用三维离散元实现混凝土Ⅰ型断裂模拟

MODEⅠ-FRACTURE SIMULATION OF CONCRETE BASED ON 3D DISTINCT ELEMENT METHOD

为了进行从连续介质到非连续介质转化的数值模拟,实现结构破坏全过程的仿真分析,本文基于三维变形体离散元法,分别采用弥散的旋转裂缝模型和分离裂缝模型分析了混凝土、岩石等准脆性材料的受拉开裂行为。通过单轴拉伸算例和对比三点弯梁试验的数值计算与试验结果,说明在确定的断裂能情况下,两种断裂模型均能够合理预测结构的荷载位移响应;并且基于离散单元法的分离裂缝模型不仅可以获得裂缝开裂过程荷载位移全曲线,而且可以实现系统部分或完全失效溃决过程的仿真分析。

For the purpose of numerical simulation of transition process from continua to discontinua and even to structural collapse, the fracture of quasi-brittle materials such as concrete and rock under tensile state is analyzed by rotating smeared-crack model and discrete crack model based on the deformable distinct element method （DEM）. The models are then applied to analyze the problems of uniaxial tension and three-point bending beam test. The comparison between experimental and numerical results shows that the models are able to appropriately predict the load-displacement response of the beam under uniform fracture energy. The discrete crack model is not only capable of obtaining the load-displacement curve of the entire fracture process but also of simulating the collapse behavior when the system partially or completely reaches failure.