材料力学教学内容更新浅见

材料力学教学内容更新浅见肖锡玉,刘大泉（国防科学技术大学长沙４１００７３）现代科学技术的飞速发展使各传统学科之间交叉渗透、分化综合,形成一些新兴学科领域,原有的单一学科的概念逐步发展为学科群的概念．因此,高等院校的课程设置和教学内容必须随之加以改革、...     

材料力学教学内容改革的研究与实践

提出一种材料力学教学内容改革的方法,介绍了该方法的运用效果.     

面向21世纪材料力学教学的几点思考

面向２１世纪材料力学教学的几点思考郝松林刘大泉萧锡玉（国防科学技术大学，长沙４１００７３）讨论面向２１世纪的材料力学问题时，首先要问我国２１世纪需要什么样的人才？当然是要德、智、体全面发展的、会分析、能综合、敢于开拓的大学生，冯元桢先生在他著作［９］...     

材料力学实验教学改革的实践

利用实验室现有条件,拓展材料力学实验设备功能,提高教学效果,我们做了尝试,取得了一些经验．     

关于材料力学实验教学改革的设想

针对现行材料力学实验教学模式的弊端，根据多年来实验教学的体会，提出改革材料力学实验教学的几种新模式，以期提高实验教学质量．     

材料力学教材编写中几个问题的探讨

材料力学作为机械类、近机械类和土木工程类等专业主要必修课程之一,将为一系列后续课程的学习打下重要基础. 在总结了当前材料力学教材编写的基本情况后,重点对教材体系、应力集中和圣维南原理、应力状态、组合变形等教材内容编写中存在的问题及改进措施进行了探讨,为材料力学教材的编写或改版提供了一定的参考.     

《材料力学》教学中的几个实例

《材料力学》教学中的几个实例方德平（华侨大学土木工程系,泉州３６２０１１）《材料力学》的公式较多,推导过程也较复杂,部分学生对此敬而远之,不易从力学理论本身建立起力学概念．笔者从事教学多年,收集总结了一些讲课实例．这些实例通俗生动,一则可活跃课堂气氛...     

材料力学中的两个误差问题

材料力学中的两个误差问题吴国胜（金川有色金属公司职工大学，甘肃金昌市７３７１０３）１第一个误差问题即用薄壁圆筒扭转剪应力公式计算回轴扭转最大剪应力的相对误差及其最大值．薄壁圆筒弹性扭转时，在其任一横截面上存在垂直于半径的，沿周向大小不变、径向均匀分布...     

基于在线课程的材料力学疲劳问题教学内容拓展

随着网络化的发展,在线课程平台正起着举足轻重的作用。在课程学时被大量压缩的情况下,基于在线课程平台,以扩展阅读的形式对书本知识 进行拓展正受到广泛重视。本文以工科专业重要学习内容——疲劳问题为例,基于在线课程平台将教材中金属材料在稳定交变载荷下的疲劳问 题,拓展到不稳定载荷下金属材料疲劳及非金属材料的疲劳问题,并通过实例给出疲劳寿命估算公式。利用在线平台整合资源、拓展知识,对培 养学生分析和解决问题能力具有重要作用。     

Some half-space problems of cubic piezoelectric materials

Half-space problems of a cubic piezoelectric material subjected to anti-plane deformation and in-plane electric field are studied. A general solution in terms of the integration of the boundary data prescribed over the surface of the semi-infinite domain is derived. Based on the general solution, the problem of a concentrated line force acting on the surface is treated and ensuing electromechanical response is determined. The solution to the problem of a screw dislocation in the half-space is also obtained, and the result is exploited to study a sub-surface crack problem by simulating the crack as a continuous distribution of dislocations.     

