Abstract

This year Nauti-Craft will be launching the world’s first recreational production vessel incorporating its patented whole of vessel suspension. This whole of vessel suspension system will be incorporated as a standalone “chassis” structure which will be integrated into the designs of its upcoming NS7 and NR7 vessels. This paper examines a portion of the design process, and the means by which such a unique system can be comprehensively engineered via simulation and analysis. Boat / ship design in general, has been part of our history for thousands of years. However, the push for innovation and innovative design tools is a more recent activity. The team at Nauti-Craft is now partnering with MSC Software (part of Hexagon) to introduce the innovative Frequency Domain fatigue analysis approach into their design process. The potential performance advantages of working in the frequency domain are: • The frequency domain approach requires one frequency response function (FRF) per structural configuration, compared with one for each event in a time domain modal transient analysis. Hence, the solver analysis is decoupled from the fatigue analysis allowing for multiple fatigue evaluations without rerunning the solver analysis. A significant time saver. • With careful planning, very large models can be easily handled in the frequency domain. • The approach can be easily used to generate diagnostic information such as damage per event, frequency at the peak response, contribution diagnostics of the loading channels, etc. • Response statistics like displacement and acceleration can be obtained and used for correlation purposes and as laboratory test data or used in the evaluation of relative response between parts to check on component gap development or part collisions under loading. • Analysis times are extremely fast which provides for design optimisation, even for larger models. This paper will show the required workflow for this innovative approach which includes, (i) gathering the response time histories from an MSC Adams analysis, (ii) converting the time histories to Power Spectral Density (PSD) matrix files and (iii) running a full random response and fatigue analysis as demonstrated on part of the NS7 design. The advantages of the Frequency Domain approach for creating useful diagnostic data will also be discussed.