The effect of explosive charge backing in close-proximity air-blast loading

•Metal charge backing increases the impulse transfer to a structure•Transient and permanent midpoint deflections increase with charge backing•Magnitude of impulse increase is not the same as deflection with charge backing•Numerical simulations reveal the effects of recirculation on the clamp boundary This paper presents new insights into the influence of explosive charge backing on the impulse transfer and transient response characteristics of plates subjected to close-proximity air blast loading. The results of the combine experimental and computational studies show the critical influence of charge backing, which caused between a 3-5 times increase in the impulse transfer when the charge was metal-backed. The permanent deflections from the metal-backed detonations were larger than for air, but not to the same degree as the impulse increase. These findings demonstrate the important influence of charge backing, in close proximity detonations, which greatly exceeded anything previously measured. These valuable insights will assist blast protection engineers considering the effects of explosions in situations when the charge backing is something other than air, which is a frequent occurrence in explosion scenarios.