Direct Calculation Of Structural Strength And Optimization Design Based On Engineering Ship

With the continuous development of shipping, ports functions of the growing, Floating crane become one focus of China shipbuilding, especially the demand for medium and large tonnage floating crane. Markets driven by the needs and interests have leaded the way to a new trend, the use of the old ship conversions.As floating cranes are intended for special operations, its hull structure, due to specific loads, are more complicated. For such a complex structure and load distributions, traditional structural strength calculation method has given the way to a new once. With the development of computer hardware and software technology, it's now possible to make a model of whole ship and apply the finite element analysis on such model. Strength analyses of the hull structure have a revolutionary breakthrough. Classification societies around the world are constantly looking for a more scientific and reliable method of design. The direct calculating method of ship structural strength becomes necessary in today's shipbuilding industry. Entire hull finite element model rests on the FEM software. In order to express their real components of the inter-force conditions, respectively, bar, plate, beam, shell, and other units to simulate the different components of the state by force. And calculate through finite element analysis software, among all components of the actual results of the stress deformation.In this examination, advantage of finite element software MSC.Patran and MSC.Nastran has been taken on the study, and optimization for conversion program of a 500t floating crane barge. The crane hoists have independent models, computer support anti-Block Office, and then use Multi-Point Constraint to load the deck corresponding to the location of the hull. Outboard water pressure equivalent to the concept design waves in the sag and hog conditions. Adjust the average draft of the hull to balance of the hull. The use of "Inertia Relief feature, the structure of the hull can be in a "completely free" status.On the study of the hull structure security, buckling strength analysis of deck and floor are essential and necessary. In accordance with the FEM model, analyze the buckling intensity of the floating crane's deck and floor and strengthen the weak parts. In the frame of the hull plating buckling strength aspects of verification, CCS (China Classification Society) developed the grid plate buckling strength calculation plug-in based on Patran. In this examination, we use this plug-in for partial plates buckling strength checking of the hull and verification of the two different calculation results were analyzed.As the ship conversion programs have a direct impact on the entire project cost and construction program, the structural optimization of the hull is very necessary. Based on the inconvertibility of the original parts of the hull, added component thickness have been optimized. It makes the whole design more economic and feasible.