A Comparison of Linear SDOF and MDOF Methods for Analysis of Thick Concrete Structures Subjected to Underwater Explosion

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Abstract

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.

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