Research on damage identification of jacket structure under wind and wave loads based on variational mode decomposition and chirplet transform

To conduct damage localization and damage quantification of jacket structure, a new damage identification approach based on variational mode decomposition (VMD) and chirplet transform (CT) is firstly introduced. Three kinds of environmental loads, namely, regular wave load, irregular wave load, and wind load, are set on the jacket structure to simulate the real environment of the jacket as much as possible. The acceleration response signals of each node of the damaged bar are extracted and analyzed by VMD and CT. The proposed method is used to analyze the time-frequency energy changes before and after damage for damage localization. Then, the time-frequency entropy of the damage location is further calculated for damage quantification. The feasibility of the introduced method is verified by setting different operating conditions, and the results show that the proposed method can locate and quantify the damage of the jacket under different environmental loads.