键词： multiferroics sandwich composite magneto-electro-elastic(MEE)material multilayered plate nonlinear behavior

nonlinear dynamics of cell migration in anisotropic microenvironment

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Chinese Physics B 2021年第9期30卷 166-177页

作者：刘艳平何达焦阳李国强郑钰樊琪慧王高姚静如陈果娄四龙刘雳宇 Chongqing Key Laboratory of Soft Condensed Matter Physics and Smart Materials College of PhysicsChongqing UniversityChongqing 401331China Spine Surgery Beijing Jishuitan HospitalBeijing 100035China Department of Physics Arizona State UniversityTempeArizona 85287USA Materials Science and Engineering Arizona State UniversityTempeArizona 85287USA Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics Institute of PhysicsChinese Academy of Sciences(CAS)Beijing 100190China Department of Neurosurgery Chongqing University Cancer HospitalChongqing 400030China

Cell migration in anisotropic microenvironment plays an important role in the development of normal tissues and organs as well as neoplasm progression,e.g.,osteogenic differentiation of embryonic stem cells was facilitated on stiffer substrates,indicating that the mechanical signals greatly affect both early and terminal differentiation of embryonic stem cells.However,the effect of anisotropy on cell migration dynamics,in particular,in terms of acceleration profiles which is important for recognizing dynamics modes of cell migration and analyzing the regulation mechanisms of microenvironment in mechanical signal transmission,has not been systematically investigated.In this work,we firstly rigorously investigate and quantify the differences between persistent random walk and anisotropic persistent random walk models based on the analysis of cell migration trajectories and velocity auto-covariance function,both qualitatively and quantitatively.Secondly,we introduce the concepts of positive and negative anisotropy based on the motility parameters to study the effect of anisotropy on acceleration profiles,especially the nonlinear decrease and non-monotonic behaviors.We particularly elaborate and discuss the mechanisms,and physical insights of non-monotonic behaviors in the case of positive anisotropy,focusing on the force exerted on migrating cells.Finally,we analyze two types of in vitro cell migration experiments and verify the universality of nonlinear decrease and the consistence of non-monotonic behaviors with numerical results.We conclude that the anisotropy of microenvironment is the cause of the non-monotonic and nonlinear dynamics,and the anisotropic persistent random walk can be as a suitable tool to analyze in vitro cell migration with different combinations of motility parameters.Our analysis provides new insights into the dynamics of cell migration in complex microenvironment,which also has implications in tissue engineering and cancer research.

关键词： cell migration nonlinear behavior motility parameter acceleration profile anisotropic microenvironment

Strength criterion of porous media: Application of homogenization techniques

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第1期9卷 62-73页

作者： L. Dormieux E. Lemarchand D. Kondo S. Brach CNRS UMR 8205 ENPC Laboratoire Navier 6 et 8 avenue Blaise Pascal 77455 Marne-la-Vallée France UPMC Institut Jean le Rond d’Alembert Paris France

The present paper aims at giving some general ideas concerning the micromechanical approach of the strength of a porous material. It is shown that its determination theoretically amounts to solving a nonlinear boundary value problem defined on a representative elementary volume(REV). The principle of nonlinear homogenization is illustrated based on the case of a solid phase having a Green’s strength criterion. An original refinement of the so-called secant method(based on two reference strains) is also provided. The paper also describes the main feature of the Gurson’s model which implements the principle of limit analysis on a conceptual model of hollow sphere. The last part of the paper gives some ideas concerning poromechanical couplings.

关键词： Strength criterion Porous media Homogenization techniques nonlinear behavior Limit analysis Gurson’s model

Fishbone Mode Excited by Deeply Trapped Energetic Beam Ions in EAST

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Plasma Science and Technology 2016年第6期18卷 595-600页

作者：郑婷吴斌徐立清胡纯栋臧庆丁斯晔李颖颖伍兴权王进芳沈飙钟国强李昊石同辉 School of Physics and Materials Science Anhui University Hefei 230039 China Institute of Plasma Physics Chinese Academy of Sciences Hefei 230031 China

This paper describes the fishbone mode phenomena during the injection of highpower neutral beams in EAST（Experimental Advanced Superconducting Tokamak）.The features of the fishbone mode are presented.The change in frequency of the mode during a fishbone burst is from 1 kHz to 6 kHz.The nonlinear behavior of the fishbone mode is analyzed by using a prey-predator model,which is consistent with the experimental results.This model indicates that the periodic oscillations of the fishbone mode always occur near the critical value of fast ion beta.Furthermore,the neutral beam analysis for the discharge is done by using the NUBEAM module of the TRANSP code.According to the numerical simulation results and theoretical calculation,it can be concluded that the fishbone mode is driven by the deeply trapped energetic beam ions in EAST.

关键词： EAST NBI fishbone mode TRANSP code nonlinear behavior

Numerical characteristics of the full operator hybrid simulation method

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Earthquake Engineering and Engineering Vibration 2011年第3期10卷 453-463页

作者： Chung-Chan Hung Yong-Song Chen Department of Civil Engineering Central University （NCU） Chinese Taipei Department of Mechanical Engineering Chung Cheng University （NCCU） Chinese Taipei

The full operator method （FOM） has been proposed to overcome some of the shortcomings of the commonly used operator splitting method （OSM）. In particular, the FOM is improved by increasing the accuracy of both the predictor and corrector using the estimated tangent stiffness of the tested structure. The numerical characteristics of the FOM, including stability and accuracy, are investigated in this study. It is shown that FOM is conditionally stable. The stability and accuracy characteristics are dependent on the accuracy of the estimated tangent stiffness and the parameters associated with the acceleration variation in the time-stepping integration method. Mass-spring systems with different types of nonlinearity, including hardening, stiffening, and softening behavior, are used to evaluate the performance of the FOM. It is found that the FOM can capture these types of nonlinearity with satisfactory accuracy. Using a prototype 12-story composite coupled wall system, the influences of the strong nonlinearity of the system as well as the displacement control errors from hydraulic actuators on the performance of the FOM are explored. The results show that the FOM is capable of generating reasonably accurate results despite the presence of strong structural nonlinearity and displacement control errors.

关键词： hybrid simulation tangent stiffness numerical characteristic composite coupled wall system collapse behavior nonlinear behavior

nonlinear characteristics of circular-cylinder piezoelectric power harvester near resonance based on flow-induced flexural vibration mode

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Applied Mathematics and Mechanics(English Edition) 2014年第2期35卷 229-236页

作者：王海仁谢捷敏谢旋胡元太王骥 Purple Mountain Observatory Chinese Academy of Sciences Department of Mechanics Huazhong University of Science and Technology Piezoelectric Device Laboratory Department of Mechanics and Engineering ScienceSchool of Mechanical Engineering and MechanicsNingbo University

The nonlinear behaviors of a circular-cylinder piezoelectric power harvester （CCPPH） near resonance are analyzed based on the flow-induced flexural vibration mode. The geometrically-nonlinear effect of the cylinder is studied with considering the in-plane extension incidental to the large defection. The boundary electric charges generated from two deformation modes, flexure and in-plane extension, were distinguished with each other because the charge corresponding to the latter mode produces no contribution to the output current. Numerical results on output powers show that there are multi- valuedness and jump behaviors.

关键词： piezoelectric power harvester nonlinear behavior large deflection in-plane extension multivaluedness