Seminars

Flow Control À la Mode

Maziar Hemati

Assistant Professor
Department of Aerospace Engineering and Mechanics
Unversity of Minnesota, Twin Cities
Minneapolis, MN

Biological flyers and swimmers have a great capacity for interacting with their fluid environments. This ability is demonstrated through the agility, efficiency, and environmental awareness exhibited by numerous creatures, including birds, fish, and insects. While human-engineered systems have benefited from biological inspiration, the performance gains realized have often fallen short of their full potential. A primary limitation to attaining further improvement has been a scarcity of reliable low-dimensional fluid dynamics models, which are often needed (1) to determine the state of a complex flow from available on-board sensors (i.e., flow sensing), and (2) to exploit that knowledge to determine and execute a best course of action for achieving a desired objective (i.e., feedback control). In this talk, we will consider modal decomposition strategies aimed at obtaining low-dimensional dynamical systems models from empirical data. In particular, we will present recent advances in techniques tailored to extract descriptive insights and predictive models from large, streaming, and noisy datasets. The second half of the talk will present a dynamic mode shaping perspective for feedback flow control synthesis. The perspective will be used to highlight a fundamental performance limitation inherent to standard observer-based control structures, suggesting that flow reconstruction from sensor measurements may be inadvisable in some flow control applications.

Maziar Hemati is an Assistant Professor in the Department of Aerospace Engineering and Mechanics at the University of Minnesota, Twin Cities. Dr. Hemati’s research program is aimed at gaining an improved understanding of the various mechanisms required to achieve reliable fluid flow sensing and control in the context of human-engineered systems, including flight vehicles, robotic swimmers, and wind turbine arrays. He is a recipient of the 2019 AFOSR Young Investigator Award. Prior to joining the faculty at the University of Minnesota, he served as a Post-Doctoral Research Associate in the Department of Mechanical and Aerospace Engineering at Princeton University. He earned his Ph.D. and M.S. in Mechanical Engineering and his B.S. in Aerospace Engineering, all from UCLA.

Wednesday, January 16, 2019
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Spedding

Active and Architectured Structures: From Nematic Elastomers Sheets to
Rigidly-Foldable Origami.

Paul Plucinsky

Postdoctoral Researcher
Department of Aerospace Engineering and Mechanics
College of Science & Engineering
Unversity of Minnesota, Twin Cities
Minneapolis, MN

Thin and slender structures exhibit a broad range of mechanical responses as the competition between stretching and bending in these structures can result in buckling, localized deformations like folding, and tension wrinkling. Active and architectured materials also exhibit a broad range of mechanical responses as features that manifest at the micro and mesoscale in these materials result in mechanical couplings at the engineering scale (thermal/electrical/dissipative/…) and novel function (e.g., the shape memory effect, piezoelectricity in select metal alloys, the immense fracture toughness of Nacre and like materials, …). Given this richness in behaviors, my research broadly aims to address the following questions: What happens when active and architectured materials are incorporated into a thin and slender structures? Do phenomena inherent to these materials compete with or enhance those inherent to these structures? Does this interplay result in entirely new and unexpected phenomena? And can all this be exploited to design new functionality in engineering systems?

In this talk, I will explore these questions in the context of thin sheets of an active material in nematic elastomer as well as architectured sheets designed to fold continuously as origami. For the latter, I will completely characterize all rigidly and flat-foldable origami, and describe an effcient algorithm to compute their designs and deformations. For the former, I will show that a material instability inherent to nematic elastomers at the micron scale is capable of suppressing a structural instability (wrinkling) at the engineering scale. These results provide novel, yet concrete, design guidance for improving the effciency solar sails and the performance of other membrane structures (where wrinkling can be an impediment to their functionality), as well as tools to effciently investigate robust and elegant concepts for deployable space structures, reconfigurable antennas, and soft robotics using origami.

Maziar Hemati is a postdoctoral researcher studying the mechanics of Origami, helical structures and shape memory alloys at the University of Minnesota. He attended University of Michigan, receiving a Bachelors of Science in Civil Engineering (2010) and and Masters of Science in Structural Engineering (2011). He then moved to Caltech, where he received a Ph.D in Mechanical Engineering (2017) studying the deformations of thin nematic elastomer sheets. When not folding paper—and when his Achilles is functioning properly—you can often find him on the basketball court.

