On elastocapillarity: A review

Elastocapillary phenomena involving elastic deformation of solid structures coupled with capillary effects of liquid droplets/films can be observed in a diversity of fields,e.g.,biology and microelectromechanical systems(MEMS).Understanding the physical mechanisms underlying these phenomena is of great interest for the design of new materials and devices by utilizing the effects of surface tension at micro and nano scales.In this paper,some recent developments in the investigations on elastocapillary phenomena are briefly reviewed.Especially,we consider the deformation,adhesion,self-assembly,buckling and wrinkling of materials and devices induced by surface tensions or capillary forces.The main attention is paid to the experimental results of these phenomena and the theoretical analysis methods based on continuum mechanics.Additionally,the applications of these studies in the fields of MEMS,micro/nanometrology,and biomimetic design of advanced materials and devices are discussed.     

THE INTERACTION OF PLANE SH－WAVES AND CIRCULAR CAVITY SURFACED WITH LINING IN ANISOTBOPIC MEDIA

ＴＨＥＩＮＴＥＲＡＣＴＩＯＮＯＦＰＬＡＮＥＳＨ－ＷＡＶＥＳＡＮＤＣＩＲＣＵＬＡＲＣＡＶＩＴＹＳＵＲＦＡＣＥＤＷＩＴＨＬＩＮＩＮＧＩＮＡＮＩＳＯＴＢＯＰＩＣＭＥＤＩＡＨａｎＦｅｎｇ（韩峰）Ｗｅｉｙａｎｇ（韦扬）ＬｉｕＤｉａｎｋｕｉ（刘殿魁）（Ｒｅｃｅｉ...     

弹塑性岩土介质中渗透固结问题的参数二次规划法

岩土类介质在承受荷载时,不仅产生弹塑性变形,还伴随着渗流和固结,是一个关于时间的动态过程。本文建立起处理该问题的参变量变分原理以及相应的有限元方法,这样将原问题化为求解带约束条件(本构状态方程)的二次规划问题.文中讨论了单元的选取形式及具体的实施过程,还给出了一个实例.     

Steady rotation of a composite sphere in a concentric spherical cavity

The problem of steady rotation of a compositesphere located at the centre of a spherical container has beeninvestigated.A composite particle referred to in this paperis a spherical solid core covered with a permeable sphericalshell.The Brinkman’s model for the flow inside the composite sphere and the Stokes equation for the flow in the spherical container were used to study the motion.The torque experienced by the porous spherical particle in the presence ofcavity is obtained.The wall correction factor is calculated.In the limiting cases,the analytical solution describing thetorque for a porous sphere and for a solid sphere in an unbounded medium are obtained from the present analysis.     

A mixed method for the creep of a skin layer

ＡＭＩＸＥＤＭＥＴＨＯＤＦＯＲＴＨＥＣＲＥＥＰＯＦＡＳＫＩＮＬＡＹＥＲＨｕａｎｇＬｉ－ｄｕ（黄立独）ＷａｎｇＱｉｎ－ｑｕｅ（汪勤悫）（ＳｈａｎｇｈａｉＵｎｉｖｅｒｓｉｔｙ,Ｓｈａｎｇｈａｉ）ＭａｋＦａｋ－ｔａｔＡｒｔｈｕｒ（麦福达）（ＨｏｎｇＫｏｎｇ...     

Analysis of Stability on Elastic Plates with Initial Imperfections

ＡＮＡＬＹＳＩＳＯＦＳＴＡＢＩＬＩＴＹＯＮＥＬＡＳＴＩＣＰＬＡＴＥＳＷＩＴＨＩＮＩＴＩＡＬＩＭＰＥＲＦＥＣＴＩＯＮＳＸｕＫａｉｙｕ（徐凯宇）（ＲｅｃｅｉｖｅｄＯｃｔ．５．１９９４；ＣｏｍｍｕｎｉｃａｔｅｄＰａｉＬｉｚｈｏｕ）ＡＮＡＬＹＳＩＳＯＦＳＴＡ...     

Wind induced deformation and vibration of a Platanus acerifolia leaf

Deformation and vibration of twig-connected single leaf in wind is investigated experimentally.Results showthat the Reynolds number based on wind speed and lengthof leaf blade is a key parameter to the aerodynamic problem.In case the front surface facing the wind and with an increase of Reynolds number,the leaf experiences static deformation,large amplitude and low frequency sway,reconfiguration to delta wing shape,flapping of tips,high frequencyvibration of whole leaf blade,recovery of delta wing shape,and twig-leaf coupling vibration.Abrupt changes from onestate to another occur at critical Reynolds numbers.In casethe back surface facing the wind,the large amplitude andlow frequency sway does not occur,the recovered delta wingshape is replaced by a conic shape,and the critical Reynoldsnumbers of vibrations are higher than the ones corresponding to the case with the front surface facing the wind.Apair of ram-horn vortex is observed behind the delta wingshaped leaf.A single vortex is found downstream of theconic shaped leaf.A lift is induced by the vortex,and thislift helps leaf to adjust position and posture,stabilize bladedistortion and reduce drag and vibration.     

