力学进展

ENGINEERING SCIENCES AND APPLIED MECHANICS\\(PART 1) ——　 IN MEMORIAL OF TSIEN HSUE-SHEN'S 100 TH ANNIVERSARY

Che-Min Cheng

2011, 41(6): 639-641. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-178

Abstract(2093)

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TSIEN HSUE-SHEN AND SYSTEM SCIENCES—— IN MEMORIAL OF TSIEN HSUE-SHEN'S 100 TH ANNIVERSARY

Lu Jiang

2011, 41(6): 642-646. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-164

Abstract(2057)

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ADVANCES IN DISCRETE DISLOCATION MECHANISM ON SUBMICRO CRYSTAL ATYPICAL PLASTICITY

Zhuo Zhuang, Yinani Cui, Yuan Gao, Zhanli Liu

2011, 41(6): 647-667. doi: 10.6052/1000-0992-2011-6-lxjzJ2010-131

Abstract(2623)

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In recent ten years, with the rapid development of experimental technology, the crystal plastic behavior in sub-micron scale has been well investigated. Numbers of atypical experimental data and theoretical results are revealed. However, they could not be explained by the classical plastic theory in a macro-scale and strain gradient plastic theory in a micro-scale. There are many scientific issues to be resolved. To further investigate the physical nature behind these phenomena, the researchers are trying to find the new theoretic model and numerical method to reveal the characteristics of plastic flow. The defect energy theory and discrete dislocation dynamics method have been proposed in order to describe the evolution of dislocation nucleation, multiplication, starvation and annihilation, and so on. In this paper, the research advances are general reviewed on the relevant experiment methods and data, the theoretical models and numerical methods of crystal atypical plasticity dominated by discrete dislocation mechanism in the sub-micron scale.

PROGRESS IN BYPASS TRANSITION INDUCED BY FREE-STREAM DISTURBANCE

Chong Pan, Jinjun Wang

2011, 41(6): 668-685. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-070

Abstract(2692)

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Progress in bypass transition induced by free-stream disturbance is reviewed in this paper. Free-stream disturbance, as the forcing environment, can be divided into two categories, free-stream turbulence and wake. The definition, classification and general route of bypass transition is presented first, followed by reviewing the characteristics and physics of FST-induced bypass transition. In this scenario, the topics of receptivity process, transient growth theory, Klebanoff mode, streak instability, turbulent spot and breakdown have all been covered. Moreover, we go further to review the previous studies on bypass transition induced by wake, both the passage wake and the wake containing large scale coherent vortices are included. Finally, the perspective for future investigations is forcasted.

ADVANCES AND PROSPECTS OF THE REDUCED ORDER\\ MODEL FOR UNSTEADY FLOW AND ITS APPLICATION

Gang Chen, Yueming Li

2011, 41(6): 686-701. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-009

Abstract(3410)

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With the development of the large scale numerical simulation,computational fluid dynamics and computational solid mechanics couplesimulation becomes the powerful accurate tool in engineering analysis. Butthe large computation cost postpones its widely application in design.Reduced order model (ROM) for unsteady flow field, with good accuracy, loworder and high efficiency, gives an opportunity to CFD/CSD couple simulationin practical design. Based on the description of model reduction theory andmethod in the view of mathematics, the advances of the reduced order modelsfor unsteady flow field were systematically introduced. The systemidentification based ROM such as Volterra/ROM, ARMA/ROM, Surrogate ROM, andflow eigen mode based ROM such as POD/ROM, HB/ROM, ND/ROM were reviewed. Theadvantages and drawbacks were analyzed with the possible direction of theirimprovements. The trends and prospects of the ROM for unsteady flow fieldwere discussed, with the indication that the next generation ROM will bemore robust and adaptive.

REVIEW ON IN-TUBE CONDENSATION IN DIFFERENT GRAVITY CONDITIONS

Jianfu Zhao, Hao Peng

2011, 41(6): 702-710. doi: 10.6052/1000-0992-2011-6-lxjzJ2010-081

Abstract(2374)

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Studies on horizontal in-tube condensation flow and heattransfer in different gravity conditions are reviewed, with focus concentrated on thecase of small scale tube, for low flow rate of ammonia, which is a routine practice inspace applications. Gravity influence on in-tube condensation in partialgravity conditions are discussed in detail. Condensate film on the innerperimeter in horizontal in-tube condensation leads to the differences of itsflow configuration from forced boiling and adiabatic two-phase gas-liquidflow, which enhances the effects of surface tension and increases the valueof the critical Bond number with regards to the transition to wavy andstratified flow regimes. Thus, the influence of gravity on flow and heattransfer in horizontal in-tube condensation with small scale tube and lowflow rate will be weakened, even be come negligible. It was found that themeasured frictional pressure drops in these cases are close to the predictionsgiven by smooth annular flow model, which are smaller than the predictions byempirical correlations based on the experimental data of two-phasegas-liquid flow at conventional conditions. Better predictions are obtainedonly by using a method based on a coupling of the void fraction with theinterfacial shear rate.