Wednesday, January 23, 2019
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Oberai

Planning and Decision-Making for Energy Efficient and Sustainable Autonomous Systems

Ran Dai

Netjets Assistant Professor
Mechanical and Aerospace Engineering Department
The Ohio State University
Columbus, OH

Many autonomous systems will benefit from prolonged operational time and reduced power consumption in a variety of long-duration missions, ranging from terrestrial operating domain to interplanetary space exploration. Due to limited power capacity, dynamic operating environments, complex system behaviors, and strict mission constraints, it is challenging to realize full autonomy with capabilities of sustained power supply and energy efficient operations. Without human intervention, real-time planning and decision-making, including both motion planning and logic/reasoning decisions, play a critical role in assuring the reliability and performance of such systems toward accomplishing the mission objectives.

This talk will present our work on developing vision-based energy awareness, sophisticated modeling approach, highly implementable optimization algorithms, and machine learning based auto-tuning method that collectively contribute to advanced planning and decision-making strategies for energy efficient and sustainable autonomous systems. Applications in two types of autonomous systems will be discussed. One is solar-powered ground robot that harvests energy from the environment and charges the storage batteries as backup to extend the endurance time or realize persistent operations. The other type of application focuses on space vehicles in complex missions involving multiphase or hybrid operations where onboard propellant is limited and timely ground support is unavailable. The overall objective of real-time planning and decision-making for both types of autonomous systems is to realize high-level autonomy in energy harvesting and utilization under dynamic environments, complex operations, and mission constraints. Results obtained in virtual simulations are verified in real-world environments or experimental platforms that mimic the mission challenges, leading to a synthesized theoretical and experimental framework for evaluating improved performance of this transformational technique.

Ran Dai is a Netjets Assistant Professor in Mechanical and Aerospace Engineering Department at The Ohio State University. She received her B.S. degree in Automation Science from Beihang University and her M.S. and Ph.D. degrees in Aerospace Engineering from Auburn University. After graduation, she worked as an engineer in an automotive technology company, Dynamic Research, Inc., and conducted research and consulting in the areas of semi-autonomous vehicle guidance and control. From 2010 to 2012, Dr. Dai joined the Robotics, Aerospace, and Information Networks Lab at University of Washington as a postdoctoral fellow, where she involved in an energy management project with application to the next generation of Boeing 787 aircraft power systems. Dr. Dai’s research focuses on control and optimization of autonomous systems, motion planning and estimation of space vehicles, and networked dynamical systems. She is a recipient of the National Science Foundation Career Award and NASA Early Faculty Career Award.

Wednesday, February 6, 2019
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Flashner

Extremely Agile and Robust Legged Robots

Quan Nguyen

Postdoctoral Associate
Biomimetic Robotics Lab
Massachusetts Institute of Technology
Cambridge, MA

The mobility of man-made machines is still limited to relatively flat grounds, whereas humans and animals can traverse almost all surfaces of the earth including rocky cliffs or collapsed buildings.

In this talk, I will pose the question “How can we make robots with similar morphologies achieve such extremely agile and robust behaviors?” Enabling robots to exhibit such behaviors will one day facilitate robotic space exploration, disaster response, construction, etc. Furthermore, such time and safety critical missions also require robots to operate swiftly and stably while dealing with high levels of uncertainty and large external disturbances.

To achieve these capabilities, a unified adaptive control framework will be presented, that enables the ability to enforce stability and safety-critical constraints arising from robotic motion tasks under a high level of model uncertainty. Next, I will present novel optimization-based approaches to address the challenge of dynamic robotic walking over randomly generated stepping stones, and optimized jumping on high platforms. I will then show how these can be translated to real-world experiments, that enables (a) ATRIAS, a bipedal robot at CMU, to walk dynamically on stepping stones, and (b) MIT’s Cheetah 3 robot to jump up onto and jump down from a desk.

Quan Nguyen is a postdoctoral associate at the Biomimetic Robotics Lab, Massachusetts Institute of Technology (MIT). Prior to this, he completed his Ph.D. from Carnegie Mellon University (CMU) in 3.5 years with the Best Dissertation Award. His research interests span different control and optimization approaches for highly dynamic robotics including nonlinear control, trajectory optimization, real-time optimization-based control, robust and adaptive control. His work on the bipedal robot ATRIAS walking on stepping stones was featured on the IEEE Spectrum, TechCrunch, TechXplore and Digital Trends. His work on the MIT Cheetah 3 robot leaping on a desk was featured widely in many major media channels, including CNN, BBC, NBC, ABC, 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).

