Dynamic response of polyurea coated thin steel storage tank to long duration blast loadings

Cylindrical steel storage tanks are often under the threat of long duration blast loadings induced by the explosion of flammable vapor clouds, and therefore the blast response and mitigation method of the tanks are of great importance to related industries. In the meantime, polyurea coating material, which has been proved to be effective in the blast mitigation of different structures, is employed in this study for the protection of steel storage tanks. Gas blast experiments, as well as numerical and theoretical models, are utilized to investigate the response and energy absorption mechanism of steel tanks and analyze the effect of polyurea coatings. The numerical results showed that the bending of the plastic hinge lines and the tension of the connect zone of the cylindrical shell are the main energy absorption ways of the tank. The modified beam-on-foundation model is then established and verified and the model indicates that the polyurea coatings mainly influence the displacements of the tanks by increasing the area density and bending moments of the tanks. Quantitative analysis on the effect of polyurea is conducted utilizing the response spectrum of the tank's equivalent system and the range of displacement reducing ratio caused by polyurea and the appropriate spraying strategy of polyurea are acquired accordingly. At last, further numerical simulations are performed and give results that validate the theoretical predictions.