US Air Force Has a Breakthrough Material

The US Air Force Research Lab has a new material that reacts to a shock wave like a one-way switch. The foam-like structure that contains a series of specifically-engineered tiny holes that determine the overall behavioral characteristics.

Above – An Air Force Research Laboratory research team has developed a 3-D printed polymer-based foam structure that responds to the force of a shock wave to act as a one-way switch. These images show the material’s formation of jets, which localize shock wave energy in one direction, but not the other. (U.S Air Force photo illustration)

Over a period of months, AFRL experts used computer modeling to run trials to determine the most effective hole geometries to achieve the desired material response. When they would arrive at a promising configuration, Spowart says the team would print a small test article, a flat plate not much bigger than a pencil eraser. With the help of Los Alamos National Laboratory, working on-site at the Dynamic Compression Sector user facility at Argonne National Laboratory, they would then conduct tests and image the specimen using X-rays to determine performance.

From there, the AFRL team would review results and fine-tune the material configuration to further refine the product through additional modeling and testing. Spowart described the end product as containing a series of hollow cones. When these cones encounter a shock wave, they collapse inward, forming jet protrusions that project from the opposite side. These jets localize the shock wave energy, which is the origin of the material’s unique directional behavior.

Spowart says this effort represents a significant breakthrough in materials engineering.

“The materials technology came from AFRL,” he said, crediting the modeling and materials expertise of the project team. “The testing facilities and test methodology came from Los Alamos. So when you put the two things together, you get a really good team.”

He adds that the remarkable test imaging provided by Argonne National Laboratory was crucial in proving out the concept. He explained that the laboratory’s Advanced Photon Source synchrotron is a unique piece of equipment that fires a very powerful and concentrated X-ray beam at the test article, allowing frame-by-frame imaging of a shock wave penetrating the specimen, all of which occurs within a few nanoseconds.

“This new imaging capability, together with the new manufacturing technology and computer simulations, allowed the team to obtain images and evaluate concepts in ways that were well beyond reach just a few years ago,” said AFRL Senior Mechanical Engineer and team member Dr. Christopher Neel.

“The Dynamic Compression Sector is a unique facility that enables in-situ imaging of dynamic events giving us unprecedented information of the microstructural effects on dynamic behavior,” added Los Alamos National Laboratory scientist Brittany Branch, who led the dynamic experiments. “Traditional shock compression diagnostics would not elucidate the localization phenomena that is occurring during shock compression. We would see a difference in shock velocity with traditional techniques, but not understand why. These experiments were very exciting, since we demonstrated a shock diode for the first time.”

Spowart said the team plans to publish their findings and work toward transitioning the technology for further maturation and integration into existing systems, where he believes this technology has tremendous potential. “We are very excited about this effort and the teamwork that made it possible. This is great example of what basic research can do to strengthen our capabilities.”

18 thoughts on “US Air Force Has a Breakthrough Material”

  1. I don’t understand what you mean. Is it that shock wave velocity is anisotropic?

  2. You don’t need a meta-material to do that. This stuff’s amazing characteristic is that it propagates shock waves differently in opposite directions.

  3. A very good application for Space Protection from high velocity meteorites and micro-meteroites. Could be designed with inject liquid for self-healing, and could go even further on self-protection.

  4. Other than the ideas posited by others here, I can think of any further uses but that doesn’t change the fact that this is pretty darn cool.

  5. Wonder if it could somehow be used in a combustion engine, reaction engine or Stirling engine.

  6. Naive idea: Could this be used to stop brain injuries in soldiers who are near IEDs but not hit by shrapnel?

  7. Computerized reactive armor. A layer of sensors, actuators and super capacitor banks that would sense an incoming projectile and project a pillar of material at it.

  8. Possibly for making a bullet-proof drone, but the more likely candidate seems a meteorite proof space vehicle, satellite, or space station.

  9. I think it converts the kinetic energy of a shock wave into thermal energy by creating turbulence in the media the wave is propagating in.
    I’d guess a “thin” sheet of this, particularly if held a meter or so from a structure would offer protection. If a large fraction of the kinetic energy is converted to thermal, to the foam itself might explode.

  10. I worked on a project to add blast resistance to the operator shacks at refineries. This would be a very welcome addition to the protection they have now.

  11. “According to AFRL Senior Materials Research Engineer Dr. Jonathan Spowart, this novel material configuration, although in the early stages of development, has the potential to be scaled up in order to be used in different ways for a variety of applications, including for the protection of structures.”

  12. Let’s see, the selling point is you have a material here which propagates shock waves in one direction, and extinguishes them in the other. A sort of shock wave diode.

    A basic demonstration of meta material effects for shock waves.

    I could see it used in shock wave shaping for complex explosives applications. Possibly more compact shaped charges.

  13. I’d guess based on the shape of the shock front in the pics that a high power blast would deform things that may otherwise survive if the load is spread evenly.

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