Numerical Investigation of SAVER-BOX for Container Loss Mitigation Under Parametric Rolling on Ultra-Large Container Vessels

Abstract

This study examined the failure behaviour of container securing systems on ULCVs under parametric rolling. Although considerable efforts have been made to mitigate parametric rolling through improved ship design, operational guidance, and classification rules such as Roll Design Assessment, the complete elimination of extreme roll motions cannot always be guaranteed. Complementary structural mitigation strategies are therefore still needed to reduce container loss during such extreme events. An explicit FE model was used to simulate the sequential failure of twistlocks, lashing rods, sockets, and corner castings under a severe roll condition. A mechanical device, the SAVER-Box, was introduced to redistribute inertial loads and delay progressive structural collapse. Container loss was reduced from 93% to 20% when the device was applied. Stress and strain results indicated ductile performance within the assumed rupture limit. A new metric, PCL, was proposed, showing that isolated reinforcement shifted failure locations whereas system-level design improved overall resilience.