News

Dr. Francesco Vicentini
Post-Doctoral Fellow
Aerospace Engineering and Engineering Mechanics
The University of Texas at Austin

April 14, 2026

Variational phase-field models for brittle fracture are powerful computational tools for studying Griffith-type crack propagation under complex three-dimensional and multiaxial loading scenarios. However, they struggle to accurately capture fracture nucleation, i.e., the onset of cracks in quasi-brittle materials. While effective for tensile-driven fractures (mode I), they fail under multiaxial loading due to the lack of flexibility in prescribing a material-specific strength surface.
Traditional energy decomposition approaches often lead to questionable residual stresses, prompting non-variational modifications that sacrifice the physical, mathematical, and numerical advantages of an energy minimization framework.
This limitation stems from the fact that classical phase-field models merely regularize the sharp Griffith fracture model, which lacks a nucleation concept, unlike sharp cohesive
fracture models.
To overcome this, we propose a variational phase-field model that approximates cohesive fracture allowing the inclusion of an arbitrary strength surface as a material property. Additionally, similar to what was observed in gradient damage models coupled with plasticity, we demonstrate that this formulation enables sharp cohesive fractures, providing an approximation that avoids smearing of the displacement field. The model naturally incorporates a sharp non-interpenetration condition, thus eliminating the need for additional energy decompositions.

Bio: Francesco Vicentini recently completed his PhD in September 2025 at ETH Zurich under the supervision of Prof. Laura De Lorenzis, with a thesis on phase-field modeling of brittle and cohesive fracture. His doctoral research focused on fracture nucleation and fracture in heterogeneous materials from a theoretical and numerical perspective. He is currently a postdoctoral researcher in the laboratory of Prof. Ravi-Chandar at The University of Texas at Austin, with a fellowship granted by the Swiss National Science Foundation.

Contact: Krishnaswamy Ravi-Chandar (ravi@utexas.edu)

Dr. Jong-Eun (Jaden) Suh
Senior Post-Doctoral Scholar
Space Structures Laboratory
California Institute of Technology

April 16, 2026

The traditional approach to building large space structures, based on deployable structural concepts, has enabled structures at scales of several tens of meters. However, achieving lightweight yet stiff designs, ensuring reliable deployment, and overcoming launch vehicle constraints remain significant challenges for realizing high-precision space structures at much larger scales. This talk begins by presenting novel structural concepts based on origami-inspired designs, which enable both high load-bearing capacity and reconfigurability for future adaptive space systems. It then introduces recent efforts toward developing new in-space assembly architectures that enable the construction of large space structures beyond the limitations of deployable systems. The presentation concludes by highlighting key research directions required to enable next-generation large-scale, high-precision space structures.

Contact: Noel Clemens (clemens@mail.utexas.edu)

Dr. Zhigang Suo
Professor
Harvard University

April 20, 2026

The aspiration to develop polymers for sustainability, as well as functions, instigates advances in polymer science. This seminar draws upon recent experience in my group. We discover that a polymer network in which entanglements greatly outnumber crosslinks simultaneously achieves high modulus and high fatigue threshold. As a second example, a composite of multiple species of polymers separates into phases, but the coarsening of the phases can be arrested, leading to stable nanocomposites of high crack resistance. These examples illustrate how chemistry and topology determine mechanical properties of polymers.

Bio: Zhigang Suo is the Allen E. and Marilyn M. Puckett Professor of Mechanics and Materials at Harvard University. He earned a bachelor degree at Xian Jiaotong University in 1985, and a PhD at Harvard University in 1989. Suo joined the faculty of the University of California at Santa Barbara in 1989, Princeton University in 1997, and Harvard University in 2003. His research centers on the mechanical behavior of materials. Suo is a member of NAE and NAS, elected for his seminal contributions to many areas, including fracture, deformation, polarization, and diffusion, with applications for microelectronics, large-area electronics, soft materials, active materials, and lithium-ion batteries.

Contact: Rui Huang (ruihuang@mail.utexas.edu)

Dr. Julian Rimoli
Professor and Chair
Mechanical and Aerospace Engineering
University of California, Irvine

April 21, 2026

The term tensegrity, derived from tensional integrity, refers to a class of structural systems composed of bars and strings that achieve mechanical stability through pre-stressing of their string members. Conventional models of these structures assume rigid bars, linear elastic cables, and treat the Euler buckling load of any bar as a failure threshold. In practice, these assumptions break down under dynamic loading. In the first part of this talk, we introduce a physics-based reduced-order model for studying the dynamic and nonlinear response of tensegrity-based planetary landers. Using this model, we demonstrate that buckling of individual members does not necessarily imply structural failure; on the contrary, post-buckling behavior acts as a load-limiting mechanism that distributes forces evenly throughout the structure, dramatically increasing the amount of energy that can be stored elastically. This finding reframes post-buckling as a design opportunity rather than a failure mode. In the second part, we show how these insights translate into the design of novel metamaterials. We introduce the first realizable three-dimensional tensegrity lattice and demonstrate that it exhibits a previously unobserved mechanical behavior: severe deformation without strain localization. Unlike conventional materials, which fail through localized deformation bands, these lattices distribute deformation broadly throughout their architecture, enabling exceptional energy absorption and failure resistance. In the third and final part, we address the fundamental question of why delocalization occurs. Using graph theory, we represent each lattice as a pair of coupled networks—one carrying tension, the other compression—and show that delocalization arises from an intrinsic asymmetry in their connectivity: when the tension network remains more connected than the compression network, deformation spreads throughout the structure instead of localizing. This framework, recently published in Nature Metamaterials, provides the first mechanistic and predictive foundation for designing architected structures that intrinsically resist failure localization.

