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混凝土作为多相复合材料,其力学行为复杂多样,结构响应具有明显非线性,采用宏观本构模型精确描述存在较大难度。基于微观水平的混凝土本构模型——微平面模型M7,通过二次开发接口,将其嵌入具有较强非线性分析能力的通用有限元程序ABAQUS,对混凝土单轴压缩及拉伸、三轴压缩进行了模拟分析,通过与相关试验结果比较,验证了基于微平面模型子程序的有效性;为规避应变局部化引起的网格敏感性问题,将非局部理论引入微平面模型,研究了混凝土矩形面板与三点弯曲梁的应变软化问题。结果表明:微平面模型M7能够较好地模拟混凝土应力-应变全曲线过程,及多种应力状态下的力学行为;结合非局部理论的非局部微平面模型用于混凝土结构的有限元分析,不存在网格依赖性问题,能够给出合理的结构应变软化局部化响应,数值模拟结果合理可靠。
As a kind of multiphase composite material, the mechanical behavior of concrete is complex and diverse, and the structural response is obviously nonlinear. It is difficult to accurately describe the structure with macroscopic constitutive model. Based on the microscopic level concrete constitutive model-micro-plane model M7, through the secondary development interface, it embeds ABAQUS, a general finite element program with strong non-linear analysis ability to simulate the concrete uniaxial compression and tension, triaxial compression The simulation results are compared with those of the related experiments to verify the validity of the subroutine based on the micro-plane model. In order to avoid the grid sensitivity caused by strain localization, the nonlocal theory is introduced into the micro-plane model. The concrete rectangle Strain softening of panel and three-point bending beam. The results show that the micro-plane model M7 can simulate the whole process of stress-strain curve and the mechanical behavior under a variety of stress states. The nonlocal micro-plane model with non-local theory is applied to the finite element analysis of concrete structures. The existence of grid-dependent problems can give reasonable structural strain softening localization response, and the numerical simulation results are reasonable and reliable.