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2006, 36(1): 1-5. doi: 10.6052/1000-0992-2006-1-J2006-023

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2006, 36(1): 6-7. doi: 10.6052/1000-0992-2006-1-J2006-027

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2006, 36(1): 8-10. doi: 10.6052/1000-0992-2006-1-J2006-022

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2006, 36(1): 11-11. doi: 10.6052/1000-0992-2006-1-J2006-025

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2006, 36(1): 12-12. doi: 10.6052/1000-0992-2006-1-J2006-024

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2006, 36(1): 13-15. doi: 10.6052/1000-0992-2006-1-J2006-026

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2006, 36(1): 16-16. doi: 10.6052/1000-0992-2006-1-J2006-021

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ADVANCES IN DYNAMICS FOR DELAYED SYSTEMS

2006, 36(1): 17-30. doi: 10.6052/1000-0992-2006-1-J2005-095

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The studies from 1999 to now on dynamics of delayed systemsare reviewed in this paper. They concernmechanics, mechanical engineering, aeronautics and astronautics,ecology, biology, neural network, laser, electronics, informationtechnology, security communication, economics and so on. The typical methods and techniques are discaussed. It is shownthat the delayed systems are ubiquitous in nature and engineering. Many new problems and phenomena need to be studied and explored even for some simple and known oscillators when the effects of delays on systems are considered. Based on some existing problems in the studies, some topics for future studies are suggested, for examples, control strategies focused on delayed feedbacks, effects of combining delay with nonlinearities on systems, delay induced multiple bifurcations and complex dynamics in systems, computing models focused on net systems with delayed coupling of state variables and so on. These problems should be addressed since they do not occur in nonlinear systems without delays.

2006, 36(1): 31-35. doi: 10.6052/1000-0992-2006-1-J2005-061

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Similarity solutions of the Navier-Stokes equations arereviewed. It is shown that the method of stretching leads to all existing significant nonlinear solutions. The steady state solutions areeither inversely proportional or proportional to distance. The unsteadysolutions have a very specific time dependence.

FROM FE MODEL UPDATING TO MODEL VALIDATION:ADVANCES IN MODELING OF DYNAMIC STRUCTURES

2006, 36(1): 36-42. doi: 10.6052/1000-0992-2006-1-J2004-142

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The accuracy of a finite element model is important instructural dynamic predictions. The well-developed model updating techniqueaims to improve the accuracy of the prediction and is beginning to be used inindustry. But the model updating technique does not work well in cases with non-linearity or model uncertainties. The model validationproposed in the end of the 20th century is to see how accurately thecomputational models can represent the real world in a realistic way.In this paper, the model validation and its relevant issues arediscussed with respect to the model updating technique.

ADVANCES IN STRUCTURAL MECHANICS OF CHINESE ANCIENT ARCHITECTURES

2006, 36(1): 43-64. doi: 10.6052/1000-0992-2006-1-J2004-116

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Chinese ancient architectures are valuable heritage of ancient culture of China. Many historicalbuildings have been preserved up to now. The researches on the structural mechanics of ancient architectures show thedifferent aspects of mechanics. Systematical studies have been carrivedout inXi'an Jiaotong University since 1982. It is related with the need of repair of some national preservation relics in Xi'an.These studies include: 1, Ancient wooden structures including three nationalpreservation relics: Arrow Tower atNorth City Gate, City Tower at East City Gate in Xi'an and Baogao Temple at Ningbao. 2, Ancient tall masonrybuilding, the Big Goose Pagoda and Small Goose Pagoda in Xi'an. 3, Mechanical characteristics of ancient soilunder foundation and city wall; the influence of caves in and under theancient city wall on the stability of the wall; 4,The typical Chinese ancient building at the center of the city: the Bell Tower and Drum Tower. These researches alsoconcern the behavior of ``Dougong'' and Joggle joint of woodenstructures, foundation of pagoda; differentialsettlements of Arrow Tower and the resistance to earthquake of these historical architecture heritages. Some otherstudies are also introduced. This paper gives a summary of these researches.Preservation and research are nowadays an essential requirement for the famous monuments, buildings, towersand others. Our society is more and more conscious of this necessity, which involves increasing activities ofrestoration, and then sometimes also of repair, mechanical strengthening and seismic retrofitting. Many historicalbuildings have in fact problems of structural strength and stability;the need for further studies on structural mechanicsand materials is definitely growing.

