Extreme Motion Analysis and Simulation for Ship Design and Operations

Abstract

ABSTRACTNaval architects of the world use static approximations to allow for dynamic effects in the prediction of stability. With the advent of powerful computers, engineers can now model dynamic responses of ships within hours and operational staffs can have the benefit of these capabilities in a more real time setting.Six years ago a Cooperative Research Navies (CRNav) project was established to develop dynamic stability criteria and study the physics of extreme motion phenomena. The project is sponsored by a Dynamic Stability Working Group which includes members from the Australian, Canadian, Netherlands, United Kingdom, and United States Navies, and U.S. Coast Guard along with the Maritime Research Institute Netherlands (MARIN). As a result of the work done to date, a time domain motion analysis program has been developed. This program includes the capability to model a steered ship in extreme sea conditions and display animation to allow the user to visualize surfriding, broaching, capsizing and other extreme events. The use of this program and the criteria developed from the CRNav project will lead to significant improvement in the various nations' ship design and operational guidance capabilities. This paper outlines work done to date to develop a dynamic stability analysis system and includes a discussion of the Cooperative Research Navies project: explaining findings for capsizing physics and criteria; the time domain ship motion simulation program FREDYN, including its animation software and validation; proposals for extensions to damaged ship conditions, and the future of U.S. design and operational applications.