A blast absorber test: measurement and model results

A blast absorber test was conducted at the Aberdeen Test Centre from 13 to 17 June 2005. The test was set up to determine the absorbing and shielding effect of a gravel pile, of 1.5 meters high and 15 by 15 meters wide, on blasts from large weapons: e.g. armor, artillery or demolition. The blast was simulated with single brick C-4 charges of 570 grams. Both short range and long range acoustic measurements were performed. A control site was used as a reference to determine the sound reduction effect. This joint project was performed by: a) the US Army Engineer Research and Development Centre (CERL, Champagne, IL and CRREL, Hanover, NH), b) The Netherlands Ministry of Defense (DRMV, the Hague), and c) TNO (Delft). Measurement results are shown for three source positions: above the gravel, behind the gravel at 3 meters height and behind the gravel at 1.0 meters height (thus using the gravel both as an absorber and screen). The results are compared to results from a non-linear model which propagates the highly non-linear blast wave over the gravel. Further, a hybrid model is presented which propagates the blast up to several kilometers from the source. The model can support the design of absorbing and shielding measures to reduce the noise of low frequency sounds such as army training artillery fire.