The Application Of Rough Set Based On Information Entropy In Structure Damage Detection

The course in the use of structure, because of design, construction, use or environmental reasons, often happen the varying degrees damage, which affects the structure's force function. Once the structure damaged, will cause structural stiffness and natural frequency changes, which led to changes in structural dynamic response. To guarantee the safety of the structure, we need checking out the positions and dimensions of these damages in order to conduct a reasonable method of the reliability of structure operation. So the research on the damage detection in structure is paid more and more attention by researchers and becomes an important measure that ensures the structure to run well.Recently, many researchers have proposed some intelligent methods that apply to the damage detection in structure. These methods include fuzzy logic and ANN. They improve the running of the damage detection in structure system effectively. However, these detection methods are essentially based on pattern-recognition and pattern classification. When there are many patterns, there exit these problems, such as rules explode and the difficulty to do with incomplete and inconsistent information. Considering this, we introduce rough set theory.The main contribution of the dissertation can be summarized as follows: Firstly, in the course of applying rough set method, we discuss how to discretize the data. The general algorithm of attribute reduction and value reduction is presented, from which the attribute reduction algorithm based on information is proposed. Secondly, the conception, development and effect of entropy are expounded in detail. In the selection of character parameter of damage detection in structure, entropy is introduced for the first time. Thirdly, the application of discretizing data and reducing information table in rough set is studied, and the damage detection in structure of rough set theory based on information entropy is set up. Fourthly, a cantilever beam model is taken as the numerical analysis exemplification to demonstrate the effect of this method. Finally, some future research directions on the damage detection in structure based on rough set are highlighted.