Effect of interfacial friction and fold penetration on the progressive collapse of foam-filled frustum using kinematically admissible model

Abstract

In this article, we extend our earlier analytical efforts of the progressive collapse of foam-filled conical frustum with the aid of a kinematically admissible folding mechanism. The instantaneous crushing force as well as the mean crushing force were derived from the principle of energy conservation accounting for the typically overlooked term of foam/shell interaction. Specifically, in this study, we accounted for the effect of two critical parameters upon the accuracy of our upper bound solution. The first is concerned with interfacial shell-foam friction. The second is with a more realistic proportion of the fold involved in the foam/shell interaction. The results of the analytical model are compared with nonlinear elastoplastic finite element collapse predictions as well as validation with our crush test results. The results reveal the effects of the interfacial friction and the modified fold proportion upon the accuracy of the analytical model and its ability in predicting the crushing force curve and the fold length.