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991.
992.
The cavitated bifurcation problem in a solid sphere composed of two compressible hyper-elastic materials is examined. The
bifurcation solution for the composed sphere under a uniform radial tensile boundary dead-load is obtained. The bifurcation
curves and the stress contributions subsequent to the cavitation are given. The right and left bifurcation as well as the
catastrophe and concentration of stresses are analyzed. The stability of solutions is discussed through an energy comparison.
Project supported by the National Natural Science Foundation of China (No. 19802012). 相似文献
993.
R.C. Picu 《Journal of the mechanics and physics of solids》2002,50(9):1923-1939
The functional form of non-local elasticity kernels is studied within the context of the integral formalism. The study is limited to linear isotropic elasticity. The kernels are derived analytically based on the discrete structure of the material at the atomic scale. Atomistic simulations are used to validate the results. Materials in which the interatomic interactions are represented by pair, as well as embedded atom-type potentials are considered. The derived kernels have a range which extends up to the cut-off radius of the interatomic potential, are positive at the origin, and become negative approximately one atomic distance away, thus departing from the commonly assumed Gaussian functional form. The functional form of the potential and the radial distribution function of interacting neighbors about a representative atom fully define their shape. This new continuum model involves two material length scales that are both derived from atomistics for a Morse solid and for Al. Two applications are considered in closure. It is shown that in strained superlattices, the non-local model predicts maximum stresses that are much larger than those obtained within the local theory. This observation has implications for defect nucleation in these structures. Furthermore, the new non-local model improves upon the Gaussian one by predicting a more realistic wave dispersion relationship, with essentially zero group velocity at the boundary of the Brillouin zone. 相似文献
994.
微重时卧圆柱内静液面方程与数值计算 总被引:2,自引:0,他引:2
由力学平衡方程导出了微重时卧圆柱内静液面方程,推出了边界接触角条件,使用Runge Kuta法在计算机上得出了数值结果,绘出了静液面形状,并对结果进行了分析. 相似文献
995.
力学可以为农业现代化作贡献 总被引:10,自引:0,他引:10
农业现代化提出了许多与力学各个分支都有密切关系的问题.从农田耕作、农业物料性质、农产品烘干、水果和蔬菜生产、农业生物环境、节水灌溉、农业水土资源合理利用和作物生长等方面,介绍了有关的力学问题和目前的研究进展. 相似文献
996.
光滑拉伸试件中不同初始形状孔洞长大的有限元模拟 总被引:2,自引:0,他引:2
本文对具有不同硬化指数(n=0.05,n=0.1,n=0.2)的幂硬化材料的光滑拉伸试样的拉伸变形过程进行了有限元模拟,通过有限元计算和经Bridgman修正分别得到了试样变形过程中心部应力三维度随应变的变化情况;在此基础上运用控制体胞宏观应力三维度的方法,对含不同初始形状孔洞的体胞模型进行了有限元分析,计算结果表明:(1)孔洞初始形状和材料硬化特性对试样的拉伸破坏过程有重要影响;(2)Bridg 相似文献
997.
不同材料交界面上接触应力的有限元分析 总被引:9,自引:1,他引:9
工程中有许多不同材料组成的结构。对这类复合结构,正确计算材料交界面上的接触应力是非常重要的。通常的位移有限元法得到的应力是不连续且欠准确的。本文提出了一种新的用于不同材料交界面处的接触单元。应用虚位移原理和结合考虑材料交界面上的约束条件,文章建立了接触单元的刚度矩阵和等效荷载向量。该单元具有算法简单,程序容易实现的优点。计算实例证实了该单元的实用性和可靠性。 相似文献
998.
Vagn Askegaard 《Experimental Mechanics》1995,35(4):315-321
A normal stress cell and a shear stress cell have been designed and tested under very varied conditions including permanent
strain. Results pooled from nine different tests with the cells embedded in cohesionless materials (sand and wheat) showed
that the coefficient of variation of the normal stress-cell sensitivity was 0.04, while it was 0.10 for the shear cell. The
agreement between predicted and measured sensitivity was considered to be good for the normal stress cell and reasonably good
for the shear stress cell.
The shear cell showed a systematic dependence, within acceptable limits, of the total stress state in the surrounding material.
A qualitative explanation of this phenomenon is given.
Paper was presented at the SEM VI International Congress on Experimental Mechanics held in Portland, OR in June 6–10, 1988. 相似文献
999.
An extension of the Elastica theory is developed to study the large deflection of an elastic-perfectly plastic horizontal
cantilever beam subjected to a vertical concentrated force at its tip. The entire process is divided into four stages: I.elastic
in the whole cantilever; II.loading and developing of the plastic region; III.unloading in the plastic region; and IV.reverse
loading. Solutions for stages I and II are presented in a closed form. A combination of closed-form solution and numerical
integration is presented for stage III. Finally, stage IV is qualitatively studied. Computed results are given and compared
with those from small-deflection theory and from the Elastica theory. 相似文献
1000.
FengWenjie WangLiqun JiangZhiqing ZhaoYongmao 《Acta Mechanica Solida Sinica》2004,17(3):258-269
I. INTRODUCTION Owing to the intrinsic coupling characteristics between electric and elastic behaviors, piezoelectricmaterials have been used widely in technology such as transducers, actuators, sensors, etc. Studieson electroelastic problems of a piezo… 相似文献