An example of PDE with two attractors

ＡＮＥＸＡＭＰＬＥＯＦＰＤＥＷＩＴＨＴＷＯＡＴＴＲＡＣＴＯＲＳＷａｎｇＧｕａｎｘｉａｎｇ（王冠香）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ,ＳｕｚｈｏｕＵｎｉｖｅｒｓｉｔｙ,Ｓｕｚｈｏｕ２１５００６Ｐ．Ｒ．Ｃｈｉｎａ）ＸｕＺｈｅｎｙｕａｎ（徐...     

THE GENERAL PROPERTIES OF THE SPHERICAL VORTICES（SV）OF n－TH ORDER AND THE CHAOTIC PHENOMENA AND OF THE ORDERED STRUCTURES OF THE SV OF 3RD ORDER

ＴＨＥＧＥＮＥＲＡＬＰＲＯＰＥＲＴＩＥＳＯＦＴＨＥＳＰＨＥＲＩＣＡＬＶＯＲＴＩＣＥＳ（ＳＶ）ＯＦｎ－ＴＨＯＲＤＥＲＡＮＤＴＨＥＣＨＡＯＴＩＣＰＨＥＮＯＭＥＮＡＡＮＤＯＦＴＨＥＯＲＤＥＲＥＤＳＴＲＵＣＴＵＲＥＳＯＦＴＨＥＳＶＯＦ３ＲＤＯＲＤＥＲＳｈｉＣ...     

多孔颗粒火药床燃烧转爆轰的敏感性研究

本文以不同粒度硝胺火药RDU-4,硝胺火药RPB,3/1-S为研究对象,探讨了多孔颗粒火药床燃烧转爆轰的敏感性。研究结果表明,火药颗粒尺寸越小,硝胺火药燃烧转爆轰越易实现:硝基胍组分具有抑制燃烧转冲击的作用,就同一装填条件下燃烧转冲击的难易而言,以RPB最易,3/1-S次之,RDU-4最难     

Free vibration and stability of moderate-thick cantilever plates

ＦＲＥＥＶＩＢＲＡＴＩＯＮＡＮＤＳＴＡＢＩＬＩＴＹＯＦＭＯＤＥＲＡＴＥ－ＴＨＩＣＫＣＡＮＴＩＬＥＶＥＲＰＬＡＴＥＳＺｈａｎｇＹｉｎ－ｙｉ（张音翼）（ＩｎｓｔｉｔｕｔｅｏｆＥｎｇｉｎｅｅｒｉｎｇＭｅｃｈａｎｉ,ＮａｎｃｈａｎｇＵｎｉｖｅｒｓｉｔｙ,Ｎａ...     

Experimental and simulation optimization analysis of the Whipple shields against shaped charge

Occasionally,the Whipple shields are used for the protection of a space station and a satellite against the meteoroids and orbital debris.In the Whipple shields each layer of the shield depletes part of high speed projectile energy either by breaking the projectile or absorbing its energy.Similarly,this investigation uses the Whipple shields against the shaped charge to protect the light armour such as infantry fighting vehicles with a little modification in their design.The unsteady multiple interactions of shaped charge jet with the Whipple shield package against the steady homogeneous target is scrutinized to optimize the shield thickness.Simulations indicate that the shield thickness of 0.75 mm offers an optimum configuration against the shaped charge.Experiments also support this evidence.     

Axial vibration analysis of nanocones based on nonlocal elasticity theory

Carbon nanocones have quite fascinating electronic and structural properties,whose axial vibration is seldom investigated in previous studies.In this paper,based ona nonlocal elasticity theory,a nonuniform rod model is applied to investigate the small-scale effect and the nonuniformeffect on axial vibration of nanocones.Using the modifiedWentzel-Brillouin-Kramers(WBK) method,an asymptoticsolution is obtained for the axial vibration of general nonuniform nanorods.Then,using similar procedure,the axial vibration of nanocones is analyzed for nonuniform parameters,mode number and nonlocal parameters.Explicit expressionsare derived for mode frequencies of clamped-clamped andclamped-free boundary conditions.It is found that axial vibration frequencies are highly overestimated by the classicalrod model because of ignorance of the effect of small lengthscale.     

Bending integral expressions of a cylinder with cracks

ＢＥＮＤＩＮＧＩＮＴＥＧＲＡＬＥＸＰＲＥＳＳＩＯＮＳＯＦＡＣＹＬＩＮＤＥＲＷＩＴＨＣＲＡＣＫＳＷａｎｇＸｉａｏ－ｃｈｕｎ（王晓春）（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃｓ,ＰｅｋｉｎｇＵｎｉｖｅｒｓｉｔｙ,Ｂｅｉｊｉｎｇ）（ＲｅｃｅｉｖｅｄＮｏｔ...     

