Composite metal foams provide armor protection for one third the weight and make super car bumpers

Stainless steel composite metal foam can replace rolled homogeneous steel armor with the same protection for one-third of the weight.

According to the material’s inventor the material would make a great bumper, as the sponginess of the metal foam soaks up impact energy. Raibei claims that for a passenger sitting in a car outfitted with a composite metal foam bumper, a collision at 28 miles an hour will feel like a 5 mile per hour collision. This gives a hint as to how effective it is in soaking up the energy of a rifle bullet—or even a tank round.

Composite metal foam can block fragments but also the blast waves that are responsible for trauma such as major brain injuries. That would reduce vehicle weight significantly, improving fuel mileage and vehicle performance.

New research from North Carolina State University and the U.S. Army’s Aviation Applied Technology Directorate shows that stainless steel composite metal foam (CMF) can block blast pressure and fragmentation at 5,000 feet per second from high explosive incendiary (HEI) rounds that detonate only 18 inches away.

Researchers fired a 23×152 millimeter (mm) HEI round – often used in anti-aircraft weapons – into an aluminum strikeplate that was 2.3 mm thick. 10-inch by 10-inch steel-CMF plates – either 9.5 mm or 16.75 mm thick – were placed 18 inches from the aluminum strikeplate. The researchers assessed that the steel-CMF held up against the wave of blast pressure and against the copper and steel fragments created by the exploding round, as well as aluminum from the strikeplate.

Next steps include testing the steel-CMF against improvised explosive devices (IEDs) and high-caliber, mounted ballistics. The researchers have already tested the CMF’s performance against hand-held assault weapons, radiation and extreme heat.

A test video shows a M2 armor-piercing bullet smashing into the foam and destroying itself on impact. In the video, recorded with a high speed camera, the bullet initially makes a small crater in the material but then appears to vaporize.

Composite metal foams could be used to create body armor for soldiers, and used on vehicles from navy ships to armored vehicles as a lightweight alternative to steel plate. The result would be a more agile, better protected military.

Composite Structures – A study on blast and fragment resistance of composite metal foams through experimental and modeling approaches

Composite metal foam (CMF) is known for its high strength to density ratio and extraordinary energy absorption capabilities. In this study, stainless steel CMF panels are manufactured and tested against high explosive incendiary (HEI) rounds to study their resistance against explosive blast pressure and the resulting fragments. It is shown that the CMF panels were able to stop the imparted fragments of various sizes, with speeds up to 1500 m/s, and absorb the blast energy without cracking or bowing. The experimental findings were verified using IMPETUS Afea Solver and compared to the performance of a conventional aluminum armor. It is observed that despite their similar mass, the depth of penetration of the fragments into the aluminum plate is higher than that of the CMF panel. Significant front petaling and bulging is observed in aluminum plate following impact of the blast and frags. No petaling and minimal bulging is observed in all CMF panels. In addition, CMF panels are far less stressed when compared to the aluminum plate at any interval following the blast. The experimental and analytical results are proving that novel CMF material can be the solution for the pressing need for light-weight and more efficient vehicular armors.