IIT Mandi develops metamaterial for earthquake-resistant buildings

Can a building foundation consisting of repeating circular scatterers made of steel and lead embedded in a rubber matrix make that structure earthquake proof?

A study conducted by a team of researchers from the Indian Institute of Technology, Mandi, suggests so. The team, lead by Dr Arpan Gupta, Associate Professor, School of Engineering, IIT Mandi, proposes a two dimensional metamaterial-based foundation built in the above mentioned manner for protecting buildings against earthquakes. The researchers say the investigation of meta-materials for seismic waves is a relatively new and highly complex field. If proven successful, the research could lead to significant advances in earthquake protection.

The researchers used a computer model to test the concept of a 2D-metamaterial-based foundation for earthquake protection. The computer model of the foundation along with the building structure was subjected to earthquake excitations. Two cases were considered- concrete foundation and metamaterial foundation. In the case of concrete foundation, large vibrations were recorded, while in the case of metamaterial foundation - very minimal vibrations were observed, the researchers say.

"By intelligently designing the foundation of the building, the earthquake waves can be diverted/reflected back, without causing much damage to the building. Any building requires a good foundation, but the key here is to have periodicity in the foundation design, and this is known as Metamaterial Foundation. Such periodic variation of material properties can lead to reflection of waves thereby protecting the building structure on that foundation," Dr. Gupta says.

"Our work shows the potential of metamaterials to provide seismic protection to structures. We hope that our research will inspire other researchers to explore the possibilities of metamaterials in other areas of structural engineering and earthquake resistant buildings," he adds.

A metamaterial is created by assembling multiple elements made from composite materials like metals and plastics, usually arranged in repeating patterns that are smaller than the wavelengths of the phenomena they affect, such as earthquake vibrations or seismic waves. Seismic waves are elastic waves that transport energy through the Earth's layers. Unlike other types of physical waves, seismic waves have long wavelengths and low frequencies.

The details of the research have been published in the journal Scientific Reports on February 9, 2023.