Damage Detection Of Spatial Steel Structures And Noise Sensitivity Analysis

This paper reviews the significance,development and present situation of structural damage detection and health monitoring. Vibration-based global damage detection method is a hotspot of current research. This paper presents a comprehensive introduction to the various damage identification methods.The advantages and disadvantages of each method are outlined.As the experimental techniques of the structures are limited, the surrounding environment of large and complex civil engineering structures is complex, the uncertainty and the interference in the process of measurement and other factors, the measured data of civil structural response must be affected by noise. In view of this situation, considering the randomness of noise and damage stability characteristics, simply supported beam, three-dimensional frame, Benchmark framework model and offshore platform structure are analyzed to compare the ability to suppress noise interference among the flexibility difference curvature method, modal strain energy method, modified modal strain energy method and CMCM method by finite element numerical analogy. It is necessary to consider the recognition method noise immunity, but also need to consider the structure of its own characteristics. The results show that the modified modal strain energy method and CMCM method have good noise immunity for one-dimensional structure and frame structure. It provides screening, testing, comparison of methods for the implementation of engineering in the future.This paper systematically studies damage detection methods based on modal strain energy and summarizes the present situation of them in both home and abroad, axial modal strain energy ratio method is proposed on the basis of the existing methods. The major advantages associated with the new method are that it only makes use of pre- and post-damage modal natural shapes that are available for only the first and second-order modes. Additionally, the new method does not require the testing information of rotational degree of freedoms. First, numerical study of jacket offshore platform based on modal parameters generated from finite element models is carried out. Next, the new method is tested with the noise resistance. Finally, the new method is testified again with the physical model of offshore platform.According to the results, the new method is shown to be effective for the complex structural damage detection and has a good noise resistance. There is hope to apply it to practical application.