Distinguishing between Sensor Deterioration and Structural Damage

Current detection methods for structural damage only consider environmental or operational effects on damage detection, but neglect the problem that sensor performance degradation can be caused by environmental changes, and thus seriously affects the damage detection accuracy. In this paper, a method for distinguishing between sensor performance degradation and structural damage is proposed, which is based on the fact that the sensor performance degradation is local, while structural damage is global. In this method, the minimum mean square error and the generalized likelihood ratio test (GLRT) are used to detect and locate the abnormal response in a structural system. Besides, the modes of the control index fluctuation out of the limit of the statistical quality control chart are used to judge the source of abnormal responses. A numerical study is performed to validate the proposed method via a simple-supported beam. The results show that the GLRT can effectively detect the abnormal responses, and the statistical quality control chart is capable of distinguishing between the degradation sensor and damage accurately. If the control index fluctuation out of the limit of the statistic control chart shows a stable mode, the abnormal response comes from structural damage; otherwise, it comes from sensor performance degradation.