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In this research behavior of bubble due to under water explosion and it’s effects on ship structure have been studied. For determination of these effects field equations must be derived and solved them by mathematical simulation. Mathematical model is com in follow, it show physical rules on impression of bubble oscillation on body ship. This model is solved by combination of Euler method, 5 step Adams-Beshforse method and 4 step Adams-Moltone method for explaining the response of ship structure due to oscillation bubble. In order to agreement of solution way, stress-strain curves that obtained in this paper, is compared with experimental results. Also this results compared with FEMA results. Ship structure is modeled in ANSYS software in free beam form with variable mass and stiffness elements. Internal ship’s equipments and buoyancy are modeled by local mass and spring. The effect of explosion depth and explosive mass on stress in ship structure is studied. These result show when explosion depth is increased, stress is decreased and when explosive mass is increased, stress is increased.

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One way to convey the occurrence of explosion under water and its effects on the structures is to use coning shock tube. By using a small explosive, this tube causes high pressure. In this essay, by suing LS-DYNA code, the explosion of a subsidiary amount of an explosive in the conning shock tube has been scrutinized. A numerical simulation has been done by using the MMALE (Multi Material Arbitrary Eulerain Lagrangian) solving method. To verify the validity of the selected method in software, first, the empirical tests performed by LeBlanc and Shukla is simulated. After assuring of the precision of the results, simulation of the desired problem is performed. In this research, first, the effect of the angel of the cone's head in the caused pressure inside the tube has been checked. Then, the operation of shock tubes with different lengths is checked. At the end, with the conversion of the weight of explosive, the study of the results and the reasons of the conversions in each parameter, a bond for the equivalent mass for all the shock tubes with different angels is represented and the bond for the present theory has been revised.

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Today, in order to reduce the cost and increase the safety, utilizing tests devices like conic shock tube has been popularized to investigate the explosion under-water phenomenon and its impact on constructions. A shock tube is designed, manufactured and utilized in the mechanic of explosion laboratory of mechanic faculty of K.N. Toosi University of Technology to study the effect of isotropic metal plates’ material in this research. The source which creates the shock in the utilized shock tube is the explosive material and the positive point is that in such a tube a high pressure can be produced with a tiny explosive charge. In order to investigate the effect of the material and the geometry of the utilized metal plate, three material is considered with two different thicknesses in the experimental tests. The behavior of the plate can be measured when the amount of the pressure produced by the explosive charge and the amount of plate’s transformation is specified. From the results of the experimental tests, in order to give a semi experimental relation, the behavior of the plate under the explosion load with the water interface is utilized. At the end, with the combination of experimental and theoretical results, the effect of material and thickness change are studied separately and with the increase in the weight parameter of the load, equations are given to predict the transformation of the metal plates.