Nonlocal Damage Theory Based on Micromechanics of Crack Interactions
Nonlocal Damage Theory Based on Micromechanics of Crack Interactions
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DOI：
10.1061/(asce)0733-9399(1994)120:3(593
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发表时间：
1994-03
期刊：
影响因子：
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通讯作者：
Z. Bažant
中科院分区：
文献类型：
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作者：
Z. Bažant
利用Kachanov的简化叠加法，通过对宏观非均匀(非均匀)相互作用和扩展微裂纹系统的细观力学分析，导出了应变软化损伤的非局部连续介质模型。通过寻找一个可能的离散近似与控制相互作用的微裂纹系统的矩阵方程重合的连续统场方程，得到了均匀化。其结果是一个关于未知非局部非弹性应力增量的Fredholm型积分方程，它涉及两个空间积分。从裂纹相互作用由裂纹长度上的平均应力而不是裂纹中心应力决定这一事实得出的一个积分表示非弹性宏观应力的短期平均。第二积分的核是长程裂纹影响函数，它是一个二阶张量，随方向角变化(即各向异性)，表现出屏蔽和放大的扇形。为了L..。
A nonlocal continuum model for strain‐softening damage is derived by micromechanics analysis of a macroscopically nonhomogeneous (nonuniform) system of interacting and growing microcracks, using Kachanov's simplified version of the superposition method. The homogenization is obtained by seeking a continuum field equation whose possible discrete approximation coincides with the matrix equation governing a system of interacting microcracks. The result is a Fredholm integral equation for the unknown nonlocal inelastic stress increments, which involves two spatial integrals. One integral, which ensues from the fact that crack interactions are governed by the average stress over the crack length rather than the crack center stress, represents short‐range averaging of inelastic macro‐stresses. The kernel of the second integral is the long‐range crack influence function which is a second‐rank tensor and varies with directional angle (i.e., is anisotropic), exhibiting sectors of shielding and amplification. For l...