• Advanced materials and nanotechnology: CHIROFRICT and its innovation. Interview to Luigi Gambarotta and Andrea Bacigalupo, professors from the Department of Civil, Chemical, and Environmental Engineering at the University of Genoa

Advanced materials and nanotechnology: CHIROFRICT and its innovation. Interview to Luigi Gambarotta and Andrea Bacigalupo, professors from the Department of Civil, Chemical, and Environmental Engineering at the University of Genoa

May 24, 2024

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Knowledge Share

In the world of advanced materials and nanotechnology, innovation is the key to progress. Today, we have the privilege of introducing two professors from the Department of Civil, Chemical, and Environmental Engineering at the University of Genoa—Luigi Gambarotta and Andrea Bacigalupo. With decades of experience in the mechanical modeling of heterogeneous materials, these researchers have significantly contributed to our understanding of material behavior, especially in seismic responses of masonry constructions and the safety of infrastructure like masonry bridges.

Their journey began in the 1980s, focusing on the damage characterization in quasi-brittle materials, and evolved through the 1990s to enrich the mechanics of masonry structures. As the 2000s approached, their research extended into the mathematical theory of homogenization and the emerging field of mechanical metamaterials, leading to the development of innovative materials with complex microstructures.

In this interview, Professors Gambarotta and Bacigalupo discuss their latest project, CHIROFRICT. Conceived in 2022, this project focuses on a resilient layered metamaterial with unique properties such as maximum energy dissipation, reusable devices without external intervention, and a bilateral response. They delve into the potential applications of CHIROFRICT across various industries, including railway, aerospace, automotive, and seismic constructions, highlighting its capacity to enhance current technologies.

CHIROFRICTS is the most viewed patent on KS platform for the month of April: https://www.knowledge-share.eu/en/patents/chirofrict-elastic-wave-and-shock-mitigation

CHIROFRICT

Can you tell us about your background and role/interests in the research world?

We are two Professors from the Department of Civil, Chemical, and Environmental Engineering at Università di Genova. For several decades, we have been working on the mechanical modeling of heterogeneous materials. In the early 1980s, we focused on characterizing damage in quasi-brittle materials where the presence of microcracks significantly affects deformability and especially resistance.

Later, as civil engineers in the 1990s, we transferred this knowledge to the mechanics of masonry constructions, enriching the state of the art with mechanical models capable of representing the behavior of individual bricks. These studies have had broadly positive impacts on understanding the seismic response of masonry buildings, particularly in historic and monumental structures. The next step was to open new research avenues, leveraging our background on the safety of masonry bridges, which constitute a significant part of the road and railway infrastructure network.

These experiences encouraged us to return to fundamental problems in the mechanics of heterogeneous media. Starting in the 2000s, one major theme was the mathematical theory of homogenization, understood as the formulation of local and non-local physical-mathematical models to determine the equivalent homogeneous elastic characteristics of real composite materials.

These are necessary for the computational solution of static or dynamic problems of structural systems in composite material, which would otherwise be unsolvable with conventional computational means. Subsequently, we found ourselves with important experiences to successfully tackle the emerging topic of mechanical metamaterials combined with the development of Additive Manufacturing.

We developed new metamaterials with complex periodic microstructures, including auxetic behavior, capable of creating highly efficient acoustic meta-filters to filter elastic waves in the material. This was made possible using innovative static and/or dynamic homogenization methodologies in discrete and continuum media. Using materials with multi-physical behavior (e.g., piezo/flexo-electric, magneto-electro-elastic), we achieved optimal design of smart metamaterials with controllable acoustic properties.

Can you briefly introduce the technology? How does it work and how does it improve the status quo of currently used technologies in the field of advanced materials and nanomaterials?

Recently, in 2020, a research group from Sandia Laboratories proposed a pioneering study in which a microstructured material capable of dissipating energy and/or absorbing shocks through a frictional mechanism was developed, with the possibility of recovering the initial configuration at the end of the loading history.

This absolutely innovative topic intrigued us and stimulated us to conceive a resilient layered metamaterial made of auxetic sheets with periodic and chiral microstructures with frictional interface micro-mechanisms.

This resilient metasystem has the following innovative properties: i) hysteretic response with maximum mechanical energy dissipation; ii) reuse of the device without external interventions, restoring the initial configuration at the end of the dynamic process; iii) multi-directionality of the dissipative response; iv) bilateral response, i.e., equal behavior in tension and compression.

The research project for CHIROFRICT: from the idea to market potential.

The conception of CHIROFRICT began in 2022 and was developed with reference to the ideal performance of an unlimited mechanical system, where the dimension of the microstructure is negligible compared to the structural scale. From this study, the significant performances mentioned above emerged.

Currently, studies are underway on scale effects through discrete and continuum analytical/computational modeling, ranging from simple finite systems subjected to cyclic forcing to complex systems representative of anti-vibration and/or shock absorption supports. These results have been validated through a series of virtual experimental tests.

To corroborate the conceived technology, appropriate experimentation on metallic samples in microstructural configurations obtained through suitable parametric and topological optimization techniques of the metamaterial is planned. Based on experimental confirmations, potential technological applications are expected in the following production sectors: railway industry; shipbuilding; aerospace industry; automotive industry; seismic industrial constructions, and road and railway infrastructures.

Among the possible applications, we read both Industry and Shipbuilding ranging from railways to aerospace, passing through automotive and seismic sectors. Do you think it would be possible to further expand the scope of action with the implementation of the research?

The principle on which the invention is based can also be extended to larger scale mechanical systems. It is a mechanism based on elastic portions coupled in mutual frictional contact controlled by appropriately arranged elastic devices. It can be applicable in various industrial and engineering sectors where hysteretic dissipation can play an important role.

Spin-off or no spin-off? If not, why? If yes, with whom? (investors/industrial partners?) How much would it need in economic terms?

The technological realization of the patent certainly requires the involvement of industrial partners and investors, possibly through a spin-off, considering the need, on the one hand, for a confrontation with technological and industrial needs and, on the other hand, financial support for the evolution of the patent up to TRL6.

Were you already familiar with the KS platform? In what context?

The KS platform was a pleasant discovery that further stimulated us. We are counting on the dissemination and development of the patent through this useful platform.

CHIROFRICT

CHIROFRICT

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