The Calculation, Analysis And Research On The Structure Problem Of The Barge In The Transportation Of Heavy Cargos

The structure strength of a ship is one of much attention-getting and the most important question in the stage of research, design, construction and operation of the ship. It is different from the traditional transportation of goods in that the deck barge to transport the heavy cargos is a special ship varying from the common ship. In the transportation of the heavy cargo, the problem of structure strength of the barge is especially standing out.It is a precondition for the contract signing between the owner and shipper that the structure can load the heavy goods and operate safely. So, there is a very important realism meaning for the dissertation to research the structure strengths of the barge.According to the practicable experiences, it is very easy to satisfy the general longitudinal strength of a barge for properly loading and ballasting. In a general way, the local strength of the barge structure is confirmable and anxious. It is a importance problem and must be solved.Firstly, the general longitudinal strength is calculated with the "hull girder" theory of a large semi-submergible deck barge (Zhongren 1602) whose carrying capacity is 15000 tons with one super large caisson(l 1351.53 tons) loading on it. With the help of the international widely-used software ANSYS, the thesis adopts the Direct Strength Method(DSM) to calculate the local structure strength. Under the defined loading, it makes up a three dimensional model to calculate the local strength of the barge, and makes up a two-dimensional models to calculate the strength of the local structres such as the side shell and transverse bulkhead and the main deck. And the buckling strength is also calculated and checked. After analyzing and evaluating the results, several suggestions about operation and structure reinforcement to meet the need of project are offered.Specially, the structure stability of the main deck is studied. After summarizing the results of former researchers, some analyses are separately performed for all kinds of buckling modes of the grillage structure. In the analysis of the elastic local buckling strength of the plates in stiffened plates, an analytical expression is derived for calculating the local strength of a stiffened plate subjected to biaxial thrust considering plate/stiffener interaction. In the analysis of the elastic local buckling strength of the stiffener's web, the elastic critical stress is analytically derived by solving the eigen value problem involving the governing differential equation under the corresponding loading and boundary conditions. In the analysis of the elastic tripping of the stiffener, the critical stress under this mode of failure is derived by using the energy method and the principle of least potential energy .Finally, the load support capability of the main deck is calculated. Then, the work designer and operator can know accurately of the capability of the barge deck .The calculation mode and the research are not only for the barge "Zhongren 1602" but also for the other barge and relative project.