Tough humanmade rubbers for future Soldier protection systems
Researchers show materials strengthen on their own when impacted at very high speed
Army and MIT researchers advanced a unique experimental device to better test the durability of high performance and robust polymeric materials that appear to strengthen themselves under attack by rapid impact.
Army Research Laboratory’s Dr. Alex Hsieh, along with Prof. Keith A. Nelson, Dr. David Veysset and Dr. Steven Kooi, from the Army’s Institute for Soldier Nanotechnology at MIT, discovered that when targets made of poly(urethane urea) elastomers or PUUs are impacted at very high speed by micro-particles made of silica, the PUU target shows hyperelastic behavior. That is, they become extremely stiff when deformed at strain rates on the order of 108/s ? which means roughly that the material of the target deforms to half of its original thickness in an extremely short time equal to one second divided by hundred millions. PUUs also bounce back after the impact, said Hsieh.
The test device uses a pulsed laser to shoot micrometer-sized bullets at targets made of PUUs. Researchers found, for the first time, “behaviors that contrast greatly to the impact response observed in a cross-linked polydimethylsiloxane elastomer where micro-particles penetrated the target and the target material did not bounce back or completely recover.”
Комментариев нет:
Отправить комментарий