Wednesday, February 13, 2019
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Flashner

Manufacturability-Driven, Multi-Component Topology Optimization (MTO) for Top-Down Design of Structural Assemblies

Kazuhiro Saitou

Professor
Department of Mechanical Engineering
University of Michigan
Ann Arbor, MI

This talk presents a manufacturability-driven, multi-component topology optimization (MTO) framework for simultaneous design and partitioning of structures assembled of multiple components. Constraints on component geometry imposed by chosen manufacturing processes are incorporated in the conventional density-based topology optimization, with additional design variables specifying fractional component membership which enables continuous relaxation of otherwise discrete partitioning problems. The geometric constraints imposed by various manufacturing processes, such as size, perimeter length, undercut, and enclosed cavities, are also relaxed to enable the manufacturability evaluation of “gray” geometries that occur during the density-based topology optimization. Examples on minimum compliance structural assembly design for sheet metal stamping (MTO-S), die casting (MTO-D), additive manufacturing (MTO-A), and tailored-fiber composite process (MTO-C) show promising advantages over the conventional monolithic topology optimization. In particular, manufacturing constraints previously applied to monolithic topology optimization gain new interpretations when applied to multi-component assemblies, which can unlock richer design space for topology exploration. The talk will conclude with a brief overview of the latest developments on the MTO framework for continuous fiber printing processes and for “4D” printing processes.

Kazuhiro Saitou is Professor of Mechanical Engineering at the University of Michigan, Ann Arbor. He received BEng degree from University of Tokyo, and MS and PhD degrees from the Massachusetts Institute of Technology (MIT), all in Mechanical Engineering. His research interest includes algorithmic and computational design synthesis and design for manufacture and assembly, with applications in mechanical, industrial, and biomedical systems. Prof. Saitou was the recipient of several awards including Kos-Ishii Toshiba Award from ASME Design for Manufacturing and the Life Cycle Technical Committee, Innovative Design Component Award from ARPA-E Lightweighting Technologies Enabling Comprehensive Automotive Redesign (LITECAR) Challenge, Design and Systems Division Achievement Award from Japan Society of Mechanical Engineers, CAREER Award from US National Science Foundation, and best paper awards at international conferences. He has served as an Associate Editor for ASME Journal of Computing and Information Science in Engineering (JCISE), ASME Journal of Mechanical Design (JMD), and IEEE Transactions on Automation Science and Engineering (T-ASE), and is currently serving as an Associate Editor for JCISE (again) and a Senior Editor for T-ASE. He was a past Chair of the ASME Design Automation Technical Committee (DAC) and the ASME Design for Manufacturing and the Life Cycle Technical Committee (DFMLC), and the Editor-In-Chief for Conference Editorial Board of IEEE Conference on Automation Science and Engineering. He is Fellow of ASME and IEEE.

Wednesday, February 20, 2019
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Gupta

Smart and Advanced Manufacturing Innovation – Are we living up to the potential?

Sudarsan Rachuri

Technology Manager
US Department of Energy

Smart manufacturing is an emerging field that combines physical and intelligence. It can mean different things to different people, but essentially it is about smartly extracting information from the manufacturing system to improve overall efficiency of networked enterprises. Smart manufacturing provides effective and secure human-system platforms for better decision making and improving the overall productivity and efficiency of manufacturing across the networked enterprise. The talk will also describe the future needs of smart manufacturing with respect to disruptive technologies, industry best practices, and, more importantly, workforce and skills development.

Sudarsan Rachuri is a Technology Manager in the Advanced Manufacturing Office, EERE, and DOE. He is the Federal Program Manager for the CESMII. Prior to joining DOE, he was the program manager at National Institute of Standards and Technology (NIST) and also a research professor at George Washington University and worked in the CAD/CAE/PLM software industry.

Dr. Rachuri is the Editor-in-Chief of ASTM Smart and Sustainable Manufacturing Systems journal (www.astm.org/ssms). Rachuri is the founding member and was the vice chair of the ASTM subcommittee on sustainable manufacturing (E60.13) and a member of ASTM Smart Manufacturing Advisory Committee. Rachuri is the founding member and the Chair of the standards committee on ASME V&V 50 Verification and Validation of Computational Modeling for Advanced Manufacturing. Dr. Rachuri was a member of many ISO and ASME standards committees.

