Aircraft could soon be covered in new technological cobwebs. Inspired by the gossamer strands of spider webs, scientists from Stanford University have created an ultra-fine mesh of strain and temperature sensors.
Wrapped around an aircraft, the sensors could help craft monitor their internal well-being. This added awareness could prevent microscopic cracks from developing into catastrophic failures. Beyond aircraft, the new technology could create a new breed of intelligent automobiles, packaging and medical devices.
"We want to make airplanes that fly like birds," said Fu-Kuo Chang, a scientist at Stanford University who developed the sensors and co-authored a recent article about the technology in the journal, Advanced Materials. "Aircraft that have all the sensing information about what is happening around them, just like birds do."
Aircraft and birds both have various ways to sense their environment. Birds have eyes to see, ears to hear and mouths to speak (or sing). Aircraft have their own versions of these organs, such as radar, which gathers information about the physical environment, and radio, which allows them to communicate.
But aircraft lack nerves. Unlike birds, they don't have a way to sense tiny changes inside their bodies. For instance, a bird in a dive can sense, through its nerves and other tissues, whether the strain is too great and if they need to pull up before their bones break.
The new spider web-inspired mesh would give aircraft two new senses birds have had for millions of years: strain and temperature. The new mesh contains tiny structures that can, say, measure the temperature along the entire body of the aircraft, or map the air pressure flowing around a wing.
The new sensor is a plastic polymer that has the gold sensors laid down on top of it, which monitor the skin of the aircraft. The Stanford scientists are already developing technology that will allow pilots to image the interior of their aircraft similar to the way pregnant women can see their unborn children.
By adding ultrasonic wave-inducing piezoelectric devices, pilots could constantly scan the aircraft to discover, say, microscopic cracks in the supports long before they developed into life-threatening failures.
"This will help ensure the safety of air transportation," said Frank Chang, a scientist at the University of California, Los Angeles who is familiar with the research but is not involved in it.
To paper an entire aircraft with sensors would ordinarily add significant weight, and therefore require more fuel, something airlines are anxious to avoid. To get around this problem the California scientists stripped the sensors down to the bare minimum of material, eliminating 99.7 percent of it.
When the mesh is initially created it doesn't look like a spider web. But pull on the sides and the material can expand more than 265 times its original size, creating an almost invisible mesh of wires that are nonetheless strong and and durable. One square foot of the material could easily stretch far enough cover an entire car, said Stanford University's Chang.
Spider web-like sensors that can detect touch and temperature in aircraft are just the beginning, say the scientists. The new sensors could eventually lead to smarter cars, wound dressings that tell doctors how quickly a patient is healing, shirts that allow pregnant women to see their unborn child whenever they want, or even synthetic skin for robots.
"This will have very extensive usage and importance," besides just aircraft, said UCLA's Chang.