Study On Dead Load Forming Of Hull Steel Plates

It is well known that the hull plates forming process by line heating is a highly complicated technique for the shipbuilding. Because of the huge geometric size of the ship hull plates, there is a relatively large column deflection caused by dead load, therefore some forming process of the hull plate maybe complete by the dead loading. The applications of this study result in a desirable future in that it may reduce the cost of shipbuilding and increase the production efficiency.In the paper, the following subjects were studied through theoretic study, numerical analysis and experimental means:1. The deflections of flat plate and column Shell caused by dead load are calculated based on elastic theory and finite element method, and the results are compared. It is shown that the results of ANSYS are accurate.2. The relatively large deflections of sheet are described and the models of finite element method are built and checked up by experimental measure of dead load forming. The database of the calculations for dead load forming of hull steel plates is established.3. Data of effective parameters are measured, and the effect principles of the primary parameters such as length, width, thickness, and radius are qualitatively analyzed. With curve estimate and multi-variable stepwise regression analysis methods, mathematical models for the dead load forming of hull steel plates based on the primary parameters such as length, width, thickness are presented. On the other hand, according to beam theory formula, other mathematical models are constructed with multi-variable stepwise regression analysis method. These two kinds of models are both accurate.4. Based on above algorithm, and combined with shipyard production condition, a forecasting system is developed for the dead load forming of hull saddle shaped steel plates. Factual plate tests in shipyard production show a forming precision of this system.5. On the basis of summarizing the previous results, it is indicated that the research works of boundary conditions and load in dead load forming should be carried on in the future.