Dr. Rachuri is a Fellow of ASME and AAAS (American Association for the Advancement of Science). Dr. Rachuri received the 2016 ASTM International President’s Leadership Award. Dr. Rachuri won first prize in the 2017 World Standards Day (WSD) Paper Competition, awarded by The Society for Standards Professionals. Dr. Sudarsan Rachuri was recently honored with the Excellence in Research Award by the American Society of Mechanical Engineers (ASME) Computers and Information in Engineering (CIE) Division.

Friday, March 1, 2019
2:00 PM
USC Viterbi Center for Advanced Manufacturing, Conference Room
2727 S Flower St, Los Angeles, CA 90007

Advanced Manufacturing Seminar Series

host: Gupta

Mechano-Chemical Phase Transformations: Computational Framework, Machine Learning Studies and Graph Theoretic Analysis

Krishna Garikipati

Professor of Mechanical Engineering, and Mathematics
and
Director, Michigan Institute for Computational Discovery & Engineering
Departments of Mechanical Engineering and Mathematics
University of Michigan
Ann Arbor, MI

Phase transformations in a wide range of materials—for energy, electronics, structural and other applications—are driven by mechanics in interaction with chemistry. We have developed a general theoretical and computational framework for large scale simulations of these mechano-chemical phenomena. I will begin by presenting our recent work in this sphere, while highlighting some of its more insightful results. In addition to being a platform for investigating mechanically driven phenomena in materials physics, this work is a foundation to explore the potential of recent advances in data-driven modeling. Of interest to us are machine learning advances that may enhance our approaches to solve computational materials physics problems. I will outline the first of several recent studies that we have launched in this spirit. Such combinations of classical high-performance scientific computing and modern data-driven modeling now allow us to access large numbers of states of physical systems. They also motivate the study of mathematical structures for representation, exploration and analysis of systems by using these collections of states. With this perspective, I will offer a view of graph theory that places it in nearly perfect correspondence with properties of stationary and dynamical systems. This has opened up new insights to our earlier, large-scale computational investigations of mechano-chemically phase transforming materials systems. This treatment has potential for eventual decision-making for physical systems that builds on high-fidelity computations.

Krishna Garikipati is a computational scientist whose work draws upon nonlinear physics, applied mathematics and numerical methods. A very recent interest of his is the development of methods for data-driven computational science. He has worked for quite a few years in mathematical biology, biophysics and materials physics. Some specific problems he has been thinking about recently are: (1) mathematical models of patterning and morphogenesis in developmental biology, (2) mathematical and physical modeling of tumor growth, and (3) mechano-chemically driven phenomena in materials, such as phase transformations and stress-influenced mass transport.

Wednesday, March 6, 2019
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Oberai

Microstructural Engineering Of Energy-Related Materials

Ananya Renuka Balakrishna

Postdoctoral Researcher
Department of Aerospace Engineering and Mechanics
College of Science & Engineering
University of Minnesota, Twin Cities
Minneapolis, MN

Future advances in aerospace engineering depend on developing materials with enhanced properties. For example, the next generation of electric aircrafts will need light-weight low-fatigue materials, high-performance sensing and actuation materials, and high-density energy storage materials. Material properties can be drastically enhanced by tuning the materials’ microstructural features. In my research, I develop and apply phase-field methods to investigate how microstructures form and evolve in materials, and how we can engineer these microstructures to enhance material properties. In this talk, I will present applications of phase-field modeling to two material systems: electro-mechanical (ferroelectrics) and chemo-mechanical (batteries) systems. First, I will show how microstructural engineering of ferroelectric materials generate actuation strains several times greater than piezoceramics in market. Second, I will show that not only the electrodes’ microstructures but also their crystallographic texture can be tailored to enhance battery materials’ mechanical strength. Overall, the phase-field models developed in my research provide a theoretical and computation framework to engineer next generation aerospace materials with enhanced properties and extended lifespans.

Ananya Balakrishna is a postdoctoral researcher at the University of Minnesota investigating microstructures in magnetic and light-interactive materials. She completed her PhD in Solid Mechanics and Materials Engineering at the University of Oxford, before pursuing postdoctoral research at MIT as a Lindemann Postdoctoral fellow. Broadly, her research focuses on developing mathematical models to investigate the links between material microstructures and properties in energy storage and functional materials. Her research on engineering ferroelectric microstructures has been recognized by the Falling Walls London Lab prize, and the British Federation for Women Graduates Award. She has also won other awards including the ASME Best student paper award, and the Felix scholarship for her graduate study.