FATIGUE LIFE EVALUATION UNDER MULTIAXIAL RANDOM LOADINGS

2006, 36(1): 65-74. doi: 10.6052/1000-0992-2006-1-J2004-131

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The componentsof engineering structures are usually subjected to a complex loading. It is not always safe if a uniaxial fatiguemodel is used for fatigue design of structures under multiaxial loading. Fatigue lifeprediction under multiaxial random loading has been under study recently. Inthe course of the fatigue life prediction under multiaxial random loading, cyclecounting is first to be considered. The rainflow counting method can be used to countthe cycles in the multiaxial loading. Cumulative fatigue damage analysis plays a keyrole in the life prediction of the components and the structures subjected to loadhistories. Since the linear damage rule was proposed, many damage models have beendeveloped. The fatigue damage due to random loadings can be determined bydifferent damage models.But none of them is universally accepted. The applicability of each model varies fromcase to case. The linear damage rule is still dominantly used in design, in spiteof its major shortcomings. The damage accumulation in two loading levels and modes,and the relationship between the damage and the physical mechanism are reviewed inthis paper. The fatigue life prediction models under multiaxial random loadingare reviewed in detail and the applicability of these models are discussed. Somesuggestions are made for future research.

TOPOLOGY EXTRACTION IN THE TOPOLOGY OPTIMIZATION DESIGN FOR STRUCTURES AND COMPLIANT MECHANISMS

2006, 36(1): 75-84. doi: 10.6052/1000-0992-2006-1-J2004-127

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It is important to extract useful topologiesfrom the solutions to the topology optimization design for structures andcompliant mechanisms. However, checkerboard patterns andintermediate elements in most topology results make a topologicalcontour extraction very difficult. Due to these facts, the elimination ofcheckerboard patterns, the acceptance or rejection of intermediateelements and thecontour extraction of the resultant topology are three mainproblems during the topology extraction process for structures and compliantmechanisms. The factors in forming checkerboard patterns and intermediateelements during the topology optimization process and the existing methods tocircumvent these problems are discussed. Three typical approaches for imageprocessing, those of level set, parametric active contour and edgedetection, are also discussed.

REVIEW ON THE PENETRATION/PERFORATION OF CERAMICS TARGETS

2006, 36(1): 85-102. doi: 10.6052/1000-0992-2006-1-J2004-086

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In the last decade, the dynamic response of ceramicmaterials and the penetration/perforation of targets of ceramics,ceramic/metal, ceramic/composite and layered ceramics is an activeresearch area. It has applications, especially, in the military field. Relatively little work in thisarea is conducted in China. The present paper introduces therecent advances in this area.Theexperimental techniques, penetration/perforation mechanisms and theoreticalmodels are reviewed. The cavity expansion model in ceramics penetration andthe effect of failure wave are specially addressed. Some research proposalsare made at the end of the paper.

A MECHANICS STUDY ON ADAPTIVENESS OF BIOLOGIC MORPHOLOGIES AND STRUCTURE AND ITS APPLICATIONS

2006, 36(1): 103-110. doi: 10.6052/1000-0992-2006-1-J2005-015

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Bymeans of the microstructures and morphologies of bone,bamboo and biologic branch systems in nature, the adaptiveness of thebiologic morphologies and structures is studied from the viewpoint ofmechanics. Some engineering applications are briefly introduced, such as self-healing materials onthe basis of the re-construction mechanism of bone, design methodologies ofstiffener distribution for thin plate structures and cooling channel layoutin the heat transfer systems on the basis of the growth mechanism of thebiologic branch systems. The engineeringmaterials and structures as well as their design methodologies based onthe growth mechanisms of the living things in nature can break through somelimits of the conventional products and methods. It can be said that thestudy on the relationship between the morphologies and materials of livingthings, and their functional performance and strengths, as well as theideal engineering materials and structural design methodologies, is avery important research topic.

