Direct damage index based on inverse finite element method for structural damage identification

Structural damage identification is the core problem of structural health monitoring (SHM). The traditional damage detection methods are restricted in the practical applications, due to factors including the complete measured data and modal information required before and after damaged states. Strain damage indexes have attracted wide attention due to their high sensitivity to local damage. This paper proposes a damage identification method based on the inverse finite element method (iFEM). Moreover, only by the limited strain sensor values, the strain field and the complete modal data are both obtained. It greatly improves the practicality of directly using the strain data for damage identification. The damage index is established only by the strain modal data after damage to localize damage. In order to further verify the effectiveness of the iFEM, the proposed method is numerically demonstrated by a cantilever plate subjected to single damage and multi-damage conditions. The results show that the iFEM can accurately reconstruct the deformation, and the direct damage index (strain mode difference) based on the iFEM can realize damage detection and provide a new research approach for SHM.