力学进展

2008, 38(4): 393-426. doi: 10.6052/1000-0992-2008-4-J2007-137

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Due to the importance in clinical and cosmetic applications, the mechanical properties of skin tissue in vivo and in vitro have been studied extensively. In this paper, we present a comprehensive review on the recent developments of skin mechanics. The methods and apparatus of experiments in vivo and in vitro are summarized. The main mechanical properties and their anisotropy are reviewed, which includes Young's modulus, Poisson ratio, compressibility, strength, toughness, initial stress/tension, thermal expansion coefficient, binding force/delamination energy, and skin friction coefficient. Data from the literature are grouped and tabulated. Finally, future research directions in special areas are discussed.

STRUCTURAL RELIABILITY DESIGN UNDER INCOMPLETE INFORMATION

Chen Jianqiao

2008, 38(4): 427-436. doi: 10.6052/1000-0992-2008-4-J2007-040

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Conventionalreliability analysis is based on the probabilistic distribution ofrandom variables. In structural design problems, however,statistical data regarding load or resistance are usuallyincomplete. In addition, a robust structural design must considerthe interaction of the structures with the environment, errors inthe stage of the structure design, the structure analysis, theevaluation, and the fabrication, some of which may not becategorized as to randomness. Therefore, a new theoreticalframework for the structural reliability and the optimal designwhich incorporates the different uncertainty sources becomesnecessary to achieve a suitable practical solution different fromthe traditional probabilistic method. This paper provides anoverview on structural reliability and optimal design undercircumstances of incomplete information. Several topics such asprobability-based design, possibility theory for dealing withincomplete information, the influence of model errors andsubjective uncertainties, and applications of evolutionaryalgorithms to reliability design are discussed. The paperconcludes with a brief perspective for further research.

EXPERIMENTAL STUDY ON INTERFACE STRENGTH OF MICRO/NANO-MATERIALS AND THEIR STRUCTURES

SHANG Fulin

2008, 38(4): 437-452. doi: 10.6052/1000-0992-2008-4-J2007-082

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This paper reviewsrecent advances in experimental studies on mechanical strength ofsmall materials with micro- to nano-meter scales. In particular,experimental systems and some testing methods developed by thecurrent authors are introduced for measuring the interfacestrength in small materials and low-dimensional tiny components,and main experimental results are presented as well. The testingmethods discussed are: (1) sandwiched cantilever method forevaluating the initiation strength of an interface crack insubmicron films deposited on substrates, (2) modified AFM methodfor measuring the interface bonding strength between nano-islandsand substrates, (3) pre-cracking technique for measuring crackgrowth along the interface, (4) a crack initiation method fornano-components using special loading apparatus built in a TEM andcapable of in-situ observing the process of crack growth, (5)modified four-point bend method for measuring sub-critical crackgrowth along an interface between submicron films under fatigue,and (6) a special testing method for creep crack growth along aninterface between polymeric film and glass substrate. From theresults obtained, the authors pointed out the merits of the aboveexperimental methods and their limitations. Meanwhile, the mainchallenges and difficulties in testing the interface strength ofmicro- to nano-materials and such tiny structures aredemonstrated, and several future research topics are outlined.

EXPERIMENTAL INVESTIGATION ON FRACTURE BEHAVIOR OF FUNCTIONALLY GRADED MATERIALS

JIN Xin

2008, 38(4): 453-469. doi: 10.6052/1000-0992-2008-4-J2007-055

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Functionally gradedmaterials (FGMs) as a new kind of engineering materials has beendeveloped and used in various fields. The fracture of FGMs is anopen problem in materials science and solid mechanics. Althoughextensive researches on this topic have been made by theoreticaland numerical methods, there are only a few experimental works ininvestigating the fracture of FGMs, of which most are focused onmacro-toughness of FGMs but micro-mechanics of fracture. In thispaper, a brief introduction of experimental methods is presented.Recent advances of relative experimental works and results arereviewed and discussed. Finally, the drawbacks of the recentexperimental works are pointed out, and keystones of the furtherexperimental works are advanced.

