APPLICATION OF 3-D NONLINEAR WAVE-LOAD AND STRUCTURAL-RESPONSE SIMULATIONS IN NAVAL SHIP DESIGN

Despite the limits inherent within linearized frequency-domain ship mo tion and wave load computer codes, strip theory has been found to prov ide the design community with a fairly robust, practical design tool w ith reasonable accuracy for most conventional displacement monohulls. However, the advent of new design concepts including multi-hulls and a pplication of new materials as well as the push to incorporate reliabi lity methods within surface ship structural design criteria has highli ghted the need for more rigorous methods of developing a lifetime load spectrum. In this paper, a multilevel computation system for predicti ng ship motions and wave loads, up through and including extreme sea c onditions, is presented. This system includes a traditional strip theo ry approach and newly developed linear and nonlinear three-dimensional time-domain methods. The new nonlinear methods are currently in the p rocess of being validated by the U.S. Navy. The status of the current development is presented. Sample numerical results from the new nonlin ear methods are compared with both linear frequency domain predictions and model tests.