Probability Prediction On Bottom Slamming Loads For Box Barges

With the world's shipbuilding industry development, new types of ships and marine structures are emerging, and are more and more evolved in the role of fluid-solid coupling, in which ship slamming is one of these complex and practical problems. Slamming load is one kind of non-linear wave loads, classification societies and research departments attach great importance to them. Therefore, a reasonable determination of slamming loads and the analysis of various factors on the impact of slamming pressure is of great significance to guarantee the safety of the ship and the design of a reasonable structure.This paper studies the bottom slamming load characteristic of the box-shaped barge, include the following:1. For 5 different scale box barges, three-dimensional hydrodynamic models were created to calculate the weight distribution parameters of the hulls in the typical conditions. By using DNV Software WADAM/SESAM, the ship's motion response amplitude in regular waves was calculated. By using POSTRESP/SESAM, the short-term prediction of relative motion and velocity between the hull and the wave under environmental conditions was made.2. Ochi's ship slamming probability theory and Chuang's three-dimensional ship slamming forecasting method was analysized. The bow slamming loads predictive points were selected reasonably and the slamming loads coefficients was established. By using the theory, the probability of bow slamming occurrence, the number of occurrence per unit time and the slamming pressure extremum of the 5 box barges in different drafts, towing speeds and floating conditions was predicted. The relation curves among the probability of bow slamming occurrence, the slamming pressure extremum and the towing speed and there distribution curves.3. Based on the above calculations, the general rule of the probability of bow slamming occurrence and the slamming pressure extremum of the box barges is studied. Aiming at the effects of draft, towing speed and floating condition on the slamming characters of box barge, a detail analysis was made. After analysis the thesis holds that, towing speed between 10 to 12 Kns is the inflexion of the increase amplitude, could be regarded as the critical speed whether to strengthen due to slamming. Floating condition affects the slamming characters significantly, and must be taken account for slamming strength requirement.