Influence of clapboard and protective layer on domino effect risk caused by fragments from spherical vessel explosion

The fragment flight and damage to the target were investigated in consideration of the clapboard and protective layer based on the plasticity concepts, and the movement equations of fragment in three-dimensional system after its complete penetration to the clapboard were developed. A spherical vessel with fragment projection was taken as an example to explore the influence of the clapboard and protective layer on the domino effect risk by Monte-Carlo simulations. The results show that the clapboard only prevents the projectiles in the range of its size and reduces the impact probability to some extent, but the protective layer occupies the larger probability of rupture and cuts down the failure possibility of target significantly. The relative deviations demonstrate that the protective layer performs more than 90% reduction in the domino effect risk, accounting for 2 to 3 times of that produced by the clapboard. The risk of domino effect occurrence decreases exponentially according to the thickness of the protective layer, and the research can provide theoretical basis for the design of the protective measures of spherical tank. The interaction between the tank and the fragment should be tried to avoid in order to stop the domino effect.