CENTRIFUGAL INERTIA EFFECTS OF THE FLUID FLOW BETWEEN STEPPED SPHERICAL SURFACES

ＣＥＮＴＲＩＦＵＧＡＬＩＮＥＲＴＩＡＥＦＦＥＣＴＳＯＦＴＨＥＦＬＵＩＤＦＬＯＷＢＥＴＷＥＥＮＳＴＥＰＰＥＤＳＰＨＥＲＩＣＡＬＳＵＲＦＡＣＥＳＬｉｕＺｈｉｅｎ－ｂｅｉ（刘震北）（ＨａｒｈｉｎＩｎｓｔｉｔｕｔｅｏｆｔｅｃｈｎｏｌｏｇｙ．Ｈａｒｂｉｎ）（Ｒ...     

Influences of oscillatory structural forces on dewetting of nanoparticle-laden ultra-thin films

To understand the influences of nanoparticleson dewetting in ultra-thin films,both linear stability theory and numerical simulations are performed in the presentstudy,with the consideration of oscillatory structural(OS)forces.Long scale approximation is utilized to simplify thehydrodynamic and diffusion equations to a nonlinear systemfor film thickness and nanoparticle concentration.Resultsshow that the presence of nanoparticles generally suppressesthe dewetting process.Two physical mechanisms responsible for this phenomenon are addressed in the present study.When the oscillatory structural forces are relatively smaller,the essential feature of film evolution is similar to the case ofparticle-free flow.The reduction of the linear growth rate andthe postponement of film rupturing can be attributed to theincrement of the viscosity due to the presence of nanoparticles.On the other hand,when the intensity of the OS forcesbecomes stronger,the stepwise thinning of film can be observed which prevents the film from rupture.Numerical simulations indicate that this phenomenon is caused by the existence of a stable zone due to the oscillatory nature of thestructural forces.Another interesting finding is that the nonuniformity of the distribution of nanoparticle concentrationmight destabilize a spinodally stable film,and trigger the occurrence of film dewetting.     

Modeling rock failure using the numerical manifold method followed by the discontinuous deformation analysis

A complete rock failure process usually involvesopening/sliding of preexisting discontinuities as well as fracturing in intact rock bridges to form persistent failure surfaces and subsequent motions of the generated rock blocksThe recently developed numerical manifold method(NMM)has potential for modelling such a complete failure processHowever,the NMM suffers one limitation,i.e.,unexpectedmaterial domain area change occurs in rotation modellingThis problem can not be easily solved because the rigidbody rotation is not represented explicitly in the NMM.Thediscontinuous deformation analysis(DDA) is specially developed for modelling discrete block systems.The rotationinduced material area change in the DDA modelling canbe avoided conveniently because the rigid body rotation isrepresented in an explicit form.In this paper,a transitiontechnique is proposed and implemented to convert a NMMmodelling to a DDA modelling so as to simulate a completerock failure process entirely by means of the two methods,in which the NMM is adopted to model the early fracturingas well as the transition from continua to discontinua,whilethe DDA is adopted to model the subsequent motion of thegenerated rock blocks.Such a numerical approach also improves the simulation efficiency greatly as compared with acomplete NMM modelling approach.The fracturing of arock slab with pre-existing non-persistent joints located ona slope crest and the induced rockfall process are simulated.The validity of the modelling transition from the NMM tothe DDA is verified and the applicability of the proposed numerical approach is investigated.     

INVARIANT MANIFOLDS AND THEIR STABILITY IN A THREE－DIMENSIONAL MEASURE－PRESERVING MAPPING SYSTEMS

ＩＮＶＡＲＩＡＮＴＭＡＮＩＦＯＬＤＳＡＮＤＴＨＥＩＲＳＴＡＢＩＬＩＴＹＩＮＡＴＨＲＥＥ－ＤＩＭＥＮＳＩＯＮＡＬＭＥＡＳＵＲＥ－ＰＲＥＳＥＲＶＩＮＧＭＡＰＰＩＮＧＳＹＳＴＥＭＳＬｉｕＪｉｅ（刘杰）（ＲｅｃｅｉｖｅｄＤｅｃ．１．１９９４;Ｃｏｍｍｕｎｉｃ...     

Ⅰ型焦散线图象的微机自动处理

根据焦散线的原理,分析了Ⅰ型焦散线实验图象的特点,提出确定图像中焦散线位置的准则。基于此准则的微机图象处理,可自动精确测量Ⅰ型焦散线的最大直径。     

Experimental investigation on flow modes of electrospinning

Electrospinning experiments are performed byusing a set of experimental apparatus,a stroboscopic systemis adopted for capturing instantaneous images of the conejet configuration.The cone and the jet of aqueous solutionsof polyethylene oxide(PEO) are formed from an orifice of acapillary tube under the electric field.The viscoelastic constitutive relationship of the PEO solution is measured anddiscussed.The phenomena owing to the jet instability aredescribed,five flow modes and corresponding structures areobtained with variations of the fluid flow rate Q,the electricpotential U and the distance h from the orifice of the capillary tube to the collector.The flow modes of the cone-jetconfiguration involves the steady bending mode,the rotating bending mode,the swinging rotating mode,the blurringbending mode and the branching mode.Regimes in the Q-Uplane of the flow modes are also obtained.These results mayprovide the fundamentals to predict the operating conditionsexpected in practical applications.