Análise dinâmica de placas considerando efeito de membrana submetidas a carregamentos explosivos

Abstract

The behavior of civil engineering structures under blast loads has been studied quite frequently in the last years and much effort has been made to create idealized blast wave curves and predict the corresponding response of structural and protective elements. The blast phenomenon results in an abrupt overpressure wave followed by an underpressure wave, the last being usually disregarded in most structural analyses. However, recent studies show that this suction phase is of paramount importance since it may lead to substantially higher displacements and stresses. In the case of high-intensity pressure waves, structural elements may experience large displacements, thus requiring second-order effects to be included in the analysis. This work investigates the nonlinear dynamic behavior of thin rectangular plates subjected to explosive charges. The problem was modeled as a nonlinear single degree of freedom system by applying von Karman’s theory for large deflections to simply supported and clamped plate configurations. A uniform pressure load simulates the overpressure and underpressure waves by employing the Friedlander equation and a cubic approximation, respectively. Runge-Kutta method was used to solve the equation of motion for displacement amplitude. Numerical solutions for displacements and stresses were derived for several plate geometry configurations and blast loads, making it possible to measure the influence of the suction pressure and the membrane effect on the plate response.