Relay Replacement

Risk-based methods for inspection and maintenance can significantly reduce lifecycle cost by basing inspection and repair intervals on the risk of incurring damage rather than on arbitrary periods. Not only can the methods reduce inspection cost anddowntime, they can actually increase ship reliability and safety by defining explicit failure probabilities for all important components and functions. SoHaR and its subcontractor, EQE/ABS (a part of the American Bureau of Shipping), propose to develop aRisk Based Maintenance Strategy Tool (RBMST) to support a risk-based maintenance approach for the LPD 17. The innovations of our approach include the use of a probabilistic fracture mechanics model as opposed to the traditional SN curves. The benefit ofa probabilistic model is that it yields a failure probability rather than an expected life. The RBMST will also integrate corrosion and fracture fatigue mechanisms in a single model, account for previous repair history, and incorporate cost and safety.The model uses a conditional probability approach to account for past maintenance and repair actions. A prototype tool using the Matlab program will be delivered at the end of Phase I. The prototype will include sophisticated modeling capabilities,results plotting, and a graphical user interface. The team members combine a unique combination of expertise in probabilistic methods and domain expertise in marine and ship structures that will ensure project success.Risk based maintenance is becomingincreasingly important in all aspects of the marine and offshore technology industries. The benefits relative to fixed periodic maintenance programs are lower downtime and decreased inspection costs. The probabilistic fracture mechanics approach that isbeing used in the RBMST provides a significant advantage over the traditional engineering