Development of a stepwise primary diagnosis method of a beam using a force identification and optimization approach

In this study, a stepwise diagnosis method is proposed. In this method, the location of abnormality is first estimated using the force identification approach. The point of the proposed method is that the abnormality is considered as an additional local force in the early stage of abnormality. After that, the cause of abnormality is identified. That is, the response of the structure with certain abnormality at the estimated location is calculated, the residual between the actual and calculated response is checked, and the correct cause of abnormality is identified. As a numerical example, a uniform beam supported by two springs is considered. Four types of abnormality are assumed to occur and the validity and applicability of the proposed method is checked. As a result, using the data without measurement error, the location and cause of abnormality can be exactly identified. On the other hand, using the data with measurement error, the location of abnormality can be estimated in the case of accurate measurement, and the cause of abnormality can be identified with sufficient accuracy. Therefore, the diagnosis method proposed in this paper is considered to be useful for the primary diagnosis.