Seminars

Seminars are held Wednesdays, at 3:30 pm, in person, at Zumberg Hall of Science, Room 252 (ZHS 252) and/or as Zoom webinars. See the individual seminar announcements for details.

Archive of Seminar Announcements:

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Keynote Lecture Series Archive

Spring, 2026

Printability and Deformation Mechanics of Additively Manufactured Metals

Yinmin (Morris) Wang

Professor
Department of Materials Science and Engineering
University of California, Los Angeles
Los Angeles, CA

Additive manufacturing (AM) has attracted increasing attention due to its ability to produce complex geometric components with superior materials properties in a single print. One big challenge is, however, that many structural materials are difficult to print due to the extreme processing conditions associated with AM. Laser powder-bed-fusion (L-PBF), for example, involves processes that have ultrafast cooling rates and large temperature gradients, which trigger microcracks in many high-strength materials. This talk will present my group recent efforts to investigate the printability of pure tungsten – one of the most challenging materials for AM due to its high melting point (3422°C) and high ductile-to-brittle transition temperature (DBTT). We will discuss, step-by-step, how the printability issue can be systemically tackled. The second part of my talk will focus on another “tough-to-print” material: the high-strength, lightweight Al7075 alloy, widely used in aerospace and automotive industries. We demonstrate that extraordinary mechanical properties – including record specific ultimate tensile strength and high ductility – can be achieved via a nanoparticle inoculation strategy. In situ synchrotron X-ray diffraction was applied to reveal the unique deformation mechanics of these alloys, specifically the complex interactions introduce additional strengthening mechanisms to the material system. Based on these observations, we will briefly discuss alloy design strategies for high performance structural materials in future applications.

Yinmin Morris Wang, Professor of Materials Science and Engineering at UCLA. Yinmin (Morris) Wang is a professor of Materials Science and Engineering at the University of California, Los Angeles (UCLA). He joined UCLA as a full professor in 2020 after spending 17 years at Lawrence Livermore National Laboratory (LLNL). At LLNL, he was the inaugural recipient of the Harold Graboske Fellowship, after obtaining his Ph.D. from Johns Hopkins University. His research group focuses on the structure-property relationships of additively manufactured metals, the mechanics of nanostructured materials, and lithium-ion batteries. Prof. Wang was elected as a Fellow of the American Physical Society and has received several prestigious honors, including Nano50 Innovator Award and multiple Director’s Science & Technology Awards at LLNL. He also served as an Editorial Board Member of Scientific Reports from 2017 to 2020.

Wednesday, January 14, 2026

3:30 PM

Zumberg Hall of Science, Room 252 (ZHS 252)

host: Chen

Improving Engineering Resilience and Sustainability through Engineered Living Materials

Qiming Wang

Associate Professor
Sonny Astani Department of Civil and Environmental Engineering
University of Southern California
Los Angeles, CA

Modern society demands engineering materials with high resilience and sustainability, yet most conventional materials degrade under environmental hazards or pose long-term environmental risks. Urban infrastructure materials age and fail, while widely used plastics suffer from extremely low biodegradability. In contrast, biological living materials exhibit extraordinary resilience and sustainability through living cells that enable self-growing, self-remodeling, self-healing, and self-strengthening. In this talk, we present a strategy that integrates living components—such as microorganisms, plants, and chloroplasts—into traditional engineering materials to create engineered living materials. These materials behave more like biological systems, responding dynamically to environmental conditions. For example, bacteria-assisted 3D-printed polymers can self-grow into highly tough, shell-like structural composites, while chloroplast-assisted polymers can harness carbon dioxide for photosynthetic self-strengthening. This approach opens new pathways for sustainable, adaptive, and high-performance materials.

