混凝土剪切断裂能与分形维数关系的研究

A Study on the Relationship between Shear Fracture Energy of Concrete and Fractal Dimension

混凝土断裂试件断口蕴涵着丰富的力学信息,而传统的欧几里得几何难以对复杂的断口形貌进行描述.本文引入分形几何理论对断口形貌进行研究,结合宏观的断裂参量进行数值分析,从而找到了混凝土断裂微观现象与宏观力学量联系的桥梁.本文分析了混凝土四点剪切加载试件的断裂性能,计算了断裂韧度、断裂能等相关参数,并通过扫描电子显微镜对断口形貌观测,运用分形理论计算了此类断口的分形维数,分析了 型断裂断裂能和分形维数之间的关系.

The broken surface of concrete fracture specimen comprises plenty of mechanic information that is worthy of being studied carefully. However, traditional Euclid geometry cannot describe the complicated image of the surface of fracture. This paper introduces fractal geometry to resolve the problem, and bridges the gap between micro-image of fracture surface and macro-mechanics.The experimental results of four-point shear tests on concrete specimens are presented where the broken surface of concrete specimens is examined by scanning electron microscopy, and its fractal dimension is calculated with fractal theory. It is shown that a relationship does exist between the fractal dimension and type Ⅱ fracture energy of concrete.