Experimental and numerical analysis of container multiple stacks dynamics using a scaled model

Abstract

This research aim to understand the mechanical behavior of container stacks under predefined driving excitation emulating real maritime conditions. The objects of study are scaled models (Froude scaling) of a 20 ft ISO freight container and its linking connectors, i.e., twist locks arranged in three adjacent seven-tier stacks. In the first stage of the study: a series of experiments were performed, using a shaking table, to build a database to calibrate a numerical model. The second stage of the study used a numerical model (F.E.A.) to understand the effect of structural changes and basic vibrational variables on the structural response of the stacks. The numerical analysis incorporates contact using the Kelvin–Voigt model. From the results it is possible to identify how each variable affects the structural response. Additionally, it is possible to calculate explicitly the loads on critical points of the structure. The evidence from this study suggests that the use of discrete damping elements, decreasing gap size and joining stacks, may help to minimize the structural response of the container stacks. The modeling of such a problem may provoke profound modifications on the current methods used to calculate loads on the stacks and securing (lashing) systems.