Qiming Wang, Associate Professor at USC. Qiming Wang is an Associate Professor and Stephen Schrank Early Career Chair in the Sonny Astani Department of Civil and Environmental Engineering at the University of Southern California (USC). He was previously a postdoctoral associate in Mechanical Engineering at the Massachusetts Institute of Technology and earned his Ph.D. in Mechanical Engineering from Duke University in 2014. He has received numerous honors, including the NSF CAREER Award, ONR and AFOSR Young Investigator Awards, the Engineering Mechanics Institute Leonardo Da Vinci Award, and the Society of Manufacturing Engineers Outstanding Young Manufacturing Engineer Award. His research focuses on the manufacturing and mechanics of advanced materials and structures to address challenges in infrastructure, energy, environment, robotics, and healthcare. A major thrust of his work is the development of engineered living materials by integrating living components—such as microorganisms, plants, and living chemistry—into engineering materials using modern manufacturing technologies. His research has been widely featured in major media outlets, including Science, Nature, The Washington Post, NBC News, and The Wall Street Journal.

Wednesday, January 21, 2026

3:30 PM

Zumberg Hall of Science, Room 252 (ZHS 252)

host: Maghsoodi

The Separation Aerodynamics of Idealized Fragmenting Meteoroids

Stuart Laurence

Professor
Department of Aerospace Engineering
University of Maryland
College Park, MD

For a meteoroid undergoing break-up within the atmosphere, the high-speed aerodynamic interactions between fragments immediately following disruption play a critical role in determining the risks posed at the terrestrial surface. In this seminar, I will first describe experimental, computational, and theoretical studies of the interactions between two isolated bodies as a basis for understanding the more general separation problem, highlighting the importance of “shock surfing”, where one body rides the shock of the other body downstream. I will then describe recent experiments in a hypersonic wind tunnel to determine the separation characteristics of an idealized fragmented meteoroid, consisting of an initially spherical cluster of up to 115 close-packed spherical bodies. For equal-sized fragments, the mean separation velocity follows a power law as a function of population with an exponent of ~0.4, while individual velocities are well-modeled by a single-parameter Rayleigh distribution. In unequal clusters, mass retention in sub-clusters decreases the mean separation velocity, but individual velocities again follow approximate Rayleigh distributions (with the governing parameter now radius-dependent). An examination of the most ejected bodies in the dataset also reveals that shock surfing can produce significant outliers and potentially explain a substantial portion of the discrepancy between airburst observations and previous predictions.

Stuart Laurence, Professor at University of Maryland. Stuart Laurence is a Professor of Aerospace Engineering at the University of Maryland, College Park. He completed his undergraduate education at the University of Auckland, New Zealand, in 2001 and then received his M.S. and Ph.D. in Aeronautics from the California Institute of Technology in 2002 and 2006. After working as a scientific researcher at the German Aerospace Center (DLR) in Göttingen, he moved to the University of Maryland in 2013. His research interests encompass various aspects of high-speed flows, including boundary-layer transition and turbulence, shock-wave/boundary-layer interactions, multi-body interactions, fluid-structure interactions, and multi-phase flows. He is a recipient of the NSF CAREER Award and the DARPA Young Faculty Award, an Associate Fellow of the AIAA, and an Associate Editor of Experiments in Fluids.

Wednesday, January 28, 2026

3:30 PM

Zumberg Hall of Science, Room 252 (ZHS 252)

host: Pantano

Hierarchical Learning and Control for Agile and Adaptive Legged Robots

Quan Nguyen

Assistant Professor
Aerospace & Mechanical Engineering Department
University of Southern California
Los Angeles, CA

Optimization-based control methods, such as model predictive control (MPC) and trajectory optimization, are essential to advancing the locomotion capabilities of legged robots. However, for successful deployment in real-world environments, legged robots must be capable of rapid adaptation to unknown terrain, robust handling of model uncertainties, and effective interaction with unknown objects to perform practical manipulation tasks.