REVIEW AND PROSPECT OF RESEARCHES ON FLEXIBLE CURVED BEAM SYSTEMS

Keqi Pan, Jinyang Liu

2011, 41(6): 711-721. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-022

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This paper presents theoretical developments as well asengineering applications of the curved beam system. Firstly, the progress ofmodeling formulation for the dynamic analysis of flexible multi-body systemsis reviewed. Then, on the basis of the theory of continuum mechanics andmulti-body system dynamics, the description of strain-displacementrelationships including geometric nonlinearity is presented for the planar and the spatialcurved beams, respectively. The suitability of finite elementdiscretization methods for curved beams with constant or varied curvatureis summarized. The special difficulties related to modeling andcomputational methods for the flexible multi-body system are pointed outbased on previous researches, and, the advances in experimenttechniques for curved beam systems are also elucidated. Finally, the prospect for future investigations is suggested.

DNA SEQUENCING METHOD BASED ON ELECTRO-MECHANICAL EFFECTS BETWEEN\ DNA AND NANO-STRUCTURES

Zhenhai Li, Wei Yang

2011, 41(6): 722-729. doi: 10.6052/1000-0992-2011-6-lxjzJ2010-094

Abstract(2022)

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This review outlines two categories of recent developments in DNA sequencingmethods that are based upon electro-mechanical effects. These two methodsutilize the interactions between DNA and a nanopore, and between DNA and a carbonnanotube respectively. In this review, we describe the sequencing methodsassociated with these two nano-structures, including the structurefabrication, the interaction with DNA, the sequencing principle, and theresearch status.

THEORYOFDIELECTRIC ELASTOMERS

2011, 41(6): 730-750. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-021

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In response to a stimulus, a soft material deforms, and the deformation provides a function. We call such a material a soft active material (SAM). This review focuses on one class of soft active materials: dielectric elastomers. When a membrane of a dielectric elastomer is subject to a voltage through its thickness, the membrane reduces thickness and expands area, possibly straining over 100%. The dielectric elastomers are being developed as transducers for broad applications, including soft robots, adaptive optics, Braille displays, and electric generators. This paper reviews the theory of dielectric elastomers, developed within continuum mechanics and thermodynamics, and motivated by molecular pictures and empirical observations. The theory couples large deformation and electric potential, and describes nonlinear and nonequilibrium behavior, such as electromechanical instability and viscoelasticity. The theory enables the finite element method to simulate transducers of realistic configurations, predicts the efficiency of electromechanical energy conversion, and suggests alternative routes to achieve giant voltage-induced deformation. It is hoped that the theory will aid in the creation of materials and devices.

2011, 41(6): 751-756. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-165

Abstract(1778)

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THE 7TH NATIONAL WORKSHOP OF YOUNG SCHOLARS ON FLUID MECHANICS

Jiangfeng Wang, Panfeng Zhang, Shige Zhan

2011, 41(6): 757-759. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-146

Abstract(1508)

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REVIEW OF THE CHINESE CONFERENCE ON THEORETICAL AND APPLIED MECHANICS----- 2001 IN MEMORIAL OF TSIEN HSUE-SHEN'S 100 TH ANNIVERSARY

Zhengdao Wang, Baohua Ji, Jifu Zhou, Jianjun Tao, Liaoliang Ke, Weiqiu Chen, Yanan Tang, Shige Zhan, Yazheng Yang, Xiqiao Feng

2011, 41(6): 760-775. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-139

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REVIEW OF THE DRAG PREDICTION WORKSHOP SERIES

Chao Yan, Xi Ke, Wu Yuan, Jian Yu

2011, 41(6): 776-784. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-024

Abstract(2824)

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Verification and validation has been the key problem to the development of CFD. The AIAA CFD Drag Prediction Workshop (DPW) Series was an important academic activity concerning verification and validation of CFD, whose purpose is to provide an impartial international forum for evaluating the effectiveness of CFD Navier-Stokes solvers, and to assess state-of-the-art CFD methods as practical aerodynamic tools for the prediction of forces and moments on industry-relevant geometries. The results and conclusions of the four DPW series are summarized. Finally, some thoughts are put forward with respect to the development of CFD.

THE 7TH EUROPEAN NONLINEAR DYNAMICS CONFERENCE

Jian Xu, Hongbin Fang, Zaihua Wang, Qishao Lu

2011, 41(6): 785-786. doi: 10.6052/1000-0992-2011-6-lxjzJ2011-145

Abstract(2164)

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