In this paper, the longitudinal ultimate strength of a high speed trimaran is studied by testing and numerical simulation. First of all, the longitudinal ultimate strength is examined by the model test, after that, the ultimate strength of the test model and the actual ship are calculated by the nonlinear finite element analysis (FEA) which considers the material nonlinearity, geometrical nonlinearity and follower force, The longitudinal ultimate bending capacity of the actual high speed trimaran is predicted by the model testing result and the similarity relation of model and ship ultimate strength are studied.
A high speed trimaran is a kind of high-performance ship in terms of its perfect transverse stability, sea keeping capacity and quick accelerating performance. Therefore, it has very wide prospects of research ships, maritime shipping, maritime transport, exploration and rescue boats, etc. The quick accelerating performance of a trimaran is achieved by its finer main and side hulls than single hull vessels of the same displacement. However, it is necessary to examine the strength of its finer hulls, especially longitudinal ultimate strength. Now, there are some common methods used to study the ultimate strength of hull girder, such as direct calculation method, idealized structural unit method (ISUM), progressive collapse analysis based on Smith's method, nonlinear finite element method and collapsing tests of scaled models or full scale ship, etc. On the one hand, it is very difficult to completely predict the ultimate bending capacity by numerical simulation because the ultimate strength problem involves geometric and material nonlinearities. On the other hand, the feasibility of full scale test method is too inadequate because of the expensive cost and stringent condition. So it is necessary to adopt a feasible method to estimate the ultimate strength of ship hulls.
