Feasibility Study For Health Diagnosis Of Jacket Structure Based On The Vibration Response Signal

Nowadays, the main types of offshore platform in China are jacket platform,which is mainly distributed in the depth of about30m in the Gulf of Bohai Sea. Afterdecades of development, the technology of jacket platform has been extremely maturein China, such as building, installation, production and maintenance. With theplatform into service later, many platforms are needed to do regular maintenancework, including the study of damage identification of jacket platform. At present, thedamage identification of the jacket platform is still in the experimental stage.Therefore, the damage identification of the jacket platform plays an important role inthe platform operation work and is also a hot and a focus view at home and abroad.This paper aims at this actual situation, combined with previous studies, research onthe feasibility study for health diagnosis of Jacket structure based on the vibrationresponse signal.Firstly, use finite element software ANSYS to establish finite element modalorient1-1jacket structure, determined environment loads by P-M spectrum, usingtransient dynamic analysis method to get the vibration response of the key point of thejacket platform. Then, introduces the method of modal parameter identification infrequency domain and time domain and reduce decrement. With this method, we canget the free vibration response signal of the structural by using the random decrement.Finally, using numerical analysis software MATLAB, Fourier Transform, ITD methodand complex exponential, get the modal parameters of the structure, so as todetermine whether the structure is damaged.The research of this paper provide a theoretical basis for the identification ofserving jacket platform structure damage diagnosis, it has a significant meaning on thesecurity service of the platform.