UVA Studies "Memory Metal" to Minimize Earthquake Damage
A major earthquake hit eastern Turkey in January, killing more than forty people and injuring hundreds more. At the University of Virginia, the news was of special concern to one professor who hopes to make the world safer for those who live in seismic areas.
Earlier this year an earthquake that registered 6.8 on the richter scale killed 41 people in Turkey. It also did serious damage to more than a thousand buildings.
At UVA, Engineering Professor Osman Ozbulut has spent 15 years studying a new building material that could protect structures in the event of a quake. It’s known as memory metal, muscle wire or shape memory alloys. The best known of these is made from nickel and titanium – lightweight, strong and smart.
“What makes this material smart compared to the other materials is the fact that they can remember their original shape. Even if you apply a huge force on them, they can come back to their original shape,” he explains.
And when it’s under pressure, memory metal diffuses pressure – converting it to heat. Often after a quake officials won’t let people go back to their homes, because they fear structural damage might make that unsafe, but by measuring the temperature of smart metal, Ozbulut predicts inspectors could more accurately assess risk – sparing some from the misery of homelessness.
So far these alloys have been used to make smaller structures for aerospace and medicine – things like stents, bone plates or resilient frames for glasses. It’s hard to make bigger things like structural beams – and expensive, so engineers at UVA are trying something else.
“Our focus right now is on SMA cables which are made of individual small-diameter wires combined together to get a large diameter structural elements,” Ozbulut says.
In his lab, Ozbulut is testing those cables and crafting devices that can not only absorb earthquake energy but return a building to its original state afterward. He knows of several demonstration projects and one long-term structure where memory metal is already in use -- a bridge in Seattle.
Someday, Ozbulut hopes more smart metal will be used in his hometown – the epicenter of the earthquake in Turkey and the city where he was born.