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基于梯度塑性本构理论的岩样侧向变形分析(II): 尺寸效应及弹性回跳
引用本文:王学滨,刘杰,王雷,潘一山.基于梯度塑性本构理论的岩样侧向变形分析(II): 尺寸效应及弹性回跳[J].岩土力学,2004,25(7):1127-1130.
作者姓名:王学滨  刘杰  王雷  潘一山
作者单位:辽宁工程技术大学 力学与工程科学系, 辽宁 阜新123000
基金项目:国家自然科学青年基金项目(编号:50309904)
摘    要:提出了利用不同尺寸试件的轴向应力-应变曲线得到轴向应力-侧向应变曲线的一种方法,并研究了结构尺寸对轴向应力-侧向应变曲线的影响。根据尺寸不同试件的轴向应力-轴向应变曲线的实验结果,并基于梯度塑性理论的解析解,在应变软化阶段,确定出了各种试件的剪切带条数。由此求出了不同宽度试样的轴向应力-侧向应变曲线。剪切带条数与试件宽度之比是决定轴向应力-侧向应变曲线特征的关键指标。若该比率为常量,则上述曲线不具有尺寸效应。当宽试件及窄试件在局部化启动后,在试件内部都出现一条剪切带时,随着试件宽度的增加,该曲线越陡,甚至出现回跳。上述方法也可用于分析轴向应力-环向应变曲线的尺寸效应问题。尺寸效应的原因是局部化,但局部化并非总引起尺寸效应。

关 键 词:梯度塑性理论  尺寸效应  局部化  侧向变形  回跳  剪切带条数  试件宽度
文章编号:1000-7598-(2004)07-1127-04
收稿时间:2003-04-13
修稿时间:2003年4月13日

Analysis of lateral deformation of rock specimen based on gradient-dependent plasticity (II):size effect and snap-back
WANG Xue-bin,LIU Jie,WANG Lei,PAN Yi-shan.Analysis of lateral deformation of rock specimen based on gradient-dependent plasticity (II):size effect and snap-back[J].Rock and Soil Mechanics,2004,25(7):1127-1130.
Authors:WANG Xue-bin  LIU Jie  WANG Lei  PAN Yi-shan
Institution:Department of Mechanics and Engineering Sciences, Liaoning Technical University, Fuxin 123000, China
Abstract:Influence of structural size on axial stress-lateral strain curves due to shear localization is investigated and a new method for determining the axial stress-lateral strain curves is proposed according to the axial stress-strain curves obtained by tests for different sizes. Using the analytical solution of the axial stress-axial strain curve based on gradient-dependent plasticity, linear regressions on the experimental axial stress-axial strain curves in strain-softening regime are carried out to calculate the number of shear band for different widths. After the number is determined, the axial stress-lateral strain curves for different sizes can be obtained according to the analytical solution of axial stress-lateral strain curve depending on the number of shear band and width of specimen. It is found that the ratio of the number of shear band to the width of specimen is a key parameter for describing the axial stress-lateral strain curves. If the ratio remains a constant, then the curves are size-independent. Otherwise, the post-peak curves are dependent on the width of specimen. For a single shear band appears in specimens with different widths, specimen with larger width leads to steeper curves and even exhibits snap-back behavior. The method proposed can also be used to analyze the problem of size effect of axial stress-circumferential strain curves. The reason for the size effect is shear localization, but the case that localization can not cause the size effect is not also impossible.
Keywords:gradient-dependent plasticity  size effect  localization  lateral deformation  snap-back  number of shear band  width of  specimen
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