Some problems in plane thermopiezoelectric materials with holes

Piezoelectric materials have recently attracted considerable attention due to their potential use in intelligent structural systems. In this paper, we treat the plane problem of thermopiezoelasticity with various holes and subject to coupled mechanical, electric and thermal loads. An analytical solution is obtained by applying the technique of conformal mapping and some identities in the Stroh formalism. The solution has a simple unified form for various holes such as ellipse, circle, triangle and square. By way of the solution, the expressions for the energy release rate and stress intensity factors of cracks are presented. Numerical results for concentration coefficients of stress and electric displacement along the hole boundary are given to assess the acceptability of the proposed method.     

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 结合笔者十多年来承担本科结构力学等课程教学工作的体会,就力学课程研究型教学中 基础知识的地位问题、学生应用技能和创新能力的培养问题、以及研讨课对提高教学质量的 作用等问题,谈了笔者的几点感想.     

用LS-DYNA辅助《材料力学》冲击问题的教学

利用显式动力分析软件LS-DYNA对小球自由落体冲击简支梁进行了数值模拟,得到了梁的位移和应力的时程曲线. 将模拟结果与《材料力学》教材中广泛采用的冲击问题简化解法的结果进行了对比. 通过观察时程曲线和冲击动画过程,可使学生对冲击问题有较深入的理解.     

《材料力学》多媒体仿真教学实验系统

为解决当前材料力学实验教学的困境,本文从依靠计算机辅助教学这一教学手段出发,探索并开发出一个基于模拟仿真的材料力学实验教学系统,并介绍了它的设计思路和该系统的特点.     

Some basic problems in numerically simulating effective properties and local fields of composite materials

It is pointed out that to numerically estimate the effective properties and local fields of matrix-inclusion composites, a commonly adopted method is accompanied with some serious draw-backs. We call this method the nominal loading scheme (NLS), which considers the actual inclusion distribution inside a finite domain, Ω say, treats the external domain of Ω to be of the pure matrix material, and imposes the actural traction, σ^∞ say on the remote boundary. It thus gives rise to the following basic problems: (i) Can NLS be improved remarkably just by adjusting σ^∞? (ii) What is the relationship between the size of Ω and the scale of inclusions? (iii) Which choice is better in calculating the effective properties, the whole domain Ω or an appropriately selected sub-domain of Ω? Targeting these problems, the equivalent loading scheme (ELS) and equivalent matrix scheme (EMS) are proposed. It is theoretically analyzed that both ELS and EMS can be used to precisely simulating the effective properties and local fields of matrix-inclusion composities, and both ELS and EMS are self-approved. As an application, ELS combined with a so-called pseudo-dislocations method is used to evaluate the effective properties and local fields of two-dimensional two-phase composites with close-packed circular inclusions, or randomly distributed circular inclusions, or randomly distributed microcracks. The results show that substituting the remore traction σ^∞ with the effective stress field σ^ɛ suggested by IDD scheme is a simple and effective method, and the estimation of the effective properties and local fields is very close to the accurate solution. The present work is supported by the National Natural Science Foundation of China (No. 19525207).     

Some dynamic problems for elastic materials with functional inhomogeneities: anti-plane deformations

The paper considers two dynamical problems for an isotropic elastic media with spatially varying functional inhomogeneity, the propagation of surface anti-plane shear SH waves, and the stress deformation state of an anti-plane vibrating medium with a semi-infinite crack. These problems are considered for five different types of inhomogeneity. It is shown that the propagation of surface anti-plane shear waves is possible in all these cases. The existence conditions and the speed of propagation of surface waves have been found. In the section devoted to the investigation of the stress deformation state of a vibrating medium with a semi-infinite crack, Fourier transforms along with the Wiener Hopf technique are employed to solve the equations of motion. The asymptotic expression for the stress near the crack tip is analyzed, which leads to a closed form solution of the dynamic stress intensity factor (DSIF). Here also the problem is considered for five different functional inhomogeneities. From the formulae for DSIF thus obtained one can see that the inhomogeneity can have both a quantitative and qualitative impact on the character of the stress distribution near the crack.Received: 25 July 2002, Accepted: 3 April 2003, Published online: 27 June 2003PACS: 83.20.Lr, 83.50.Tq, 83.50.Vr, 46.30.Nz