Structural health monitoring for layered structure using a force identification approach

Abstract

In this study, we proposed a structural health monitoring and diagnostic method for layered structures using the force identification of approach. This method belongs to the primary diagnosis one, and its purpose is to identify the location of abnormality quickly after abnormality detection. A feature of this method is that the displacement change caused by an abnormality in the structure is considered by applying additional force to the normal structure. In the early stage of abnormality, the stiffness of a certain layer will change, so the local additional force is identified, and the accuracy of the reconstructed displacement change is estimated. In the diagnosis of an actual structure, the actual vibration characteristics may differ from those obtained by the mathematical model. We also proposed a method for predicting the frequency response function in the abnormal state based on the difference between the actual measurement and the mathematical model in the normal state. First, we considered a five-layered structure as a numerical example and validated the proposed method. When we applied the method to three types of abnormal conditions, we found that the abnormality could be diagnosed correctly. Next, we constructed an experimental model of a five-layered structure and verified the applicability of the proposed method. We created a type of abnormal condition and showed that the abnormality could be diagnosed correctly. As described above, the validity and applicability of the proposed method were clarified.

Keywords

• structural health monitoring
• fault diagnosis
• inverse problem
• force identification approach
• layered structure
• normal state
• abnormal state