Structural Health Monitoring of High-Speed Crafts: Phase1 Development of Solution via Digital Twinning

Abstract High speed crafts demand lighter structural weight to enhance transportation efficiency, which, in turn, increases the risk of premature structural failure. As such the use of aluminium structures requires closer attention to fatigue cracks. There is a clear technological trend towards equipping high-speed vessels with Structural Health Monitoring (SHM) systems that provide structural diagnosis and prognosis capabilities to support operation and maintenance decisions. The intelligent data processing capabilities of a digital twin make it an ideal platform for achieving real-time structural health awareness of the entire hull, even with a limited number of sensors. Unfortunately, current digital twin applications for ship structures are primarily implemented on large displacement cargo vessels or offshore structures and are not readily applicable to high-speed crafts due to the unique challenges associated with predicting their responses: (1) lack of information of the highly non-linear slamming load experienced at high-speed; (2) the absence of efficient models to predict non-linear hydrodynamic responses under dynamic operating conditions, including planning effects, porpoising, and wave-induced motions. To address these challenges, a customized SHM solution via digital twinning has been developed for an ultra-high speed patrol craft (Froude number Fn>2.0). This paper presents the research work conducted in Phase 1. The Dynamic Loading Approach (DLA) and Spectral-Based Fatigue Analysis (SFA) are utilized for structural evaluation when the craft navigates at loitering speeds (Fn<0.4), Whereas a coupled Computational Fluid Dynamics (CFD)+Finite Element (FE) analysis framework is developed to address the slamming load effects on global and local structure responses in semi-planning or planning state (Fn≥0.4). The insights gained from these numerical analyses have been instrumental in designing the sensor placement plan and developing the architecture of the SHM solution, which serve as the foundation for SHM system development in Phase II. At last, a quantitative cost-benefit analysis has been conducted, highlighting the economic feasibility and added value of SHM implementation for highspeed crafts.