Bio: Julián J. Rimoli is the Department Chair and Dean’s Professor of Mechanical and Aerospace Engineering at the University of California, Irvine. He obtained his Engineering Diploma in Aeronautics from Universidad Nacional de La Plata, Argentina, in 2001, and received his M.Sc. and Ph.D. in Aeronautics from Caltech in 2005 and 2009, respectively. Following a postdoctoral appointment at the Department of Aeronautics and Astronautics at MIT, he joined Georgia Tech in 2011, where he held the Pratt & Whitney Professorship in Aerospace Engineering until moving to UC Irvine in 2022. His research lies at the intersection of computational mechanics, architected materials, and aerospace structures. He is a Fellow of ASME and an Associate Fellow of AIAA, and was selected for the National Academy of Engineering’s U.S. Frontiers of Engineering Symposium. He is the recipient of the NSF CAREER Award, the Ernest E. Sechler Memorial Award in Aeronautics, and the James Clerk Maxwell Young Writers Prize.

Contact: John-Paul Clarke (johnpaul@utexas.edu)

Thursday September 1, 2022
Time: 3:30 – 4:30pm

This seminar will be held in-person in ASE 1.126

Gabriel Sanoja Lopez, Assistant Professor
Department Research Areas: Advanced Materials, Polymers and Nanotechnology

Molecular Insights into the Mechanical Lifetime of Elastomers

Elastomers are ubiquitous in applications that require large reversible deformations. Although toughness remains an important design consideration to prevent catastrophic failure at high loads, lifetime is often controlled by the progressive growth of an inherent flaw over time. This fracture by mechanical fatigue remains poorly understood due to the inability to visualize and quantify damage by network chain scission and understand fracture mechanisms under a range of loads.

In this seminar, I will discuss how tagging model elastomers with probes that fluoresce upon chain elongation until failure enables mapping and quantification of molecular damage in elastomers. I will consider fracture under two common loads – (i) cyclic loading over numerous cycles of low load (i.e., cyclic fatigue) and (ii) rapid decompression from supersaturated pressures (i.e., cavitation) to outline design rules for fatigue- and cavitation-resistant elastomers based on fracture mechanisms.

For further information, please contact Dr. Stelios Kyriakides at skk@mail.utexas.edu or (512) 471-4167

Listen to a podcast HERE where Professor Liechti is interviewed by Harry Dankowicz, Editor of Applied Mechanics Reviews.

The 2016 Congress of the International Union of Theoretical and Applied Mechanics (IUTAM) was held in Montreal, Canada on August 21-26. This is a main event in mechanics held every fours years; this year the Congress was attended by approximately 2100 researchers. As is the custom, the presiding Bureau selected 3 young scientists for the Bureau Prize, based on their papers and their presentations at the Congress. To be eligible for the award, a presenter must be no older than 35 years of age at the time of the Congress, and must indicate that he/she wishes to be considered for the award. The recipient in solid mechanics was Dr. Stavros Gaitanaros, Ph.D. Engineering Mechanics, The University of Texas at Austin, 2014, presently assistant professor in civil engineering at Johns Hopkins University. The title of his paper and presentation was: “The effect of Polydispersity on the Crushing of Open-Cell Random Foams,” by Stavros Gaitanaros, Stelios Kyriakides, Andrew M. Kraynik.

Professor Stelios Kyriakides of the Department of Aerospace Engineering and Engineering Mechanics at The University of Texas at Austin has been selected by the Cockrell School of Engineering to receive the 2016 Joe J. King Professional Engineering Achievement Award. The award, funded by Cockrell School alumnus Joe J. King, ME 1925, recognizes a faculty member who has made significant contributions in furthering the profession of engineering. Mr. King’s education in engineering, his years of practice as an engineer and the rewards he received in his practice left him with an increasingly deep respect for the profession. This respect, along with his love for his alma mater, led him to establish the award.

Professor Krishnaswamy Ravi-Chandar has been selected to receive the 2015 Daniel C. Drucker Medal, one of the ASME society awards for achievement. Instituted by the Applied Mechanics Division of ASME, the Drucker medal is conferred in recognition of distinguished contributions to the field of applied mechanics and mechanical engineering through research, teaching and service to the community over a substantial period of time. Congratulations!

Professor Kenneth M. Liechti has been selected to receive the 2015 Award for Excellence in the Adhesion Society. The Adhesion Society’s Award for Excellence, sponsored by 3M, is the Society’s premier award for outstanding achievements in scientific research relating to adhesion. Congratulations!