DEVELOPMENT AND PROSPECTS OF NUMERICAL SIMULATION METHODS IN BODY FLUID FLOW IN VESSELS

2008, 38(4): 470-483. doi: 10.6052/1000-0992-2008-4-J2007-044

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Numerical simulationsof computational fluid dynamics have been successfully applied inmany branches of science and engineering since 1960s. Till about1980s, there had existed a large number of numericalinvestigations on fluid flows in blood vessels, tracheas and bileducts by using computer techniques. Researches in the latestdecade have been more related to clinical applications, analysisof organic functions and pathology. Practical images onpathological analysis and clinical treatments have been obtainedon complex flows in cerebral vessels, carotid arteries and cardiovessels, and on activities of alveolus. In 21st Century,computational fluid dynamics on human-body fluid flow will makemore advancement and have manifold applications in exploring thenature and human being. The present paper reviews the developmentsand achievements on computational fluid dynamics on human-bodyfluid flow. We hope it can draw more attentions for the researcharea and put the research forward.

ADVANCES IN RESEARCHES OF THE MECHANICAL BEHAVIORS OF BEDDED SALT ROCKS

2008, 38(4): 484-494. doi: 10.6052/1000-0992-2008-4-J2007-060

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The engineeringmechanical properties of bedded salt rocks are investigated forthe purpose of understanding energy storage in a deeply beddedsalt rocks formation. Compression tests show that the presence ofanhydrite interlayers affects strongly the deformation and failureof the bedded salt rocks. A `stress drop' phenomenon ofstress-strain curves is observed in low confining pressure casesand it denotes that the anhydrite layers fracture prior to thesalt rocks. Creep tests on the salt rocks, the anhydrites and thecomposite rocks imply that creep deformation of surrounding rocksof a storage cavern is controlled by the salt rock layer, andlong-term volume shrinkage is restricted by the anhydrite layers.Direct shear tests, Brazilian disk tests and TEM tests are carriedout to investigate the mechanical properties of the interfacesbetween the anhydrites and the salt rocks. These experiments showthat the interfaces are bonded perfectly and are strong, whichresults in good sealability and stability of the energy storagecaverns in the bedded salt rocks. Also in this paper, the Cosseratconstitutive theory is extended in special cases and is applied tostability analyses of the salt caverns in the bedded salt rockformation. Finally, several important future research directionson the mechanical properties of the bedded salt rocks are pointedout.

THE MECHANICS OF CYTOKINESIS AND MOLECULAR MECHANISM

2008, 38(4): 495-501. doi: 10.6052/1000-0992-2008-4-J2007-117

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Cytokinesis, themechanical separation of a mother cell into two daughter cells,occurs through a series of stereotypical shape changes.Cytokinesis is accompanied by mechanical phenomena through almostevery level. The formation of cortical subdomains with differentstiffness and viscoelasticity is critical for the resulting cellshape change. The recruitment of specific actin cross-linkingproteins is important for the local change of the stiffness. It isessential to understand fully the process of cells changing theirshapes, the cellular material properties achieving successfulcytokinesis, and the basis of molecular biology of cytokinesis. Inthis review, the mechanical properties of cells, the mechanics ofcytokinesis, and the molecular biology basis of cytokinesis arediscussed.

MODELING OF ELASTIC, THERMAL AND STRENGTH/FAILURE ANALYSIS OF TWO-DIMENSIONAL WOVEN COMPOSITES ------ A REVIEW

2008, 38(4): 502-517. doi: 10.6052/1000-0992-2008-4-J2007-107

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The usage of textilestructures as a reinforcement for polymer composites became essen-tial in many industrial applications in, for example, the marineand aerospace industries because of their favorable stiffness andstrength to weight ratio. Determination of elastic properties andfailure behavior of textile reinforced composites is vital forindustrial design and engineering applications. This paper aims topresent a review of numerical and analytical models for elastic,thermal, and strength/failure analysis of 2D reinforced wovencomposites. Major modeling techniques and approaches arepresented. A state of the art review of woven fabric composites ispresented starting from earlier one- dimensional models to recentthree-dimensional models. The intention is not to give a detailedanalysis of the mathematical approaches to the models discussed,but rather to inform researchers about the main ideas of previousworks. This review article cites 122 references.

2008, 38(4): 518-520. doi: 10.6052/1000-0992-2008-4-J2008-099

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