ANÁLISE DINÂMICA DE PLACAS CONSIDERANDO O EFEITO DE MEMBRANA SUBMETIDAS A CARREGAMENTOS EXPLOSIVOS

Resumo

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 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.