Seminars

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 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 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 Role of Left Ventricular–Arterial Interactions on Coronary Fluid Dynamics

Soha Niroumandi

Ph.D. Candidate
Aerospace & Mechanical Engineering Department
University of Southern California
Los Angeles, CA

Coronary blood flow is governed by a complex interplay between heart contraction, arterial pulsatility, and wave dynamics, making it highly sensitive to ventricular–arterial hemodynamic coupling. Consequently, coronary perfusion is strongly influenced by pressure and flow wave reflections within both the aorta and the coronary arterial network.

In this talk, I will examine the role of left ventricular–arterial interactions in shaping coronary hemodynamics, providing mechanistic insights from a one-dimensional model of the entire circulatory system. The model integrates reduced-order one-dimensional Navier–Stokes hemodynamics formulations (coupled to hyperelastic tube laws) that govern the corresponding fluid–structure dynamics in each vascular segment coupled with ODE-based representations of the heart and microvasculature, solved using the pseudo-spectral Fourier continuation approach.

Soha Niroumandi is a Ph.D. candidate in the Department of Aerospace and Mechanical Engineering at the University of Southern California (USC). She is advised by Professor Niema Pahlevan. Soha received her MSc in aerospace and mechanical engineering from the University of Tehran. Her research focuses on the intersection of mechanics, AI, and cardiovascular health, with an emphasis on non-invasive methods for early disease risk detection. Her research has been recognized with an American Heart Association Predoctoral Fellowship and selection as a 2025 MIT Rising Star in Mechanical Engineering.

Wednesday, February 4, 2026

3:30 PM

Zumberge Hall of Science, Room 252 (ZHS 252)

 

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Laboratory Experiments on Internal Solitary Waves

Jen-Ping Chu

Ph.D. Candidate
Aerospace & Mechanical Engineering Department
University of Southern California
Los Angeles, CA

Internal solitary waves (ISWs) are ubiquitous in stratified water and play a crucial role in the transport of energy and nutrients in the ocean. This seminar introduces a novel jet-array wavemaker (JAW) that generates ISWs through a prescribed mass flux, offering a flexible alternative to traditional gate-release experimental methods. Using synchronized planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV), we demonstrate that the JAW system produces small-to-intermediate amplitude waves that closely match theoretical predictions. Larger waves approaching theoretical limits reveal interfacial mixing and Kelvin-Helmholtz instabilities. Additional experiments and complementary RANS simulations characterize the impact of floating structures or vegetation canopies (e.g., kelp farms) on ISW dynamics. Our findings indicate that high-porosity canopies result in minor amplitude reduction. Dense canopies trigger significant wave transformation. In dense canopy cases, the shear layer developing at the bottom edge of the canopy reaches strengths comparable to the inherent shear of an ISW at the pycnocline, generating vortex pairs that accelerate upper-layer fluid. This interaction leads to complex nonlinear amplitude modulation and significant energy redistribution.

Jen-Ping Chu is a Ph.D. candidate in the Department of Aerospace and Mechanical Engineering at the University of Southern California (USC). He is co-advised by Professor Mitul Luhar in Aerospace and Mechanical Engineering and Professor Patrick Lynett in the Department of Civil and Environmental Engineering. Jen-Ping earned his Bachelor’s degree in Mechanical Engineering from National Taiwan University and received his Master’s in Aerospace Engineering from USC during his doctoral studies.

His research utilizes a combination of flow visualization and RANS modeling to study wave-structure interactions. His early doctoral work focused on internal solitary waves in stratified conditions, he is currently examining free-surface solitary wave impacts on waterfront structures as part of a Naval project.

Wednesday, February 4, 2026

3:30 PM

Zumberge Hall of Science, Room 252 (ZHS 252)

 

host: Ronney

 

host: Ronney

 

host: Egolfopoulos

 

host: Zhao/Maghsoodi

 

host: Domaradzki

 

host: Maghsoodi

 

host: Zhao

 

host: Xu

 

host: Zhao

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 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).

Wednesday, November 5, 2025

3:30 PM

Seaver Science Library, Room 202 (SSL 202)

 

host: Plucinsky