Comparison Research on Modal Parameters Identification of Measured Vibration Response Signals of an Offshore Substation Platform

Abstract

Abstract It is difficult to simulate and forecast the operation and security of offshore substation platform in service through a numerical model. Based on the vibrational response signals measuring from offshore substation platform, one can monitor the real-time state of offshore substation platform after obtaining its modal parameters via automatic ERA and SSI modal identification methods. Considering the sophisticated composition of environmental loads, and vast quantities of data, it is hard to use the ERA and SSI method to procure the modal parameters of substation platforms directly. Therefore, the automatic modal parameter identification method, which can cope with these severe conditions at sea, is introduced for the sake of obtaining the frequency and damping of offshore substation platform. The results indicate that: by making a comparison between the modal parameters in the design stage and those in operational states, the method proposed in this paper can identify the frequency and damping of the offshore substation platform accurately. Consequently, it comes the conclusion that the security of the offshore substation platform is still safe. Anyway, the method proposed in this paper furnish designers with a new way to forecast the states of structures and improve their designs.