About

Katia Bertoldi is the William and Ami Kuan Danoff Professor of Applied Mechanics at Harvard University, affiliated with the Harvard John A. Paulson School of Engineering and Applied Sciences. Her primary teaching areas include Materials Science and Mechanical Engineering. Her research focuses on applied mathematics, modeling physical and biological phenomena and systems, applied physics, and materials science, particularly in the context of solid mechanics. She is involved in exploring the physics of squeaks in rubber sneakers, the development of textiles with adjustable aerodynamic properties, and innovative approaches to programming robots using rubber bands. Her work integrates interdisciplinary methods to advance understanding in materials and mechanical engineering, contributing to both theoretical insights and practical applications.

Research topics

• Computer Science
• Materials science
• Physics
• Composite material
• Engineering
• Mathematics
• Mechanical engineering
• Nanotechnology
• Structural engineering
• Optics
• Artificial Intelligence
• Geometry
• Mathematical analysis
• Biological system
• Quantum mechanics
• Aerospace engineering
• Biology
• Paleontology
• Oceanography
• Electrical engineering
• Chemistry
• Geology
• Classical mechanics
• Optoelectronics

Selected publications

• Conformal Elastodynamics in 2D Dilational Metamaterials

  arXiv (Cornell University) · 2026-04-17

  preprintOpen access

  Flexible mechanical structures can undergo large deformations under small loads, enabling large, complex, and nonlinear wave responses under finite-frequency driving. Here, we study a dynamically driven canonical flexible mechanical metamaterial composed of rigid squares connected at their corners by flexible hinges. This metamaterial supports a uniform dilational mechanism and, in the limit of ideal joints, exhibits a Poisson ratio of -1. The presence of this dilational mode of deformation gives rise to a conformal symmetry, in which the dynamics are approximately invariant under a wide class of physical transformations -- conformal maps. We find that the low-frequency response of the system is dominated by conformal deformations consisting of spatially varying rotations and dilations concentrated at the boundary. Even at high frequencies, each conformal map implies a conserved spatially complex momentum. We explore how experimental parameters such as material stiffnesses and the geometry and number of unit cells allow experimental conformal momenta to approach this conservation, varying slowly compared to the non-conformal momenta of same order. These results constitute a new framework opening fundamental avenues for the study of conformal wave phenomena in dilational metamaterials as well as potential strategies for controlling nonlinear waves and vibrations.

  PublisherDOI

• Conformal Elastodynamics in 2D Dilational Metamaterials

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-01

  datasetOpen access

  Post-processing of all data in this dataset were completed using the code dynamic-conformal-metamaterials developed for the paper. This dataset can be loaded and analyzed using dynamic-conformal-metamaterials with the following steps: Install dynamic-conformal-metamaterials. Download data.zip from this dataset. Extract data.zip and place its content in the repository's root folder. Load the data associated with each analysis shown in the paper using the notebooks. Run cells in notebooks>nonlinear_notebooks>dynamics_of_conformal_metamaterials.ipynb to generate and save all reaction force data prior to running any cells in linear_notebooks and/or conformalanalysis_notebooks

  PublisherDOI

• Transition Waves in Mechanical Metamaterials with Neighbor-Programmable Energy Landscapes

  HAL (Le Centre pour la Communication Scientifique Directe) · 2026-03-10

  preprintOpen accessSenior author

  Transition waves in mechanical metamaterials manifest themselves as propagating interfaces between different stable states in lattices composed of arrays of coupled, intrinsically bistable elements. Here, we show experimentally and numerically that arrays of elastic unit cells that are individually monostable, yet whose energy landscapes can be programmed through interactions with neighboring units, provide a rich and largely unexplored platform for transition wave propagation. We implement this concept by designing a unit cell comprising a von Mises truss supported by two vertical elastic beams. In one-dimensional arrays of such units, we demonstrate that each cell's energy landscape can change from monostable to bistable depending on the state of its neighbors. This neighbor-programmable energy landscape enables the controlled initiation and propagation of transition waves, giving rise to highly discrete, directionally unbiased, domino-like wave propagation. Experiments and numerical simulations show that the existence and speed of the waves are governed by geometric design and mass distribution. Our results establish neighboring effects as a distinct mechanism for transition wave propagation, expanding the design space of mechanical metamaterials beyond architectures that rely on intrinsically multistable building blocks.

