ABSTRACT

Damage in concrete has been modelled using various approaches such as fracture mechanics, continuum damage mechanics and failure envelope theories. This study proposes a new approach to model the initiation of damage in concrete that addresses some limitations associated with the existing approaches. The proposed approach defines damage in terms of changes in the density of the material at the microscopic level, where such changes are induced by mechanical loading. The suggested approach is used to simulate the response of 2D concrete bodies to uni-axial tension and uni-axial compression. The simulation results indicate that the proposed model, by means of a single constitutive function, is able to correctly predict failure patterns and aptly capture the damage mechanisms under both uni-axial tension and uni-axial compression loadings using only the information related to the microstructure, the density field and the stiffness field. As a continuation, in Part II, the ability of the D3-M approach to model fully coupled chemo-mechanical damage in concrete using a single constitutive equation will be demonstrated.

摘要

混凝土中的损伤已经使用各种方法进行建模，例如断裂力学、连续损伤力学和失效包络理论。本研究提出了一种新方法来模拟混凝土中损坏的开始，解决与现有方法相关的一些限制。所提出的方法根据材料在微观水平上的密度变化来定义损伤，其中这种变化是由机械载荷引起的。建议的方法用于模拟二维混凝土体对单轴拉伸和单轴压缩的响应。仿真结果表明，所提出的模型，通过一个单一的本构函数，能够仅使用与微观结构、密度场和刚度场相关的信息，正确预测失效模式并恰当地捕捉单轴拉伸和单轴压缩载荷下的损伤机制。作为继续，在第二部分中，将展示 D3-M 方法使用单个本构方程模拟混凝土中完全耦合的化学机械损伤的能力。