Structural Damage Identification Based On Cloud Model

Damage identification of structure is an important research direction in the field of civil engineering, related to people's lives, property safety and social impact. Developing accurate and efficient structural damage identification methods has very important theoretical and practical value. This paper reviewed the research of structural damage identification, and described the status of research on cloud model. Then, damage identification theory related to modal strain energy and finite element method for dynamic analysis of structures were elaborated in detail. Strain energy dissipation ratio index method proposed by Liu Hui et al and strain energy equivalence index method proposed by Guo Huiyong et al were referred to. The effect of the two methods were analyzed and compared at last.Secondly, the basic theory of cloud model is introduced, including the digital characteristics of the cloud as well as the basic nature of the cloud. All of these reflect the relationship between fuzziness and randomness, laying a foundation for the application of cloud model in the uncertainty reasoning of structural damage identification.Then, primary application based on cloud model based on normal cloud model and expectation-entropy curves was presented. Its progressive in quantitative aspects was demonstrated by numerical simulation, and its performance under different noise levels and variable degrees of damage was discussed.Finally, in order to deepen the cloud model application in structural damage identification, a one-rule-based cloud generator was constructed with a one-dimension antecedent generator and a one-dimension consequent generator, used to carry out uncertainty reasoning. The antecedent generator was constructed by modal stain energy of each damaged unit, and the consequent generator was constructed by the degrees of cell damage. The rule base of qualitative reasoning system was deduced by entropyweight method and gray cloud model. The concrete calculation steps of cloud reasoning were given in this paper. The effectiveness of this method in structural damage identification was demonstrated by two-dimensional truss structure and threedimensional truss structure, and its performance under different noise levels and variable degrees of damage was discussed.