Damage detection for shear structure based on substructure approach and dynamic photogrammetry

In this paper, a new damage detection method for shear structure based on substructure method and dynamic photogrammetry is proposed. The presented substructure method can identify the damage in shear structure using the absolute acceleration responses of structure measured by acceleration sensors. However, because of the iterative measurement of each substructure, a considerable amount of sensor installation and cabling work are still needed to be done and it would be difficulty or dangerous to install sensors and wiring on some parts of structure. Fortunately, as a non-contact measurement method, the dynamic photogrammetry can provide displacement response of measurement points conveniently and quickly. In order to reduce the impact of camera movement or the difficulty in selecting external reference points, the relative displacement responses are adopted in this paper. Therefore, the substructure algorithm and damage indices corresponding to relative displacement responses are need to be studied. In this paper, the adopted substructure algorithm and the relative displacement responses are introduced. And then, the ARMAX model (i.e., autoregressive moving average with extra input model) of each substructure is used to construct the damage indices using the relative displacements. The derivation of the relationship between the relative displacements of each substructure is also a novelty of this paper. Finally, the dynamic photogrammetry is introduced to obtain the relative displacement responses of each substructure. Based on the proposed damage indices and dynamic photogrammetry, the new damage detection method for shear structure is established. The proposed method is verified using a six-degree-of-freedom system and a laboratory plane frame. The results show that the proposed method can effectively identify the damage in shear structure.