Progress in reconstructing blast fields from shoulder-fired weapons is reported. By quantifying full body blast exposure from weapon operation, better injury correlations can be constructed. Blast exposure data from training events along with scene descriptions were used to estimate full body blast exposure on subjects in the scene. These advances are based on combining event recordings from an individually worn sensor system called the Blast Gauge and situational data to reconstruct the 3D blast exposure on the subject (warfighter) with three dimensional (3D) fluid dynamic simulations. Reconstruction of the full body blast loading enables a more accurate assessment of injury due to air blast even for subjects not wearing Blast Gauges themselves. The Blast Gauges are typically used in sets of 3 with 1 each on the head, shoulder, and chest to provide pressure exposure and acceleration at each location. By accurately understanding the blast exposure and its variations across an individual, more meaningful correlations with injuries including brain injury and eardrum rupture can be established.

A high fidelity three dimensional fluid dynamics tool called SHAMRC (Second-order Hydrodynamic Automatic Mesh Refinement Code) was used for the analysis. CAD (computer aided design) models for subjects in the scene accurately represent body positions and locations of subjects in the blast field, including the gunner, assistant gunner, and range safety officers (RSO). Reconstructions were performed on data from a wide range of weapon types, including the Carl Gustav, AT4, SMAW, and LAW. A propellant burn model was created for each weapon to capture blast effects. The analysis takes in point data (from Blast Gauges) and the output is a total blast load distribution (overpressure) for all personnel involved. Experimental validation has been performed on the simulated weapon back blast. As blast injury thresholds become better defined, the data from these reconstructions can provide important insights into approaches for reducing risk of injury to personnel operating shoulder-launched weapons.

Acknowledgments

This research was developed with funding from the Defense Advanced Research Projects Agency (DARPA)