جستجوی مقالات مرتبط با کلیدواژه « انفجار در آب » در نشریات گروه « پدافند غیرعامل »

An accurate and safer analysis for structure is possible if we can identify factors in the analysis more accurately. One of the important factors in the analysis is the identification the kind and intensity of structural loading. Among the types of loading, especially dynamic loads and impact loads resulting from the explosion, is far more complicated and difficult to determine. According to lab explosion modeling problems, using numerical modeling to analyze these phenomena can be reasonable. Uses grid methods like Finite element method caused a numerical error due to intense deformation and high velocity of blast. In this paper, underwater explosion was modeled and programmed with numerical mesh-less method, Smooth Particle Hydrodynamics (SPH), using Fortran programming language and explosion pressure and water level changes in the blast were studied. Finally the solving problem is compared with empirical relation. The results of this model are very similar to empirical relationship. This program can be used for underwater explosions modeling and the results can be used to determine pressures and impacts on marine structures.

In this paper، prediction of maximum response of a structure subjected to the impulsive loads، using of simple analytic relations developed for linear SDOF systems is presented. Duration of underwater explosion pulse in comparison with the natural period of studied structure in this paper is enough short to consider it as an impulsive load and hence، maximum response of the structure can be estimated without dynamic analysis. After modeling of concrete wall of cylindrical water tank used as an ''explosion test chamber'' in SAP2000 and explosion loading and analyzing of it in both static and dynamic methods، Results obtained from both SDOF and MDOF methods compared with each other and hence، the accuracy of the analytical relations based on the SDOF method in the estimation of maximum dynamic response of the structure was investigated. Considering that the response of the structure is mainly function of the impulse of the explosion in the structural and loading conditions studied in this paper، using an explosion loading function evaluating the impulse more precisely such as linear triangular pulse extracted from the field tests data results in more accurate response of a structure.

Analysis of compressive loading effect resulting from underwater explosion on steel structures in the diverse range of problems from the explosive forming of plates to study of explosion effect on ships body, submarines and marine structures have been applied and studied. In this paper with aim of design and construction of underwater explosion test chamber in a practical project, the effect of charge weight on plate deformation and weight effect and charge distance on fluid maximum pressure have been studied by using ABAQUS / Explicit software and the results have been compared with available experimental results and relationships and have been accurately confirmed. By verification of conducted simulation, the initial design of cylindrical test chamber in two states without stiffener and with stiffener under the effect of underwater explosion load has been assessed. In design of chamber by using stiffener the weight of chamber is reduced that has been effective in cost reduction.