Study On Ice-induced Fatigue Characteristic Of Jacket Platform

Ice load is the most preponderant factor to the working offshore platform in ice region. Ice induced vibrations will result in structural damage to any extent. The higher level of maximum ice load will even completely push over the structure in a short time. Alternating stress produced by alternating dynamic ice force evidently results in the partial fatigue failure. Accordingly the ice-induced fatigue analysis is very important and significative for offshore platform.This paper is grounded on the project from Bohai Oilfield Services LTD in which the tubular joint's ice-induced fatigue strength of JZ20-2NW jacket platform is analyzed. Based on the characteristics of the structure and information received, the data needed for calculation and analysis method was decided; with the environment data and the basal data offered by contractor, the data are analyzed and the usefuls are selected; according to the serviceable data and the distribution of the ice data the structure's numerical model is formed and ice-structure interaction model is decided to get the stress response curve; with the stress response curve calculated out the structure's fatigue damage can be achieved.After the fatigue damage analyses of the platform have been done, the relation between ice force and the fatigue damage is discussed in this paper and an approach to reduce the calculating work has been found. Some useful conclusions drawn in this paper will give valuable technical support for future analysis of ice-induced structure fatigue strength.