Study On Hull Girder Strength Of Ship And Stress Analysis Of A Simply Supported Plate With A Cutout

During the process of the building and working of ship and offshore engineering, it is a key technology of assessing their structural strength. And the correct assessment is helpful to reduce the construction cost and increase the life and safety of the ship. Because the tonnage of ship is becoming huger and huger, it's a perfect and efficient method to calculate the structural strength using finite element method (FEM).Plates with different types of cutouts are common in many engineering applications. These cutouts which are located in the webs of double bottom are made to lighten the weight of the structure, to provide accessibility to other parts of the structure, and so on. Generally, the presence of such a large opening in the structure will obviously result in changes in stress distribution, besides a reduction of strength of the webs. According to the statistical reference, lots of damages in ship's structure are occurred the area around the opening, so it's important and necessary to study the effects of openings in the ship's members.This article includes two aspects as following: Part 1: Researching on the ship hull structure direct calculating method; Part 2: Studying the theory of elastic mechanics of plane. Part 3: Discussing the stress distribution of large-opening in the ship structure.Firstly, based on the content of JTP Rules written by International Association of Classification Society (IACS), the basic principle and content of direct calculation is presented, and then in accordance with the rules and guides in JTP, a three-cargo FEM model which is section of a 450,000 DWT is presented in the article.Secondly, theory of elastic mechanics of panel is learned and as well as the theoretical solution of stress distribution of opening plate.And finally, the concentration of stress in common opening plate is calculated using the ANSYS 8.0 software. According to the comparison of results of stress using different web sizes, the proper web size is chosen, and then two sets of models of round and round-rectangular openings are created.After this, the influence to structure strength in simple force and boundary is calculated in condition of variable shape and dimension of the opening. Based on the analyses of the results, the influence of strength of openings to thin plates is presented.