Abstract: As form follows function, so shape governs the properties of structural and material systems. Recent studies on adaptive structures have capitalized on these connections to realize unprecedented tunability of system properties and functionality by passive or active transformations of system configuration. This two-part presentation describes integrated theoretical and experimental research efforts that advance these principles to deliver large control over wave propagation properties of adaptive structural and material systems. In the first part, a method is presented that broadly enhances capabilities for acoustic transducer arrays to guide wave energy via harnessing foldable, origami-based tessellations. The foldable arrays enable orders of magnitude change in acoustic energy delivery to points near and far from the surface of the tessellation using shape transformations and without resorting to digital control, and may find future application for instance for medical ultrasound therapy devices transported and deployed in the human body. In the second part of the presentation, strategies to leverage cellular architecture within elastomeric material systems are described that give rise to unusually large elastic wave damping properties. Using this concept, shock energy into the elastomeric metamaterials is found to be dramatically dissipated by tuned pre-compression constraint, and dampened more effectively than the heavier solid elastomer material. This concept is prime for future applications of lightweight personal protective equipment and recoverable shock absorbers. All together, these results encourage ongoing study to probe relations between shape and properties in adaptive structural and material systems to capitalize on potentials for large wave propagation control.

Biographical Sketch: Ryan L. Harne is an Assistant Professor in the Department of Mechanical and Aerospace Engineering at The Ohio State University where he directs the Laboratory of Sound and Vibration Research. Dr. Harne received the Ph.D. degree in Mechanical Engineering at Virginia Tech in 2012. From 2012 to 2015, Dr. Harne was a Research Fellow at the University of Michigan. His research expertise falls in the areas of vibration, acoustics, mechanics, and nonlinear dynamics. The outcomes of his research efforts have included several patents pending, one book, over 40 journal publications, and over 40 conference proceedings, alongside numerous students mentored and guided through their academic programs. Dr. Harne is active in ASME, ASA, and SPIE, where he serves in several elected and appointed roles. Dr. Harne was awarded a 2017 Air Force Research Lab Summer Faculty Fellowship from the Air Force Office of Scientific Research, the 2017 ASME Best Paper Award in Structures and Structural Dynamics, the 2016 Haythornthwaite Young Investigator Award from ASME, and the 2011 ASA Royster Award. He currently serves as an Associate Editor for The Journal of the Acoustical Society of America, Proceedings of Meetings on Acoustics.

Abstract: Induced by proteins within the cell membrane or by differential growth, heating, or swelling, spontaneous curvatures can drastically affect the morphology of thin bodies and induce mechanical instabilities. In this talk, we aim to describe how the differential swelling of soft materials induces a spontaneous curvature that can dynamically shape materials. The dynamics of fluid movement within elastic networks, and the interplay between swelling and geometry play a crucial role in the morphology of growing tissues, the shrinkage of mud and moss, and the curling of cartilage, leaves, and pine cones. Small volumes of fluid that interact favorably with a material can induce a spontaneous curvature that causes large, dramatic, and geometrically nonlinear deformations and instabilities, yet, the interaction of spontaneous curvature and geometric frustration in curved shells remains still poorly understood. This talk will examine the geometric nonlinearities that occur as slender structures are exposed to a curvature-inducing stimulus – surfaces crease, fibers coalesce and curl apart, plates warp and twist, and shells buckle and snap. I will describe the intricate connection between materials and geometry, and present a straightforward means to permanently morph 2D sheets into 3D shapes. If we can engineer adaptive structures that programmatically morph on command we will enable opportunities for deployable structures, soft robotic arms, mechanical sensors, and rapid-prototyping of 3D elastomers.

Biographical Sketch: Douglas Holmes is an Assistant Professor in the Department of Mechanical Engineering at Boston University.  He received degrees in Chemistry from the University of New Hampshire (B.S. 2004), Polymer Science & Engineering from the University of Massachusetts, Amherst (M.S. 2005, Ph.D. 2009), and was a postdoctoral researcher in Mechanical & Aerospace Engineering at Princeton University. Prior to joining Boston University, he was an Assistant Professor of Engineering Science and Mechanics at Virginia Tech. His group’s research specializes on the mechanics of slender structures, with a focus on understanding and controlling shape change. He received the NSF CAREER Award and the ASEE Ferdinand P. Beer and E. Russell Johnston Jr. Outstanding New Mechanics Educator award.

