Engineers have borrowed a technique from shellfish to build a pre-stressed form of glass that can bend rather than break.
As anyone who has dropped their phone from a height knows, glass has a tendency to fracture when struck. But boffins at McGill University's department of mechanical engineering have developed a new form of glass that is pre-cracked by lasers, with the resulting tiny fissures being filled with polyurethane to make the substance capable of bending on impact.
"What we know now is that we can toughen glass, or other materials, by using patterns of micro-cracks to guide larger cracks, and in the process absorb the energy from an impact," said Professor François Barthelat.
"We chose to work with glass because we wanted to work with the archetypal brittle material. But we plan to go on to work with ceramics and polymers in future. Observing the natural world can clearly lead to improved man-made designs."
The inspiration from the design came from 20 years of research into the mystery of mollusk shells, which are mostly made up of brittle chalk but are still strong enough to withstand serious pressure. Shellfish use flexible connections to achieve this strength, and the engineers have been able to replicate this with glass.
"Compared with standard glass, which has no microstructure and is brittle, our bio-inspired glass displays built-in mechanisms that make it more deformable and 200 times tougher," the team reports in the journal Nature Communications.
"This bio-inspired approach, based on carefully architectured interfaces, provides a new pathway to toughening glasses, ceramics or other hard and brittle materials." ®