  PublisherOA PDFDOI

• Squeaking at soft–rigid frictional interfaces

  Nature · 2026-02-25 · 3 citations

  articleOpen accessSenior author
  PublisherOA PDFDOI

• Built to Die: Bioinspired Locomoting Robot with Programmed End-of-Life Biodegradation

  2026-04-07

  article

  In a world where engineering innovation is growing in parallel with pollution and climate changes caused by its byproducts, researchers face an increasing urgency to develop new materials and systems that are environmentally friendly. While many robots have historically been designed to perform challenging or dangerous tasks in remote environments, deployed robots will contribute to pollution if they are lost or not retrieved in full. In this work, we propose a design scheme for replacing synthetic components of a known soft robot with entirely biodegradable alternatives to demonstrate the opportunities for systems that can be deployed without concern for robot failure or retrieval. Additionally, our robot demonstrates programmable end-of-life biodegradation, in this case when in contact with water. Our robust yet biodegradable robot remains operable for days under standard conditions. Upon contact with the programmed stimulus, water, the robot ceases operation and begins degrading, allowing future on-board payloads to be selectively deposited into a water-rich area. This robot demonstrates critical components for our long-term vision of future robot designs that can be rapidly prototyped and deployed to complete tasks autonomously without consideration for post-operation collection and failure contingencies.

  PublisherDOI

• Transition Waves in Mechanical Metamaterials with Neighbor-Programmable Energy Landscapes

  arXiv (Cornell University) · 2026-03-10

  articleOpen accessSenior author

  Transition waves in mechanical metamaterials manifest themselves as propagating interfaces between different stable states in lattices composed of arrays of coupled, intrinsically bistable elements. Here, we show experimentally and numerically that arrays of elastic unit cells that are individually monostable, yet whose energy landscapes can be programmed through interactions with neighboring units, provide a rich and largely unexplored platform for transition wave propagation. We implement this concept by designing a unit cell comprising a von Mises truss supported by two vertical elastic beams. In one-dimensional arrays of such units, we demonstrate that each cell's energy landscape can change from monostable to bistable depending on the state of its neighbors. This neighbor-programmable energy landscape enables the controlled initiation and propagation of transition waves, giving rise to highly discrete, directionally unbiased, domino-like wave propagation. Experiments and numerical simulations show that the existence and speed of the waves are governed by geometric design and mass distribution. Our results establish neighboring effects as a distinct mechanism for transition wave propagation, expanding the design space of mechanical metamaterials beyond architectures that rely on intrinsically multistable building blocks.

  PublisherOA PDF

• Conformal Elastodynamics in 2D Dilational Metamaterials

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-01

  datasetOpen access

  Post-processing of all data in this dataset were completed using the code dynamic-conformal-metamaterials developed for the paper. This dataset can be loaded and analyzed using dynamic-conformal-metamaterials with the following steps: Install dynamic-conformal-metamaterials. Download data.zip from this dataset. Extract data.zip and place its content in the repository's root folder. Load the data associated with each analysis shown in the paper using the notebooks. Run cells in notebooks>nonlinear_notebooks>dynamics_of_conformal_metamaterials.ipynb to generate and save all reaction force data prior to running any cells in linear_notebooks and/or conformalanalysis_notebooks