Abstract: It has been remarked that “invention is the mother of necessity” – not the other way around. Technology breakthroughs of themselves, can and do create world markets. In a very short period of history, the gas turbine, youngest of major energy conversion devices, has changed and created global markets in aviation, in marine propulsion and in generation of electric power. In this talk we will discuss how in less than 80 years the gas turbine has come to dominate aircraft propulsion and now, global electrical power generation. In 1939, the first gas turbines had a thermal efficiency of about 18%. Over the years, many thousands of engineers and researchers in academia, government and industry have worked to raise turbine inlet temperatures, increase pressure ratios, enhance combustion, perfect new materials and improve designs, so that modern gas turbines now achieve 40-45% in simple cycle operation. In combined cycle operation, the gas turbine has become the thermal efficiency superstar of the electric power plant world, bringing about combined cycle thermal efficiencies exceeding 60%. Today, gas turbine technology and testing improvements continue apace, and some of these will be discussed. Fuel usage is being drastically reduced in newer land-based gas turbines through the first practical use of recuperators and intercoolers. Small gas turbines are now being used to produce electricity from greenhouse gases at municipal waste water treatment plants. A commercial closed cycle helium gas turbine has been proposed to generate electricity, using a pebble bed modular nuclear reactor as a heat source. The engine in production for the F-135 Joint Strike Fighter is pushing the limits of jet engine technology and will lead to future improvements in gas turbine technology.

Biographical Sketch: Lee Langston received a BSME (1959) from the University of Connecticut, and an MS (1960) and a Ph.D. (1964) from Stanford University. He was with Pratt and Whitney Aircraft as a research engineer working on fuel cells, heat pipes and jet engines from 1964 to 1977. During these years, he also participated in mountain climbing activities in various parts of the world. He joined the mechanical engineering faculty at the University of Connecticut in 1977, rising to the rank of Professor in 1983. At UConn, he has taught graduate and undergraduate courses in heat transfer and fluid mechanics, with research activities involving the measurement, understanding and prediction of secondary flows in gas turbines. He served as Interim Dean of the School of Engineering in 1997-98 and became Professor Emeritus in 2003. He is a Life Fellow of the American Society of Mechanical Engineering Engineers (ASME), has served as Editor, ASME Journal of Engineering for Gas Turbines and Power (2001-2006) and was a member of the Board of Directors of the ASME International Gas Turbine Institute (IGTI). In 2015, he was the recipient of IGTI’s R. Tom Sawyer Award, for outstanding contributions in the field of gas turbines. For the past seventeen years Professor Langston has written a column and a variety of articles on gas turbine technology for IGTI and ASME’s Mechanical Engineering Magazine.

Abstract: Early stages of human neural development include neural induction, shaping, folding, and closure of neural tubes. Current understanding of early neural development relies on animal studies. However, insights in human neural development mechanism are very limited, largely due to the inaccessibility of human embryo, lack of in vitro models, and ethical concerns. In this talk, I will first discuss our recent experimental and computational works using a series of microengineered tools to model the neural induction, polarization, and bending of neural tubes. Our results demonstrate that biomechanical cues, in addition to morphogen gradient, also play functional roles during multiple stages of neurulation. Direct measurement of cell shape and contractile forces depicted their important roles in regulating the cell fate decision during neural induction. By dynamically changing the shape of cells using an expandable membrane, we further confirm the possibility to tune the cell fate by solely modulating cell shape. In the second part of the talk, I will discuss how mechanical cues regulate the differentiation of human pluripotent stem cells, including their neural differentiation and anterior-posterior patterning. Together, we provide a novel mechano-chemical model of neural development, which provides novel insights in the biomechanics of embryogenesis and morphogenesis.

