Strain Softening Modeling of Concrete in the Post-Fracture Range

本项目拟研究混凝土材料断裂后变形破坏行为模型中应变软化塑性的理论基础；在理论研究的基础上，建立了包括断裂后软化行为在内的广泛应力条件下混凝土的全面三维应力-应变关系；将模型实现为三维非线性有限元分析程序，并通过求解一些具有实际意义的边值问题对程序进行验证。在本研究中，将在基于Ilyushin假设和断裂理论的塑性应变空间公式的总体框架下，重点研究混凝土材料在断裂后范围内的应变软化建模。一个更一般的应变空间公式，既考虑塑性和断裂的混凝土，将发展。

In this project, it is intended to study the theoretical basis of strain-softening plasticity in modeling deformational and failure behaviors of concrete materials in the post-fracture range; to develop a comprehensive three-dimensional stress-strain relation for concrete based on the theoretical studies covering a wide range of stress conditions including the post-fracture softening behavior; to implement the model into a three-dimensional nonlinear finite element analysis program, and to verify the program by solving some boundary value problems of practical significance. In this study, special emphasis will be placed on strain-softening modeling of concrete material in the post-fracture range, within the general framework of strain-space formulation of plasticity based on Ilyushin's postulate and the fracture theory. A more general strain-space formulation, which accounts for both plastic and fracturing of concrete, will be developed.