“轨道力学”多媒体CAI课件的开发

本文分析了“轨道力学”传统教学过程中存在的问题，介绍了多媒体ＣＡＩ课件的结构及课件开发平台与媒体制作工具，并对课件的教学效果和在教学过程中所发挥的作用进行介绍．     

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以``流体力学实验助手'课件为例，介绍了数据输入与处理课件在流体 力学实验教学中的应用. 该课件作为流体力学实验课程的辅助教学工具，用于学生在实验结 束后当场输入和保存实验数据,教师对学生实验报告的批阅和讲评，以及学生对发回实验报告 的检查和核对. 该课件的使用，节省了教师批阅和讲评学生实验报告所费时间和精力，并为 学生核查实验报告计算或作图是否正确提供了方便.     

钢架雪车如何实现贴壁飞行

针对冬季奥运会的钢架雪车比赛项目,通过运用达朗贝尔原理,本文阐述了钢架雪车运动员在比赛过弯阶段实现贴壁“飞行”的力学原理,设计制作了实验道具并开展了演示实验,阐明了适当的滑行速度和低重心是钢架雪车运动员安全顺利过弯的重要因素。本文还讨论了本演示实验在理论力学教学中的应用前景。     

力学课程CAI各种模式的作用

最近几年来国内各高校有关的力学教师为力学课程教学内容和教学方法的改革,试探着开展了计算机辅助教学(CAI)的工作.这项工作已涉及到大部分的力学课程,各种模式的软件已在教学实践中初步使用.主要用在:教师备课或出题;课堂上的教学演示;部分学生课外复习、课外小组活动或有关的选修课等.实践说明了 CAI 对于提高教学质量和学习积极性、辅助课堂的教学具有积极作用,颇受学生的欢迎.值得 ...     

数值仿真在岩石力学教学中的应用

岩石力学作为一个重要的力学分支，是土木工程、水利水电、采矿工程等应用型学科的重要基础。本文首先调研了岩石力学教学中存在的难点，分析了数值仿真技术在教学中的优势。随后，以岩石单轴压缩实验为例，采用图像采集与颗粒流模拟相结合的数值仿真技术，演示了岩石瞬态破坏过程，揭示了岩石在受到外力时的破坏方式和破坏机理。表明了数值仿真技术在岩石力学教学中具有“全尺度、全维度、全时程”等优点。展示了数值仿真技术在描述岩石破坏过程中形象、直观的教学效果。     

核心通识课“无处不在的力学”的教学实践

力学通识教育对培养学生科学与工程素养具有重要意义。本文基于核心通识课“无处不在的力学”的多轮教学实践,对多学时条件下的力学通识课程的组织与实施进行了探索,建立形成了“学科规划、多人授课、专人负责”的通识课程管理模式、“价值引领、知识传授、能力培养”相融合的课程理念和“讲授式教学、研讨式教学、研究型教学”相结合的多元教学模式。课程开设以来,学生选课踊跃,教学团队投入度高,促进了学生科学与工程素养的提高,扩大了力学学科在师生中的影响。     

第五届全国中学生趣味力学制作邀请赛介绍

 2012 年11 月18 日, 第五届全国中学生趣味力学制作邀请赛在北京师范大学附属实验中学举行, 来自全国16 所中学的160 余名师生参加了本次活动. 北京科技视频网、中国科学报等媒体对本次活动进行了报道. 此次活动由中国力学学会主办, 北京师范大学附属实验中学协办, 比赛题目由高云峰设计.     

21世纪的实验力学

２１世纪的实验力学贾有权（天津大学力学系，天津３０００７２）看了“力学─—迎接２１世纪新的挑战”后，很受启发和鼓舞，心里有许多话要说，想来，还是先谈谈实验力学吧．“力学─—迎接２１世纪新的挑战”一文中，只提到实验是新现象的启示和理论的验证，这是不够的...     

跳台滑雪中运动员采用什么姿态飞得既稳且远

针对冰雪运动项目跳台滑雪,本文阐述了跳台滑雪运动员在比赛过程中助滑、起跳、飞行及着陆阶段的动作技术特点及其所蕴含的力学原理,设计制作了实验道具并开展了演示实验,说明了起跳阶段适当蹬地与飞行阶段维持特定姿态是跳台滑雪运动员取得优异成绩的关键因素。本文还探讨了相关演示实验在基础力学教学中的应用前景。     

新工科背景下基础力学实验教学模式改革实践与探索

针对“约定真值”的传统实验教学模式存在的判据模糊、内容固化和数据处理简单等不足,本文开展了“新工科”基础力学实验教学模式改革探索工作。通过调整教学观念、丰富实验内容和系统数据处理等方法,明确了基础力学实验判据,构建了以学生自主实践为中心,旨在培养实践创新能力、人文素养和家国情怀的力学实验教学新模式。     

一种基于直接计算高阶奇异积分的断裂力学双边界积分方程分析法

相对于有限元法,边界单元法在求解断裂问题上有着独特的优势,现有的边界单元法中主要有子区域法和双边界积分方程法.采用一种改进的双边界积分方程法求解二维、三维断裂问题的应力强度因子,对非裂纹边界采用传统的位移边界积分方程,只需对裂纹面中的一面采用面力边界积分方程,并以裂纹间断位移为未知量直接用于计算应力强度因子.采用一种高阶奇异积分的直接法计算面力边界积分方程中的超强奇异积分;对于裂纹尖端单元,提供了三种不同形式的间断位移插值函数,采用两点公式计算应力强度因子.给出了多个具体的算例,与现存的精确解或参考解对比,可得到高精度的计算结果.      

