Research On Damage Characteristics And Damage Identification Method Of Jacket Platform

Over the past few decades,researchers have made extensive research on the damage identification of offshore platforms,and proposed many damage identification methods.However,previous studies have focused on the damage of cracks,while other types of damage to offshore platforms such as corrosion,scour,sedimentation and sag are not well studied.It is necessary to establish other types of damage identification methods and to consider different types of mutual interference in damage identification.In this paper,the status of research on structural damage identification and the progress of research on damage identification of offshore platform are introduced.Damage identification theory based on dynamic characteristics and neural network algorithm and genetic algorithm applied to damage identification are introduced.For crack damage,based on the natural frequency and modal confidence,the influence of crack damage degree and damage position on the dynamic characteristics of the structure is systematically analyzed.With corrosion and scour regarded as influence factors,the effects of corrosion and scour on dynamic characteristics and on damage identification of the structure are analyzed.The neural network-based Crack damage identification method is improved,which can better reduce the erosion and erosion impact on the damage identification.The cross-modal strain energy theory considering the mass change is proposed.The quantitative identification ability of traditional cross-modal strain energy and the effect of mass change on the quantitative identification of erosion and erosion damage are analyzed.The corrosion thickness identification method and the scouring depth identification method based on the genetic algorithm are proposed,which has good recognition effect on both single damage and multiple damage conditions.The stress response of both undamaged and damage platform structure under wave and current loads are analyzed,and a damage monitoring method based on stress variation is proposed to identify the fracture of bars.Under the circumstance that damage identification methods based on dynamic characteristics are not yet mature,the proposed method has a greater engineering application value.