  PublisherDOI

• Conformal Elastodynamics in 2D Dilational Metamaterials

  arXiv (Cornell University) · 2026-04-17

  articleOpen access

  Flexible mechanical structures can undergo large deformations under small loads, enabling large, complex, and nonlinear wave responses under finite-frequency driving. Here, we study a dynamically driven canonical flexible mechanical metamaterial composed of rigid squares connected at their corners by flexible hinges. This metamaterial supports a uniform dilational mechanism and, in the limit of ideal joints, exhibits a Poisson ratio of -1. The presence of this dilational mode of deformation gives rise to a conformal symmetry, in which the dynamics are approximately invariant under a wide class of physical transformations -- conformal maps. We find that the low-frequency response of the system is dominated by conformal deformations consisting of spatially varying rotations and dilations concentrated at the boundary. Even at high frequencies, each conformal map implies a conserved spatially complex momentum. We explore how experimental parameters such as material stiffnesses and the geometry and number of unit cells allow experimental conformal momenta to approach this conservation, varying slowly compared to the non-conformal momenta of same order. These results constitute a new framework opening fundamental avenues for the study of conformal wave phenomena in dilational metamaterials as well as potential strategies for controlling nonlinear waves and vibrations.

  PublisherOA PDF

• Harnessing Oscillatory Dynamics for Reprogrammable Mechanical Functionality

  Advanced Functional Materials · 2026-04-01

  articleSenior author

  ABSTRACT Achieving true mechanical reprogrammability — where structural functions can be dynamically defined, modified, and accessed on demand — requires the ability to arbitrarily set and alter the states of arrays of mechanical bits. Here, we introduce a new approach that accomplishes exactly this by exploiting asynchronous symmetry breaking in oscillator arrays driven by a single global actuator. Using an array of pendula as an experimental model, we show that intrinsic frequency separation enables arbitrary information writing and even makes possible the realization of a mechanical piano. Because the system is controlled exclusively through the timing of a global actuation signal, this strategy offers a scalable and efficient route toward reprogrammable matter, with applicability across elastic structures, chemical oscillators, and electronic circuits.

  PublisherDOI

• Twisting-Induced Instabilities in Double-Helix Chiral Rods

  Physical Review Letters · 2025-06-03 · 1 citations

  articleSenior author

  Elastic rods exhibit complex, nonlinear mechanical behaviors, especially under combined axial tension and twisting. Our study focuses on the nonlinear response of double-helix chiral rods, structures that combine a cylindrical core with helically coiled reinforcements. Through experiments, analytical modeling, and finite element simulations, we reveal that twisting induces mechanical instabilities, leading to complex deformation patterns. These instabilities are heavily influenced by the interplay between the core and the helical reinforcements, with the resulting deformations showing strong sensitivity to geometric and material characteristics. The findings enhance our understanding of chiral rods, with potential applications in soft robotics and tunable optical devices.

  PublisherDOI

Recent grants

• DMREF: Biologically Inspired Optimized Materials And Technologies Transformed by Evolutionary Rules (BIOMATTER)

  NSF · $1.6M · 2015–2019

• CAREER: BuckliOrigami: Soft, Active and Foldable Structures Through Instabilities and Large Deformation

  NSF · $400k · 2012–2017

• Collaborative Research: Programming Non-Linear Waves in Compliant Mechanical Metamaterials

  NSF · $414k · 2021–2024

• DMREF: Hydrogel-actuated cellular soft robotic materials with programmable mechanical properties

  NSF · $1.8M · 2019–2024

• EFRI NewLAW: Topological Mechanical Metamaterials Science

  NSF · $2.0M · 2017–2023

Frequent coauthors

• Vincent Tournat

  Le Mans Université

  69 shared

• Bolei Deng

  Massachusetts Institute of Technology

  40 shared

• Pai Wang

  36 shared

• Johannes T. B. Overvelde

  Institute for Atomic and Molecular Physics

  35 shared

• James C. Weaver

  31 shared

• Antonio Elia Forte

  King's College London

  31 shared

• Sung Hoon Kang

  Johns Hopkins University

  25 shared

• Ahmad Rafsanjani

  University of Southern Denmark

  24 shared

Labs

• Bertoldi GroupPI