汶川地震诱发文家沟巨型滑坡 碎屑流基本特征及成因机制初步分析

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2008年5月12日,汶川M80地震在四川省绵竹市清平乡文家沟内诱发一巨型滑坡。通过现场调查得知,滑坡前后缘高差455m,厚度20～30m,滑面为基岩层面,初始方量2750×107m3。滑体在运动中转化为碎屑流。滑坡-碎屑流总的水平运动距离为4022m,垂直运动距离为1443m,遗留的堆积物体积达5×107m3。滑坡距映秀—北川断裂仅36km,位于其下盘,地震烈度达XI度。滑坡导致文家沟中48人遇害,并形成一条完整的地震次生地质灾害链。初步分析表明滑坡启动速度快,滑坡向碎屑流转化过程明显、地点明确。碎屑流运动过程复杂,伴有强烈的“气垫效应”和“前缘气浪冲击效应”。作者认为,文家沟滑坡的高启动速度是长持时强烈地震动作用的结果,与山体的猛烈碰撞是导致滑体解体并转化为碎屑流的原因。     

Preface: Orbits around asteroid

One of the core issues in modern celestial mechanics is the orbital dynamics in the near-regime gravitational field of as- teroids, which provides deep insights into the mathematical nature of a class of nonlinear systems, and plays as a critical basis for in situ explorations of different science goals. Lots of efforts have been made to reveal the characteristics of orbital motion in the vicinity of asteroids, and to improve the skills of asteroid research in methodology.     

Effet de l'anisotropie élastique cristalline sur la distribution des facteurs de Schmid à la surface des polycristauxInfluence of crystalline elasticity anisotropy on Schmid factor distribution at the free surface of polycrystals

Experimental studies of the plasticity mechanisms of polycrystals are usually based on the Schmid factor distribution supposing crystalline elasticity isotropy. A numerical evaluation of the effect of crystalline elasticity anisotropy on the apparent Schmid factor distribution at the free surface of polycrystals is presented. Cubic elasticity is considered. Order II stresses (averaged on all grains with the same crystallographic orientation) as well as variations between averages computed on grains with the same crystallographic orientation but with different neighbour grains are computed. The Finite Element Method is used. Commonly studied metals presenting an increasing anisotropy degree are considered (aluminium, nickel, austenite, copper). Concerning order II stresses in strongly anisotropic metals, the apparent Schmid factor distribution is drifted towards small Schmid factor values (the maximum Schmid factor is equal to 0.43 instead of 0.5) and the slip activation order between characteristic orientations of the crystallographic standard triangle is modified. The computed square deviations of the stresses averaged on grains with the same crystallographic orientation but with different neighbour grains are a bit higher than the second order ones (inter-orientation scatter). Our numerical evaluations agree quantitatively with several observations and measures of the literature concerning stress and strain distribution in copper and austenite polycrystals submitted to low amplitude loadings. Hopefully, the given apparent Schmid factor distributions could help to better understand the observations of the plasticity mechanisms taking place at the free surface of polycrystals. To cite this article: M. Sauzay, C. R. Mecanique 334 (2006).     

Nonlinear behavior of matrix-inclusion composites under high confining pressure: application to concrete and mortar

This paper is devoted to a micromechanics-based simulation of the response of concrete to hydrostatic and oedometric compressions. Concrete is described as a composite made up of a cement matrix in which rigid inclusions are embedded. The focus is put on the role of the interface between matrix and inclusion which represent the interfacial transition zone (ITZ). A plastic behavior is considered for both the matrix and the interfaces. The effective response of the composite is derived from the modified secant method adapted to the situation of imperfect interfaces. To cite this article: T.H. Le et al., C. R. Mecanique 336 (2008).     

Dynamics and Breakup of Viscoelastic Liquids (A Review)

The phenomena of hydrodynamic breakup of liquid jets, drops, films, bridges, and filaments are reviewed for liquids with viscoelastic properties. The reasons for breakup are capillary instabilities, collisions with rigid obstacles, and other forms of dynamic action. The relationship between the properties of the liquids and the features of the breakup process is discussed.     

Flow stability analysis and excitation using pulsating jets

Classical flow stability applied to transition from laminar to turbulent flow may also describe the behavior of vorticity fluctuations created by a pulsating jet placed along a solid boundary. A numerical laminar flow experiment involving a pulsating jet placed along the surface of a duct with flow separation downstream, resulted in eliminating most part of the separated flow region. Applying the same approach to a turbulent flow, it was possible to develop a turbulent stability flow formulation and apply successfully turbulent pulsating jet flow separation control. To cite this article: D. Skamnakis, K. Papailiou, C. R. Mecanique 333 (2005).