A Study on the Improvement of Prediction Accuracy of Hull Fatigue Life using a Fatigue Damage Sensor

摘要

A pro-active safety management system for ship structures thatrnquantifies the aging effect such as fatigue and corrosion on shiprnstructural integrity is proposed as a new approach to the ship'srnstructural surveys that have conventionally been done according to arnmore passive management system.rnIn a proposed fatigue management system called the 'Hull FatiguernManagement System' (HFMS) using Fatigue Damage Sensors (FDSs),rnit is an important problem to improve the prediction accuracy of hullrnfatigue life using the FDSs.rnThe characteristics of the FDSs that are in use for fatigue life evaluationrnby monitoring structural members in ship structures are discussed inrnorder to improve the prediction accuracy of fatigue life exposed tornrandom wave loads such as storms under various loading conditionsrnpeculiar to ship structures.rnFactors affected by random loading against constant-amplitude loadingrnand mean stress levels are introduced for the evaluation procedurernusing FDSs and confirmed by a series of fatigue testing and numericalrnsimulations.rnThis newly proposed fatigue life evaluation procedure using obtainedrnfactors is checked by comparison results of fatigue tests for a largernstructural model on which FDSs and strain gauges are providedrnsimultaneously and to which random loads by assumption of stormrnpatterns are applied under various mean stress levels.rnPractical application results of the FDS for an LNG Carrier for 5-yearrnoperation are discussed.