Coupled multibody dynamics analysis of load redistribution in marine deck-cargo securing systems following local lashing rupture

Marine deck-cargo securing systems transfer loads through lashings and the cargo–deck interface, but local lashing rupture can disrupt this load-transfer system. A coupled multibody dynamics model is developed to resolve post-rupture response. The main novelty is the development of a coupled rupture-modelling framework that resolves post-rupture load redistribution in non-standard deck-cargo securing systems. Unlike conventional intact-state formulations and prescribed line-disconnection rupture scenarios, the framework simultaneously deactivates the failed lashing's axial capacity, tangent stiffness, and end-constraint reactions. The model is assessed against experimental lashing-tension measurements and an MSC.ADAMS benchmark. The peak lashing-tension error against the experiment is 1.11%, while signed peak differences relative to MSC.ADAMS range from −5.24% to 3.70% across force responses. The results show that released loads are redistributed through both the remaining lashings and the cargo–deck interface. The failed-lashing location governs the dominant load-takeover path, with the maximum remaining-lashing tension increment reaching 0.52 kN after L4 rupture. Among the deck-motion-component cases, coupled roll–pitch–heave excitation produces the largest remaining-lashing tension increment and activates both load-transfer routes, supporting the assessment of non-standard marine deck-cargo securing arrangements.