Title:

Quasi-periodic metamaterials: from vibration control to failure-resistance

Speaker:

Dr. Dr. Matheus Inguaggiato Nora Rosa

Affiliation:

ETH Zurich

When:

Thursday, February 13, 2025 at 11:00:00 AM   Add to Calendar

Where:

GTMI Building, Room 114

Host:

Dr. Julien Meaud
julien.meaud@me.gatech.edu

Abstract

Metamaterials are engineered assemblies that exhibit properties not found in the individual constituents. Moving beyond traditional designs that rely on the periodic repetition of a single unit cell, this talk will describe the unique dynamics and mechanical properties of quasi-periodic metamaterials. First, I will discuss the vibration control capabilities of quasi-periodic elastic materials with modulated properties, including spatial variations in stiffness, material inclusions, and geometric features. A series of numerical and experimental results illustrate the ability to manipulate bandgaps (frequency attenuation bands), localized vibration modes, and wave propagation characteristics. These results highlight the remarkable control over the propagation and confinement of elastic waves and mechanical vibrations, accomplished through relatively simple and cost-effective modifications to otherwise uniform periodic patterns. The second part of the talk will focus on some of the exciting characteristics of quasi-periodic metamaterials subject to large deformations. I will show how these materials can tackle the challenge of combining stiffness and deformability under large strains in low-density designs. Such structures often rely on slender elements, like thin beams or plates, which are prone to buckling instabilities when arranged in periodic, stiffness-optimized configurations that support loads through uniform stress distributions. Consequently, many state-of-the-art metamaterials underperform in large deformation regimes. In contrast, the proposed quasi-periodic designs feature non-uniform stress distributions that simultaneously promote stiffness and stable deformations, leading to exceptional failure resistance. Numerical and experimental studies demonstrate these novel properties under quasi-static conditions, and suggest how similar design principles could be applied to dynamic large deformation events, such as impacts and blasts.

Biography

Dr. Matheus I. Nora Rosa is a Postdoctoral Researcher at ETH Zurich, working with Prof. Dennis Kochmann in the Mechanics & Materials Laboratory. He earned his MSc and PhD in Mechanical Engineering from the Georgia Institute of Technology and the University of Colorado Boulder, respectively, both under the supervision of Prof. Massimo Ruzzene. Dr. Rosa's research aims to understand and harness the unique properties of unconventional materials towards innovative applications in mechanics, acoustics, vibrations and wave propagation. His doctoral work contributed to the design of periodic, quasi-periodic and disordered metamaterials that precisely manipulate elastic and acoustic waves, with potential applications in vibration attenuation and noise control, energy harvesting, and information processing in small-scale devices. At ETH Zurich, his current research emphasizes the development of lightweight quasi-periodic metamaterials with enhanced failure resistance under large deformations—an essential characteristic for applications in elastic energy absorption and impact mitigation.

Notes

Refreshments will be served.