Cool,Dry, Nano-scale DIC Patterning of Delicate,Heterogeneous, Non-planar Specimens by Micro-mist Nebulization

Experimental Mechanics - Background: Application of patterns to enable high-resolution Digital Image Correlation (DIC) at the small scale (μm/nm) is known to be very challenging as techniques...     

硫代磷酸三正辛酯的合成及其摩擦学性能研究

合成了一统代及四硫代磷酸三正辛酯，用电感耦合等离子体原子发射光谱仪、质谱仪和傅立叶转换红外光谱仪等表征了所合成的一硫代及四硫代磷酸三正辛酯的组成和结构，并在四球摩擦磨损试验机上考察了其在液体石蜡中的摩擦学性能；用扫描电子显微镜和X射线光电子能谱仪对钢球磨痕表面进行了分析表征。结果表明：所合成的一硫代磷酸酯具有比二烷基二硫代磷酸锌更优异的摩擦学性能，可以显著提高液体石蜡的承载能力和抗磨能力，并能在适当浓度和较高载荷（≥400N）下改善液体石蜡的减摩性能；而活性元素含量较高的四硫代磷酸酯对液体石蜡的极压、抗磨和减摩性能的影响不大，这可能是由于其导致腐蚀磨损所致，磨损表面分析结果表明，含添加剂的石蜡油在摩擦过程中发生腐蚀磨损，主要形成了由物理吸附膜和摩擦化学反应膜组成的复合膜。     

Damping Properties of Sequoia, Birch, Pine, and Aspen under Shock Loading

Results of an experimental study of strength—deformation properties of sequoia, aspen, pine, and birch wood for various loading rates, temperatures, humidities, and orientation angles of wood fibers with respect to the loading direction are described. Stress—strain diagrams and an analytical dependence of strength on humidity, temperature, and loading rate are presented.     

无处不在的力学,众说纷纭的力学,魅力无穷的力学——漫评《院士谈力学》

正进入力学界近三十年的一对中年伉俪两年前突发奇想,想要知道:力学界的两院院士关于力学都说了些什么?于是,利用20个月的业余时间,孜孜矻矻,探微索隐,精心编纂,推出了这本62万字的《院士谈力学》[1].此书今年10月上网发行,不久即告售罄,坊间好评不绝于耳.为什么这本大部头科普著作如此受欢迎?且听笔者慢慢道来.1无处不在的力学这是因为力学无处不在.正如郑哲敏院士为该书所写的序言中所说:"力     

Stability,buckling, and postbuckling of elastic structures

Summary This paper is the continuation of a research on the stability and postbuckling behaviour of elastic structures; in the first Part [n. 4, Vol. X, 1975 of this Journal], the potential energy of elastic tridimensional bodies has been defined in a suitable configuration space, and its properties of regularity have been studied. According to the program given in the previous Paper, we examine now the potential energy functional for some monodimensional and bidimensional structural models. Then the Part II of this research is developed so that the Liapunov stability of the equilibrium configuration of continuous elastic structures is analyzed by means of suitable energy criteria.

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Sommario Questo lavoro costituisce il proseguimento di uno studio sulle stabilità e comportamento postcritico delle strutture elastiche; nel precedente lavoro, pubblicato sul n. 4, vol. X, 1975 di questa rivista, è stato esaminato il problema della definizione dell'energia potenziale di un corpo elastico tridimensionale in un opportuno spazio funzionale delle configurazioni, e sono state esaminate le proprietà di regolarità di questo funzionale. Proseguendo il programma formulato nel lavoro precedente, viene ora innanzitutto completato lo studio del funzionale energia potenziale con riferimento a modelli strutturali mono e bidimensionali. Viene poi sviluppata la Parte II e cioè l'analisi della stabilità secondo Liapunov di una configurazione di equilibrio attraverso opportune formulazioni dei criteri dell'energia.

     

Natural vibrations of orthotropic,ribbed, cylindrical shells

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 27, No. 10, pp. 83–90, October, 1991.     

Rotation,collapse, and scattering of point vortices

Relative equilibria, collapse, and scattering of point vortices in the plane are studied. Vortex systems with arbitrary choice of circulations are considered. An ordinary differential equation satisfied by polynomials with roots at the vortex positions is found. Explicit expressions for vortex double-ring configurations in the cases of two regular polygons, three regular polygons, and a quadrangle with a digon are obtained.     

Extended thermodynamics, viscoelasticity, and strain of solids

In this paper will be presented a formulation of extended thermodynamics for viscoelastic materials with heat conduction. The application of the Galilean invariance of the balance equations and the principle of entropy lead to the introduction of Lagrange multipliers, which provide constitutive equations for the flows. A condition of hyperbolicity system of equations is achieved by the concavity of the entropy density. The balance equations are linearized.