Damaged Structural Materials Can Self Heal

Wednesday, December 8, 2010 @ 06:12 PM gHale


There is now a material in development that may be able to not only sense damage in structural materials, such as cracking in a fiber-reinforced composite, but even heal it.
The aim of developing “autonomous adaptive structures” is to mimic the ability of biological systems such as bone to sense the presence of damage, halt its progression, and regenerate itself.
This autonomous material uses “shape-memory” polymers with an embedded fiber-optic network that functions as the damage detection sensor and thermal stimulus delivery system to produce a response that mimics the advanced sensory and healing traits shown in biological systems, said Henry Sodano, a researcher at Arizona State University. An infrared laser transmits light through the fiber-optic system to locally heat the material, stimulating the toughening and healing mechanisms.
The material system is capable of increasing the toughness of a specimen by 11 times, Sodano said.
After toughening the specimen, the crack can close using the shape-memory effect to recover a 96 percent of the object’s original strength. In fact, after the crack closes, the new material is nearly five times as tough as the original specimen, even though the material has gone beyond past its original failure strain point by a factor of four. The material and healing process can begin while the structure is in operation, which has not been possible with existing healing techniques.



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