Abstract 

A primary limiting component for a ship’s service life is the hull structure.  In particular, a ship’s fatigue life remains one of the major design issues naval architects are faced with in terms of how a design is initially assessed during early stage design, and what mitigating steps can be taken to control fatigue damage throughout the structural system’s service life.  To address this very complicated subject, industry has implemented and exercised various long-standing approaches; however, many of these approaches are exercised during later stages in the design process, or after construction or even while a vessel is in service.  Remediation of any issues that are found can be very problematic and costly.  Further these established approaches typically do not directly function within a larger life-cycle framework system as such systems still remain to a large extent only with the research and development community.  Therefore, establishing an efficient and robust process that allows the naval architect to perform global fatigue screening of acceptable details in the primary hull structure early in the design process and throughout the service life is invaluable.  This process and all of the necessary underpinnings are now found within the software suite MAESTRO. 

The paper first aims to present the methodologies, procedures, and results from conducting an analysis using a simplified fatigue assessment rooted in beam theory, and contrast that with a more extensive approach using a spectral-based fatigue analysis procedure implemented in MAESTRO.  Second, the paper will present more generally how the MAESTRO software open framework and the MAESTRO Spectral Fatigue Analysis implementation serve as key ingredients to the vision of implementing a fully functional life-cycle framework for maintenance, monitoring, and reliability of ship structures.  It will be discussed how a completely implemented and functional life-cycle framework can mitigate, among other things, extensive fatigue damage in the hull girder.