Scientists have created a new type of blast-resistant glass that is thinner, lighter and less vulnerable to small-scale explosions than existing glass.

In tests, the improved glass design has been shown to withstand a hand grenade-strength bomb explosion originating close to the window panel. The blast caused the glass panel to crack, but didn’t puncture the composite layer.

{{ video="LS_090910_blast-resistant-glass" title="Blow it Up: This Glass Can Take It" caption="University of Missouri researchers are developing and testing a newrntype of blast-resistant glass that will be thinner, lighter and lessrnvulnerable to small-scale explosions. Credit: University of Missouri" }}

Blast-resistant glass windows are often installed in federal buildings and other vulnerable structures as a safety measure against potential terrorist attacks. However, they are thick and expensive to manufacture.

“The glass we are developing is less than one-half of an inch thick. Because the glass panel will be thinner, it will use less material and be cheaper than what is currently being used.” said Sanjeev Khanna, a professor of mechanical and aerospace engineering at Missouri University.

Conventional blast-resistant glass is comprised of a layer of strong plastic sandwiched between two sheets of laminated glass. The new design is built stronger and thinner by replacing the plastic layer with a transparent composite material made of glass fibers embedded in plastic. The glass fibers are only about half the thickness of a typical human hair (25 microns), and leave less room for defects in the glass that could lead to cracking.

The use of a transparent composite interlayer gives researchers the flexibility to change the strength of the layer by changing the glass fiber quantity and its orientation, Khanna said.

The researchers plan to perform similar tests on larger pieces of glass that are similar to standard window sizes. They’d also like to see how well the glass fares when subjected to large-scale explosions.

“The new multilayered transparent glass could have a wide range of potential uses if it can be made strong enough to resist small-scale explosions,” Khanna said. “The super-strong glass also may protect residential windows from hurricane winds and debris or earthquakes. Most hurricane damage occurs when windows are punctured, which allows for high-speed wind and water to enter the structure.”