Second-order effect of an elastic circular shaft during torsion

In this paper we deal with the second-order effect of an elastic circular shaft duringtorsion.The analysis is based on the method of co-moving coordinates and the strain-rotation decomposition theorem in continuum mechanics.By using asymptotic expansionmethods,we comfirm that the effect of axial elongation and distortion of plane cross-section exists in an elastic circular shaft during large torsion and give the expressions ofthe axial force and the torque.     

光弹性条纹自动检测分析系统

本文提出的光弹性自动检测分析系统,是通过光电扫描和微型计算机自动条集和处理光弹性条纹信息,能实时,准确、迅速地检测条纹密度变化很大的受力模型,仅在十几分钟内就可输出(显示和打印)全场应力光图条纹中心线及其坐标,而且结构简单,造价低(仅为其他类型的自动光弹性系统的十分之一到二十分之一).     

连续介质有限变形力学几何场论

连续介质力学有限变形非线性场论是近代力学重点问题之一.本文不同于Truesdell与Noll的极化分解定理,采用Helmholtz-Weyl的原则将连续介质空间运动的微分线性变换分解为正交与对称子变换之和.结果证明,正交变换对应于用Euler参数表示的有限转动;而对称变换对应于Cauchy应变张量定义在拖带系(co-moving system)内有限变形的自然推广.理论的一阶近似是古典的微小变形理论,二阶近似与Blot的结果等价.新结果改进了Truesdell与Noll理论所存在的缺点,提高了实用价值.作为应用举例,文中最后求出粘弹性液体Weissenberg效应爬升曲线的第一次近似解.     

ON THE REPRESENTATION OF FINITE ROTATION IN NONLINEAR FIELD THEORY OF CONTINUUM MECHANICS

One of the important basic theoretical problems in the development of continuummechanics is the separation of finite strain and finite rotation at a point in the displacementfield.Now it is certain that S-R decomposition theorem provides a rational theoreticalsolution for this problem.The purpose of this paper is to clarify some misleading basicconcepts of finite rotation of deformed body in current literature,and to promote furtherprogress.     

The application of nonlinear gauge mathod to the analysis of local finite deformation in the necking of cylindrical bar

IntroductionNeckingandshearbandaretypicalfailureformationofplasticinstabilityofductilemetals,thephenomenaoflocalizeddeformationthatoftenaPPearinexperiments.W.JohnsonpointedoutthattheinvestigationoflocalizeddeformationcouldbetracedbacktoTresca'sexperimentalsummaryin1878.Fromtheseventies,manyresearcherswerefurthermoreconcernedaboutthisstUdyinthefieldofmaterial,mechanicsandengineering.Localdeformationexistsnotonlyintheprocessofmetalbutalsoingeotechnicssuchastheslideplaneinslopestability.Locali…     

对“根据应力光图直接解答弹性力学平面问题的方法”一文的补充

自从作者在力学学报五卷三期上发表了“根据应力光图直接解答弹性力学平面问题的方法”一文以后,傅新民、杨槐堂、张永福等同志陆续对本文提出了一些宝贵意见,作者向他们表示感谢,并作以下两点补充说明。 1.原文中曾讨论平面体边界附近主应力方向的变动规律,其中的方程(15)     

带有摩擦的单边接触大变形问题的研究：（Ⅱ）非线性有限元解及应用

在文[1]所建立的增量变分力程的基础上,本文建立了单边接触弹塑性大变形问题的非线性有限元增量方程;进一步阐述了基于拖带坐标系的大变形有限元方法的特点,建立了实用的大变形接触模型.作为应用实例,计算了悬臂梁、厚圆板的弹性接触大变形和金属圆环弹塑性接触大变形问题,得到了令人满意的计算结果.     

Energy principle of large deformation for living systems

Living system is a non-equilibrium open system having the function of self-organizationand self-control.The study of energy principle of living system involves two principal parts:mechanics and thermodynamics.The classical infinitesimal deformation theory andthermodynamics of equilibrium state are not sufficient to explain the complex motion ofliving system.We aim in this paper to describe the mechanical energy principle ofmacroscopic motion of living body based on large deformation non-symmetry stress fieldtheory.The principle of irreversible thermodynamics applied to living system will be left inanother paper.     

钱氏定理在有限变形极矩弹性力学广义变分原理的应用

应用Lagrange乘子法和钱伟长证明的两类广义变分原理的等价定理,在本文中导出有限变形极矩弹性力学的广义变分原理.文中采用了在拖带坐标系描述法建立的有限变形应变张量(称为Biot有限变形应变定义的准确形式)和应变速率定义与拖带系应力张量构成完整的数学描述.     

多重孔隙介质的有效应力定律

通过对双重孔隙介质有效应力的研究,建立了多重孔隙介质条件下的有效应力定律,发现了有效应力定律的唯一性依赖于孔隙介质本构关系的假设,提出了多重孔隙介质有效应力定律的所有可能形式。