STRUCTURAL DESIGN OF HIGH SPEED VESSELS

摘要

I. Scope Following the report on Structural Design of High Speed Vessels presented at ISSC 2000, this report aims: 1. to give a brief but rather comprehensive view of major research results achieved during the last three years; 2. to focus on the new HSC Code, issued in 2000, and on its impacts on structural design and classification rules; 3. to provide an exhaustive review of the structural application of advanced composite materials, as explicitly required by the mandate. Even though the HSC Code is referred to civilian craft, some military vessels, having HSC characteristics, such as fast patrol and attack craft, have been taken into account. II. Development trends in recent years The increase in craft size has led to a more extensive use of "first principle design" approaches. The HSC Code and the classification rules allow novel design solutions to be accepted, provided they can be suitably supported and demonstrated by such approaches. New rational ways of predicting motions, loads and structural responses have been developed and included both in the rules and in computational methods, taking into account vessel operational restrictions. The need to ensure high performances, in terms of both speed and payload, has driven designers to the definition of lightweight solutions and the use of lightweight and stronger materials, even though higher design stress levels have led to a need for improved fatigue assessment of such structures, which are often subjected to a large number of cycles (even exceeding 10~7 to 10~8) in a rather short period. With regard to civilian vessels, the market has largely stagnated: apart from possible developments in terms of cargo craft, the main progress can be expected in the naval field, where high speed low and medium size vessels are designed and built for fast attack and coast patrolling purposes. This trend is confirmed also by some naval regulations, which make explicit reference to HSC rules, like for instance DNV Rules for Classification of High Speed, Light Craft and Naval Surface Craft and RINA Rules for the construction and maintenance of the quality standard of Italian Coast Guard Vessels.