Evaluation of the Limits of the Stability of Elements of Offshore Hydraulic Structures Taking into Account Accumulated Damages

Abstract

Offshore hydraulic structures are actively used for oil, gas and other resources in offshore fields. For example, in the Gulf of Mexico alone, approximately 4500 such structures are used. In connection with the operation in the world of a large number of marine hydraulic structures built more than 20 years ago, the task arises of assessing the residual life of these structures taking into account accumulated damage. It is obvious that the residual life of these structures will differ from those just put into operation. During the operation of these hydraulic structures in their elements, the accumulation of fatigue damage occurs as a result of which the strength and fatigue properties of the material of these elements change. The article investigates the problem of determining the endurance limits of elements of marine hydraulic structures taking into account accumulated fatigue damage. Based on the analysis of existing models for assessing the resource with accumulated damage, the author calculated the values of the shift of endurance limits relative to the initial fatigue diagram. As a result of studies, it was found that the endurance limit value on the fatigue diagram shifted down and to the right, which indicates an accelerated exhaustion of the resource of platform elements with accumulated damage.