Numerical Forecast And Research Of Trimaran’s Wave Loads And Seakeeping

Along with the human deeper exploration of the ocean,the traditional conventional vessels could not meet the challenge,therefore a variety of high-performance ships emerged. Among them, the trimaran with its stealth performance, small sailing resistance, wide deck, survival ability, improved seaworthiness, low construction costs, large room for modification and decent navigation performance has attracted increasing attention and rapid development. Compared with the monohull, trimaran has wave hydrodynamic characteristics with complex features, but relatively little research on wave hydrodynamic performance of the trimaran ship has been achieved. Secondly, accurate prediction of ship motions in waves is a prerequisite for reasonable design of ship structure, for determining the motion of a ship in waves, and for accurate calculation of the necessary parameters for all sections of the ship wave load. Therefore, the research in this area becomes more significant.Before writing this article, what needs to do first is depth study theoretical knowledge of trimaran seakeeping, wave loads, including a two-dimensional panel method, two-semi-dimensional theory and three-dimensional linear theory methods; grasp the methods of trimaran seakeeping, wave loads forecasts, comprising short-term forecast, long-term forecast; it is also required to study in-depth relevant ship professional softwares, such as finite element analysis software Patran, and hydrodynamic calculation software Hydrostar.In this paper, a 120 metre long trimaran passenger ship is used as an example. With the help of the line drawings, the three-dimensional finite element model was achieved using finite element analysis software Patran, as well as the grid unit, and by the use of the ship hydrodynamic calculation software Hydrostar, the seakeeping and wave load transfer function (RAO) was obtained, additionally the analysis about how the trimaran hydrodynamic performancethe was influenced by wave frequency, ship speed, wave direction angle of. Combined with the IACS recommendation No.34 wave data, with the probability level of 10-8, the swaying motions, the vertical motions and the wave loads of the trimatan were calculated, including the short-term prediction and the long-term prediction, using direct calculation method to calculate the motion amplitude and the wave force of the trimaran.