This is very interesting. Though I'm somewhat puzzled at how the experiment was performed.
The article states that "
The researchers took turns placing different helmets on a dummy’s head outfitted with pressure sensors at various locations. They then placed the head directly underneath a shock tube, which was pressurized with helium until a membrane wall burst, releasing the gas in a shock wave. The helmets were tested with shock waves of varying strength, each corresponding to a different type of German artillery shell exploding from a distance of one to five meters away."
One to five meters? I would think that even the smallest
German WWI artillery shell (7.7 cm) would cause instant death if it exploded one meter over a soldier's head. I'm not sure about five. And that would be through just the shock wave alone, the blast and shrapnel notwithstanding. Some of the larger shells within that range would result in a soldier being effectively vaporized or grievously maimed. But it's all in the physics and given all the variables involved maybe there is a lot here I don't understand.
What I always thought was that in an explosion the shock wave precedes the blast and compresses the air though which it travels to a density greater than that of concrete and that this wave travels at supersonic speed. The shock wave always proceeds the actual chemical blast which typically results in burns. After that comes the puncturing and lacerating effects of the shrapnel. So imagine being clobbered over the head with a cinder block traveling at several thousand meters per second. The shock wave is also why people lose their fingers and hands when mishandling fireworks. There's no shrapnel and it's not the chemical blast. Or at least that's how I understand it.
But could that much energy be dissipated over such a short distance of one to five meters? If not, I don't understand how even the best designed helmet could offer much protection under realistic conditions.
But maybe there are different and less destructive ways of creating a similar shock wave that can then be measured in the lab. Someone with more knowledge in this area will have to explain this to me.