混凝土结构损伤的分形特征实验分析

在物理模型试验中分析了混凝土结构损伤演化中的分形行为，揭示了混凝土结构的裂缝生长及表面裂缝分布具有分形特性，表明分形维可以定量描述表面裂缝分布。利用分形几何学研究混凝土结构的损伤演化过程，证明了结构表面裂缝分布分形维与结构力学性能之间存在良好线性相关性，认为表面裂缝分形维可作为度量混凝土损伤程度的损伤特征因子。与基于振动理论的损伤特征因子相比，这一新特征因子具有自己的一些特色和优势，为创建新的混凝土结构健康诊断和安全性评价方法体系提供了一条新途径。

Experimental study on fractal characterization in damages of concrete structures

The fractal characterization in the evolving damages of concrete structures is studied based on physical model experiments. It is revealed that the surface-crack distribution of the damaged concrete structures takes on fractal behavior. This shows that fractal dimension is able to characterize the surface-crack distribution quantitatively. Then fractal geometry is employed to investigate the crack evolving process of concrete structures; and the relationships between the fractal dimension of surface-crack distribution and the mechanical properties of the damaged structures are discussed in detail. It is found that there exists a good linear correlation between the fractal dimension and the natural frequency, which shows that the fractal dimension of surface-crack distribution is able to act as a damage feature index to reflect the damage degree of concrete structures effectively. Compared with the conventional damage feature indices generated from vibration testing; this novel damage feature index is of some advantages and distinguishing features. It provides a promising approach to develop new technologies for structural health monitoring and safety evaluation.