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.     

实验应力分析的光电-计算机自动数据处理(PCP)程序研究

本文提出的光弹性数据自动分析处理PCP程序,使输入计算机的数据数量达到最小限度.文中采用陈至达[1](1962年)的光测应力分析基本方程,并导出适合于光弹性数据处理的三次样条函数.初步实践证明PCP程序较目前其他研究者提出的自动应力分析方法更为准确和节省计算时间.     

有限变形非对称弹性理论变分原理

应用有限变形S-R分解定理,将体力矩重新定义为内外两种体力矩之和,给出了相应的变形能增率表达式及其物理意义,并进一步补充和完善了有体力矩作用下的有限变形力学的功率变分原理和余功率变分原理。     

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。     

非线性尺规近似法在圆杆颈缩局部有限变形分析中的应用

形变局部化和不稳定的研究是当前力学问题的一个热点,其中最典型的问题是圆杆拉伸颈缩和滑移带的塑性分析。传统的微小变形弹塑性力学不能彻底解决此问题。本文采用以S(应变)-R(转动)分解定理为基础的非线性尺规数值计算法,并应用计算机模拟优化技术求出圆杆拉伸轴对称塑性有限变形的局部应变分布与发展形态。     

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…     

On the representation of finite rotation in nonlinear field theory of continuum mechanics

One of the important basic theoretical problems in the development of continuum mechanics is the separation of finite strain and finite rotation at a point in the displacement field. Now it is certain that S-R decomposition theorem provides a rational theoretical solution for this problem. The purpose of this paper is to clarify some misleading basic concepts of finite rotation of deformed body in current literature, and to promote further progress.The detailed abstract of this paper was published in 1985 Shanghai International Conference of Nonlinear Mechanics. In the present paper some new results are included.     

EDITORIAL COMMITTEE OF "APPLIED MATHEMATICS AND MECHANICS

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ON UNILATERAL CONTACT LARGE DEFORMATION PROBLEM WITH FRICTION(Ⅱ)—NONLINEAR FINITE ELEMENT TECHNIQUE AND ITS APPLICATION

Based on the variational equation derived in ref.[1]a nonlinear incremental F.E.equation is formulated for unilateral contact elastic and plastie large deformationproblems.A new technique-co-moving coordinate finite element method is introduced,and a practical mathematical model for large deformation contact problem is described.To show the effectiveness of the method,problems of contact large deformation ofcantilever beam.cireular plate,as well as metal ring are computed.Compared withexperiments.the results show good agreements.