In this talk, I will present a hierarchical model predictive control framework that enables legged and humanoid robots to perform dynamic loco-manipulation tasks. I will also highlight our recent work on adaptive force-based control that enables legged robots to handle significant model uncertainty. These strategies allow the robots to interact robustly with unknown objects, particularly in scenarios involving the transport of heavy loads over rough terrain.

Finally, I will discuss how we extend our hierarchical control principles into the domain of reinforcement learning to acquire long-term adaptive behaviors in both control actions and trajectory planning for legged and humanoid robots.

Quan Nguyen, Asst. Professor in Aerospace & Mechanical Engineering. Quan Nguyen is an Assistant Professor of Aerospace and Mechanical Engineering at the University of Southern California. He is also the Chief Scientific Officer of VinMotion, a humanoid robotics company established by Vingroup, the largest private enterprise in Vietnam. Prior to joining USC, he was a Postdoctoral Associate in the Biomimetic Robotics Lab at the Massachusetts Institute of Technology (MIT). He received his Ph.D. from Carnegie Mellon University (CMU) in 2017 with the Best Dissertation Award.

His research interests span different learning and control approaches for highly dynamic robotics, including nonlinear control, trajectory optimization, adaptive control, and reinforcement learning. His work was featured widely in many major media channels, including CNN, BBC, NBC, IEEE Spectrum, etc. Nguyen won the Best Presentation of the Session at the 2016 American Control Conference (ACC) and the Best System Paper Finalist at the 2017 Robotics: Science & Systems conference (RSS). He is also a recipient of the 2020 Charles Lee Powell Foundation Faculty Research Award.

Wednesday, September 10, 2025

3:30 PM

Seaver Science Library, Room 202 (SSL 202)

host: Ronney

Soft Elastic Composites: Microstructure evolution, macroscopic multi-physics response, instabilities and associated soft modes

Pedro Ponte Castañeda

Professor
Department of Mechanical Engineering and Applied Mechanics
Graduate Group in Applied Mathematics and Computational Sciences
University of Pennsylvania
Philadelphia, PA

Soft elastic composite materials can undergo large deformations under normal operating conditions and, in many applications, such as in robotics and prosthetics applications, they are designed with the objective of undergoing controlled deformation by means of externally applied magnetic, electrical, pneumatic or other types of fields. They include porous, particle- and fiber-reinforced rubbers, thermoplastic and magnetorheological elastomers, dielectric elastomer composites, polymer foams, muscle and other biological tissues. As a consequence of the finite deformations involved, their microstructure evolves with the deformation and their constitutive or rheological behavior can be highly nonlinear and strongly anisotropic. This presents a challenge for the application of homogenization methods, which were originally developed to characterize the effective material parameters of composites, such as, for example, the thermal conductivity of a two-phase composite material, or the Young’s modulus of an isotropic metal polycrystal. In this presentation, I will give an overview of several methods that have been recently developed to characterize the multi-physics constitutive response of soft composites, as well as the evolution of the microstructure and the possible development of instabilities in such material systems. In addition, I will present some explicit examples, including those leading to a certain type of ‘twining’ instabilities and associated soft modes of deformation.

Pedro Ponte-Castañeda, professor at the University of Pennsylvania. Pedro Ponte Castañeda is Raymond S. Markowitz Faculty Fellow and Professor in Mechanical Engineering & Applied Mechanics, Applied Mathematics & Computational Science, and Mathematics (secondary) at the University of Pennsylvania. He earned a B.S. in Mechanical Engineering and a B.A. in Mathematics from Lehigh University, and a Ph.D. in Applied Mathematics from Harvard University. He was Assistant Professor of Mechanical Engineering at the Johns Hopkins University (1987-90) and Professor of Mechanics at the École Polytechnique (2004-08). He has held visiting positions at the C.N.R.S. (France), Cambridge University, IMDEA Materials (Spain) and the University of Stuttgart. His honors include the Humboldt Senior Research Award (2013) and the ASME Warner T. Koiter Medal (2016).