Structural damage identification based on pattern matching using the flexibility change rate

Abstract In this paper, a rapid identification method for postearthquake structural damage is proposed based on pattern matching using the flexibility change rate. In the first stage, a small number of dynamic signals are collected for extracting the modal information, which is used as a reference for model updating. Using the updated finite element model of the structure to be monitored, the characteristic vector of the flexibility change rate is calculated by modal analysis from the first two orders of modal information of various damage scenarios to establish a pattern database. For the real structure, the measured responses are used to identify the modal parameters to calculate the flexibility change rate characteristic vector, which is treated as the observed pattern. Then, the similarity between the observed pattern and the pattern in the pattern database is calculated using the Euclidean distance (ED). The damage location and severity of the measured structure are treated to be the same as the pattern corresponding to the minimum value of ED, so that the damage is identified. Numerical simulations and experiments of two types of concentrated mass structures, four floors, and six floors confirm that the proposed method can identify the damage well. In addition, the matching results based on different sensor combinations demonstrate that the method can quickly identify the damage location and severity of a structure even using a limited number of sensors. The proposed method can provide support for the government in rapid postearthquake emergency decision‐making.