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考虑板厚效应或材料损伤的裂纹尖端场

作　者: 靳志和
导　师: 黄克智；余寿文
学　校: 清华大学
专　业: 固体力学
关键词: 清华大学博士学位论文裂纹尖端场损伤材料材料损伤弹塑性分析三维效应硬化材料渐近解局部解
分类号: O346.5
类　型: 博士论文
年　份: 1988年
下　载: 165次
引　用: 0次
阅　读: 论文下载

内容摘要

The three-dimensional effects near crack-tips and crack-tip fields of brittle damaged materials are investigated in this paper. The main results are as follows:1. An infinite plate containing a finite through crack under tensile loading is analyzed by using Fourier transform based on the Kane-Mindlin kinematic assumptions. The variation of SIF with plate thickness is obtained and the size of 3D deformation zone near the crack tip is evaluated as three-fourths of plate thickness.2. A new FEM formulation based on the K-M assumptions including transverse shear effects is first presented. The K-M assumptions are extended to elastic-plastic problems and the corresponding FEM formulation is established. The computational results show that the 3D deformation zone is confined within the extent of two of plate thickness near the crack tip when the ratio of plastic tangential modulus E_t to Young’s modulus E is greater than O.2.3. The asymptotic near-tip stress, strain and damage fields for a modeⅢcrack and a mode I crack in an incompressible medium are obtained according to the Mazars’s damage model for concrete. A simplified damage model for concrete is proposed and an exact solution for a modeⅢcrack is obtained based on the simplified model under the small scale damage conditions. Finally, the near-tip fields for a modeⅢcrack in a creeping damaging material is tentatively analyzed.

全文目录

Abstract  3-6
前言  6-11
第一章板厚对裂纹前缘弹性三维效应区的影响分析  11-38
  1 基本方程与边值问题  12-17
  2 问题的积分变换求解  17-23
  3 裂纹尖端附近的渐近解  23-25
  4 裂纹前缘的三维效应  25-35
  5 线性硬化材料的近似分析  35-38
第二章裂纹前缘三维效应区的有限元分析  38-59
  1 弹塑性本构关系  39-40
  2 考虑横向剪切变形平板的弹性有限元法  40-43
  3 考虑横向剪切变形平板的弹塑性有限元法  43-48
  4 计算结果——裂纹尖端附近的三维效应区  48-59
第三章脆性损伤材料中的裂纹尖端场  59-80
  1 弹性损伤材料(混凝土)裂纹尖端大损伤区中的应力应变场  60-64
  2 小范围损伤条件下弹性损伤材料Ⅲ型裂纹的全场解  64-73
  3 蠕变损伤材料中的Ⅲ型裂纹  73-80
结论  80-82
致谢  82-83
附录A 关于裂纹尖端应力强度因子  83-85
附录B 基于全量理论的弹塑性增量本构关系  85-87
附录C 双边裂纹拉伸试件弹塑性应变场的实验测量  87-91
附录D 关于几个简单蠕变损伤问题的全耦合解析解  91-100
参考文献  100-106

考虑板厚效应或材料损伤的裂纹尖端场

内容摘要

全文目录

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