Wednesday, March 20, 2019
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Oberai

Nonlinear Dynamics with Noise

Bala Balachandran

Minta Martin Professor
Department of Mechanical Engineering
University of Maryland
College Park, MD

Nonlinearity influenced dynamics occurs in a variety of mechanical and structural systems. For operations of many of these systems, noise is often viewed as being undesirable. However, the interplay between noise and nonlinearity in a system can result in significant response changes that can be beneficial to a system’s performance. In this spirit, the work carried out to further our understanding on the constructive use of noise in a nonlinear system to realize noise-enhanced responses, noise-enabled stabilization, and noise-assisted response steering will be discussed. Efforts undertaken with partial control will be discussed. Representative physical systems that will be considered include coupled oscillator arrays at the micro-scale and macro-scale, flexible rotor systems, and pendulum systems. The findings of these studies are expected to be relevant to a variety of different nonlinear, mechanical and structural systems. Some thoughts on future directions in the realm of applied nonlinear dynamics will be presented to close the talk.

Bala Balachandran received his B. Tech (Naval Architecture) from the Indian Institute of Technology, Madras, India, M.S. (Aerospace Engineering) from Virginia Tech, Blacksburg, VA and Ph.D. (Engineering Mechanics) from Virginia Tech. Currently, he is a Minta Martin Professor of Engineering at the University of Maryland, where he has been since 1993. His research interests include nonlinear phenomena, dynamics and vibrations, and control. The publications that he has authored/co-authored include over ninety journal publications, a Wiley textbook entitled “Applied Nonlinear Dynamics: Analytical, Computational, and Experimental Methods” (1995, 2006), a third edition of a textbook entitled “Vibrations” (2019) by Cambridge University Press, and a co-edited Springer book entitled “Delay Differential Equations: Recent Advances and New Directions” (2009). He holds four U.S. patents and one Japan patent, three related to fiber optic sensors and two related to atomic force microscopy. He is a Contributing Editor of the International Journal of Non-Linear Mechanics and the Editor of the ASME Journal of Computational and Nonlinear Dynamics. He is a Fellow of ASME and AIAA.

Wednesday, April 3, 2019
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Udwadia

The Blood Microenvironment in Thrombosis and Hemostasis: The Good, Bad and the Sticky

Owen McCarty

Professor & Chair
Department of Biomedical Engineering
Oregon Health & Science University
Portland OR

Hemostatic plug formation upon blood vessel breach is initiated by platelet recruitment, activation and aggregation in concert with thrombin generation and fibrin formation. However, a similar process can also lead to pathological processes including deep vein thrombosis, ischemic stroke, or myocardial infarction, among others. We have developed narrow mechanism-specific agents targeting the intrinsic pathway of coagulation and demonstrated that experimental thrombosis and platelet production in primates is interrupted by selective inhibition of activation of coagulation factor (F)XI by FXIIa. In this seminar, I will present new data on the role of the endothelium in inactivating FXI, as well as studies on whether inhibiting FXI is beneficial in a non-human primate model of sepsis. I will present our first data from our clinical trial on the safety of inhibition of FXI, and plans to test the efficacy of FXI inhibition in dialysis. The understanding of the mechanisms by which the intrinsic pathway of coagulation promotes thrombus formation may support the rationale for the development of selective, safe and effective antithrombotic strategies targeting FXI.

Owen McCarty, a native of Rochester, received his B.S. in Chemical Engineering from SUNY Buffalo, and a Ph.D. degree in Chemical Engineering from Johns Hopkins University, where his research focused on the identification and characterization of tumor cell receptors for blood platelets and leukocytes. He performed his postdoctoral research on platelet cell biology in the Pharmacology Department at the University of Oxford and University of Birmingham, UK in the group of Dr. Steve Watson. Dr. McCarty joined Oregon Health & Science University in 2005, where he holds an appointment as a Professor in the Departments of Biomedical Engineering and Cell, Developmental & Cancer Biology and the Division of Hematology & Medical Oncology in the OHSU School of Medicine. Dr. McCarty serves as the Chair of the Biomedical Engineering Department and a fellow of the American Heart Association.

Wednesday, April 10, 2019
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Newton