Structural damage detection of a cantilever beam under varying temperature using a collection of time series

Abstract Condition monitoring of structures in service assesses the risk of damage development. Its essential constituent is the damage detection methodology. In the context of condition monitoring of in service structures a damage detection methodology analyses data obtained from the structure while it is in operation. Usually, this means that the data could be affected by operational and environmental conditions in a way that could mask the effects of damage on the data. This, depending on the damage detection methodology, could lead to either false alarms or failure to detect existing damages. In this article a damage detection methodology that is based on the Spatio-Temporal Continuous Wavelet Transform (SPT-CWT) analysis of a sequence of experimental time responses of a cantilever beam is proposed. The cantilever is subjected to pink noise and it is manually heated by a heat gun in order to impart varying temperature conditions. The response of the cantilever beam is measured by a high speed camera. Edges are extracted from the series of images of the beam response captured by the camera. Subsequent processing of the edges gives a series of time responses on 439 points on the beam. This sequence is then analyzed using the SPT-CWT to identify damage.