A Computational Method For Slamming Loads Of Ship

Exact computation of slamming pressure is complex and important. This paper mainly focuses on the practical direct prediction of bottom slamming pressure and flaring slamming pressure acting on the ship.Firstly an introduction of prediction technique is made, where their advantages and disadvantages are discussed.The fully nonlinear free surface boundary condition is adopted and the similarity solution on the symmetrical wedge oblique water entry problem is given. The problem of this similarity flow is solved by a boundary element method together with an analytical solution for the jet based on the shallow water approximation. Results are provided for the pressure distribution at different deadrise angles and at different oblique entry speed. The effects of horizontal speed on these results are investigated.The water entry problems of two-dimensional ship section are simulated by the MSC.Dytran finite element analysis software. Some studies on the key techniques of simulation such as non-reflection boundary condition and fluid initial condition at simulation are carried out and programmed.The practical prediction method of slamming pressure is brought forward. The slamming pressure and pressure distribution along the three-dimensional ship body are calculated in time domain by combining the three-dimensional motion theory with the empirical formula or numerical simulation technique. There will be too much work to do if numerical simulation is applied to estimate the slamming pressure. So, some programme is developed to build the finite element mode and write the input files of MSC.Dytran. Batch program is also used to help the analyzer to manage the input files and the result reports.