Simplified FEM Fatigue Analysis Method for Non-tubular Joint of Jacket Platform

Taking an in-service jacket platform as an example,this paper studies the simplified fatigue analysis method for the skirt pile sleeve(which is a complex non-tubular joint structure) of a jacket platform subjected to wave load.SACS software was used for global structural analysis for the jacket platform under multi-directional wave loads,the load case set and loads and boundary conditions needed in the simplified FEM fatigue analysis were chosen,then ALGOR software was used to build a finite element model and perform finite element analysis.After stress output post-processing,the fatigue analysis results were obtained.This simplified fatigue analysis method and its analytical results were recognized by DNV,that means the simplified fatigue analysis method is effective and can be used in fatigue design for the non-tubular joint structure of an offshore jacket.