Self-Healing: Could Materials That Repair Themselves Be Used in the Aerospace Industry?
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APEX Insight: No need to call the aircraft technician over small dents and cracks. These materials will repair themselves.
The ability for organic beings to heal themselves is such a given – we rarely give it a second thought. Researchers, however, have. They’re taking cues from Mother Nature and coming up with ways for synthetic materials to replicate this behavior. For the aerospace field, it’s a potentially industry-changing innovation. Just imagine: a cracked airplane wing that can fix itself mid-flight without human intervention, or a seat cover that doesn’t need to be removed to be repaired.
In 2015, a team of researchers out of the University of Bristol in the United Kingdom created a wing made of a carbon fiber composite embedded with microscopic beads. On impact, the tiny capsules release a liquid that can seep into a crack and harden, as a result of a catalytic reaction, restoring the wing to nearly full capacity. The idea is akin to when we cut ourselves. Blood fills the wound, hardens and creates a scab. Soon enough we’re good as new. Lead researcher Duncan Wass clarifies, however, that this technology would only work for tiny cracks. “But micro-cracks can lead to catastrophic failures,” he told the BBC.
Imagine: a cracked airplane wing that can fix itself, or a seat cover that doesn’t need to be removed to be repaired.
Researchers at RMIT University in Melbourne have devised a similar technology for wings and fuselage made of carbon fiber sheeting. In their model, small polymer capsules are embedded in the sheeting so that when a crack develops, the polymer melts and fills the fissure with resin. Notably in the RMIT model, the polymer can be used multiple times while retaining its original performance, researcher Chun Wang told the Australian Broadcasting Corporation.
Self-healing principles in the aerospace field aren’t solely restricted to aircraft exteriors. Melik Demirel, professor of Engineering Science and Mechanics at Penn State University, and his team have developed a liquid coating made from bio-synthesized squid ring teeth that can be used to turn a variety of textiles – from nylon and synthetics to natural fibers – into self-healing ones. It uses water to bind the torn piece of fabric back together. Demirel’s team is looking into how heat and light can serve this function, too.
Demirel explains that beyond self-healing, the material can also be used for heat management – it absorbs heat, which could be mighty nice if you’re sitting in an airplane for 12 hours. “During a long trip, your body temperature needs to be cooled off,” he says. “A seat that has this textile is a better seat.”
“Self-Healing” was originally published in the 8.1 February/March issue of APEX Experience magazine.