Research interests:

I am interested in both the theoretical and application sides of my field of study. My interests include structural and mechanical systems, structured materials, dynamics, mechanics, wave propagation, and their applications, particularly in soft robots, deployable structures, and reconfigurable structures. Below are short summaries of some of my recent and ongoing research.

Research topics:

Soft Multistable Metamaterials (Ongoing since 2017)

In this ongoing research, we focus on the dynamics of materials with dissipative multistable microstructures exhibiting strongly nonlinear waves causing structural transition. We established a testable theory – with explicit analytical solutions – to predict the behavior of a one-dimensional system under various geometrical and material properties, independent of excitation [J5]. We further introduced continuum descriptions for a variety of substrate-free dissipative reconfigurable metamaterials in 2D and 3D and developed numerical tools for modeling nonlinear waves in these structures [J6]. Acquiring inspiration by phase-field models in crystalline solids, we fabricated and characterized one- and two-dimensional auxetic multistable metamaterials and utilized a continuum mechanical model to describe these structures, which in the presence of defects, was shown to redirect or pin transition waves, as well as to split, delay, or merge propagating wavefronts [J4].

This work is funded by the Army Research Office and is in collaboration with Prof. Dennis M. Kochmann (PI), ETH Zürich; Prof. Ahmad Rafsanjani, University of Southern Denmark; Prof. Katia Bertoldi, Lishuai Jin, Jochen Muller, Harvard; and Vincent Tournat, CNRS.

Mechanical Metamaterials/Systems (Ongoing since 2018)

In this research, we focus on studying structural analogs of atomic-level phenomena in materials such as domain patterning, domain nucleation, and domain wall motion under an applied bias. We can demonstrate a quantitative analogy between these mechanical systems and material-level phenomena via a homogenized continuum description. More on this topic in the near future.

This work is funded by the Army Research Office and is in collaboration with Prof. Dennis M. Kochmann (PI), ETH Zürich; and Prof. Michael J. Frazier, University of California, San Diego.

Nonlinear Dispersive Elastic Waves (Ongoing since 2012)

We made fundamental contributions to the fields of nonlinear elastic/acoustic metamaterials and gained extensive experience in the areas of solid mechanics, vibrations, and dynamics. We developed a closed-form mathematical framework for the analysis of wave dispersion and harmonic generation in elastic media incorporating finite strains, as well as nonlinear constitutive relations. In particular, we investigated the intrinsic harmonic generation mechanisms in elastic solid media and established connections with the derived dispersion relations [U2]. We also established exact analytical formulations for wave dispersion considering the effects of geometric and material nonlinearities in elastic media and derived analytical spatial solutions for nonlinear elastic waves in 1D homogeneous solids using high-order perturbation theory.

Using the developed framework, we extended the analysis to the derivation of approximate formulations for periodic media and locally resonant metamaterials, extending the field of acoustic/elastic metamaterials [J1] and phononic crystals [J3] to the nonlinear regime, and, in doing so, provided opportunities for the design and engineering of new types of materials and devices.

This work is funded by the National Science Foundation and is in collaboration with Prof. Mahmoud I. Hussein (PI), University of Colorado Boulder.

Dispersive Lattice Metamaterials (2015-2016)

In this research, we focused on plane wave propagation in dissipative lattice metamaterials and studied the effects of damping on the isofrequency dispersion curves. Furthermore, we investigated the possibility of engineering the dissipation anisotropy by tuning the directional properties of the underlying damping [J2].

This work was funded by the National Science Foundation and was in collaboration with Prof. Mahmoud I. Hussein (PI), Dimitri Krattiger, and Clemente Bacquet, University of Colorado Boulder.