ADVANCES IN INTERNAL WAVES DUE TO MOVING BODY IN STRATIFIED FLUID SYSTEMS

2006, 36(1): 111-124. doi: 10.6052/1000-0992-2006-1-J2005-006

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This article presents a brief review of the research workon both the Kelvin-wake and the non-Kelvin-wake generated by a submergedbody moving, respectively, in continuous and discontinuous densitystratification systems. The review lays its emphasis on analytical resultsand related experimental work in a stratified tank. The general governingequation for the non-Kelvin-wake in the continuously stratified fluid andthe potential-flow analysis for the Kelvin-wake in the discontinuouslystratified fluidare outlined. Three special internal waves, i.e., the precursor soliton,algebraic solitary wave and flat solitary wave, induced by a movingsource,are described, in which the internal flat solitary wave is shown to be atypical limiting solitary wave in experiments by the authors and then is firstformulated by a conjugate flow model. The complicated dynamicalcharacteristics in the internal wave generation due to a moving body inalinearly-distributed density fluid are summarized, including space-timestructures at near and far fields of wakes, instabilities, coupledconfigurations between vortex and turbulence and interactions betweeninternal wave and turbulence.

ADVANCES OF NUMERICAL METHODS FOR GENERAL DYNAMIC EQUATION DESCRIBING DISPERSED SYSTEM

2006, 36(1): 125-141. doi: 10.6052/1000-0992-2006-1-J2004-140

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The time evolution of particle size distribution (PSD)in dispersed systems is described by the General Dynamic Equation (GDE),taking accout of coagulation, breakage, condensation/evaporation, nucleation,deposition, etc. GDE is a typical partially integro-differentialequation.Consequently, normal numerical methods can hardly be used to solve it.The paper discusses the theoretical foundations, advantages anddisadvantages, and the recent development of some numerical methods for GDE,including the moments of method, sectional method, discrete method,discrete-sectional method, and Monte Carlo method. The paper paysspecial attention to the MonteCarlo method, including the ``time-driven'' Monte Carlo method, ``event-driven''Monte Carlo method, constant number method, constant volume method.

INFORMATION PRESERVATION (IP) METHOD IN SIMULATION OF INTERNAL RAREFIED GAS FLOWS IN MENS

2006, 36(1): 142-150. doi: 10.6052/1000-0992-2006-1-J2005-070

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This paper reviews firstly method for treating low speedrarefied gas flows: the linearized Boltzmann equation method , the LaticeBoltzmann method (LBM), the Navier-Stokes equation plus slipboundary conditions and the DSMC method, and discussed thedifficulties in simulating low speed transitional MEMS flows, especiallythe internal flows. In particular, the present version of the LBM is shownunfeasible for simulation of MEMS flow in transitional regime. Theinformation preservation (IP) method overcomes the difficulty of thestatistical simulation caused by the small information to noise ratio forlow speed flows by preserving the average information of the enormousnumber of molecules a simulated molecule represents. A kind ofvalidation is given in this paper. The specificities of the internal flows inMEMS, i. e. the low speed and the large length to width ratio, result inthe problem of elliptic nature of the necessity to regulate the inlet and theoutlet boundary conditions that influence each other. Through theexample of the IP calculation of the microchannel (thousandsmicrometers long) flow it is shown that the adoption of the conservativescheme of the mass conservation equation and the super relaxationmethod resolves this problem successfully. With employment of the samemeans the IP method solves the thin film air bearing problem intransitional regime for authentic hard disc write/read head length(L=1000 micrometers) and provides pressure distribution in fullagreement with the generalized Reynolds equation, while before this theDSMC check of the validity of the Reynolds equation was done only forshort (L=5 micrometers) drive head. The author suggests degenerate theReynolds equation to solve the microchannel flow problem in transitionalregime, thus provide a means with merit of strict kinetic theory for testingvarious methods intending to treat internal MEMS flows in transitionalregime.

2006, 36(1): 151-153. doi: 10.6052/1000-0992-2006-1-J2005-135

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2006, 36(1): 154-154. doi: 10.6052/1000-0992-2006-1-J2006-035

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2006, 36(1): 155-158. doi: 10.6052/1000-0992-2006-1-J2006-034

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2006, 36(1): 159-160. doi: 10.6052/1000-0992-2006-1-J2006-036

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2006 Vol. 36, No. 1

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