Experimental and numerical analysis of container stack dynamics using a scaled model test

This paper describes an approach to simulate a seven-tier stack consisting of scaled model of a 20 ft ISO freight container and its linking connectors, denominated twist locks, subjected to dynamical load induced by its base. The physical (dimensions, mass, and moments of inertia) and structural (longitudinal, transversal and torsional stiffness) characteristics of the scaled models were decided based on two dimensionless numbers: ratios between gravity force and inertia force, and elastic force divided by inertia force, through experimental and numerical analysis. A series of experiments with controlled parameters were performed using a shaking table test to understand the effects of each variable in the container stack dynamics and present enough data to validate the numerical model. The results of this study indicate that the numerical model built is a promising tool for further study. Moreover, the model is able to predict conditions close to real situations faced by container stacks while storage on a ship's deck.

► We study the structural response of a seven-tier container stack subjected to vertical excitation.
► The goal is to identify relevant factors behind container losses through numerical simulation.
► The model is a scaled version of a 20 ft container and its linking components, i.e., twist locks.
► We obtain correlation of dynamic properties depending on amplitude, frequency, gap size, etc.
► We suggest course of action to prevent container losses, e.g., to chance twist look geometry.