Biographical Sketch: Yubing Sun is an assistant professor for the Department of Mechanical and Industrial Engineering at the University of Massachusetts, Amherst. He is also a faculty member of Molecular & Cellular Biology Graduate Program and Institute for Applied Life Sciences at UMass. He received his Ph.D. degree from the Department of Mechanical Engineering at the University of Michigan, Ann Arbor in 2015, and his B.S. degree in Materials Science and Engineering from the University of Science and Technology of China. His Ph.D. work with Professor Jianping Fu established the Hippo/YAP-dependent mechanosensitivity of human pluripotent stem cells. His current research interests include mechanotransduction, stem cell biology, microfabrication, developmental biomechanics, lab-on-chip, biosensing, and ultrasound technologies.

 

 

Abstract: Blood clots are required to stem bleeding and are subject to a variety of stresses, but they can also block blood vessels and cause heart attacks and strokes. We measured the compressive response of human platelet-poor plasma (PPP) clots, platelet-rich plasma (PRP) clots and whole blood clots and correlated these measurements with confocal and scanning electron microscopy to track changes in clot structure. Stress-strain curves revealed four characteristic regions, for compression-decompression: 1) linear elastic region; 2) upper plateau or softening region; 3) non-linear elastic region or re-stretching of the network; 4) lower plateau in which dissociation of some newly made connections occurs. Our experiments revealed that compression proceeds by the passage of a phase boundary through the clot separating rarefied and densified phases. This observation motivates a model of fibrin mechanics based on the continuum theory of phase transitions, which accounts for the pre-stress caused by platelets, the adhesion of fibrin fibers in the densified phase, the compression of red blood cells (RBCs), and the pumping of liquids through the clot during compression/decompression. Our experiments and theory provide insights into the mechanical behavior of blood clots that could have implications clinically and in the design of fibrin-based biomaterials. As a second topic we will consider thermal fluctuations of lipid bilayer membranes. Typically, membrane fluctuations are analyzed by decomposing into normal modes or by molecular simulations. We propose a new approach to calculate the partition function of a membrane. We view the membrane as a fluctuating elastic plate and discretize it into triangular elements. We express its energy as a function of nodal displacements, and then compute the partition function and covariance matrix using Gaussian integrals. We recover well-known results for the dependence of the projected area of the membrane on the applied tension and recent simulation results on the dependence of membrane free energy on geometry, spontaneous curvature and tension. As new applications, we compute elastic and entropic interactions of inclusions in membranes.

Biographical Sketch: Prashant Purohit is currently Associate Professor in the Department of Mechanical Engineering and Applied Mechanics at the University of Pennsylvania. He got his PhD at Caltech in 2002 studying martensitic phase transitions in solids. His current interest is in problems at the intersection of mechanics, physics and biology. Of particular interest are problems in which thermal fluctuations, or entropy, plays a significant role in the mechanics. Examples of such problems include DNA phase transitions, fluctuating filaments and networks and the mechanics of lipid bilayers. Prashant has also worked on nanomechanics of flexoelectric solids and carbon nanotube foams.

Abstract: Multiphase flows are ubiquitous in a wide range of natural processes and engineering applications. Although efforts to compute multiphase flows started as early as the beginning of the computational fluid dynamics (CFD), the progress was rather slow mainly due to the existence of interfaces that continuously evolve in time and often undergo large deformations leading to topological changes such as breakup and coalescence. In the case of confinement, the fluid-fluid interface strongly interacts with the complex channel wall and usually involve small features such as thin liquid films that are difficult to resolve computationally. Multi-physics effects such as soluble surfactant, phase change, chemical reactions, moving contact line and viscoelasticity make the problem even more complicated and challenging for computational simulations. In this talk, I will discuss our work towards addressing these challenges. I will first describe a front-tracking method developed for particle-resolved simulations of multiphase flows, where all relevant continuum length and time scales are fully resolved in all phases. Special emphasis will be placed on treatment of soluble surfactants, viscoelasticity and phase change (droplet evaporation and burning). Sample results will be presented for various multiphase flows encountered or inspired by bio/microfluidic applications. The microfluidic applications generally involve highly laminar low Reynolds number flows but the numerical method is not restricted to low Reynolds numbers and can be directly applied to turbulent multiphase flows at moderate and even high Reynolds numbers depending on available computational resources. Sample results will also be presented about effects of soluble surfactant on weakly turbulent bubbly flows at moderate Reynolds numbers. The talk will conclude with future directions and applications of presented method to large multi-scale and multi-physics problems of practical interest.

 

Biography: Dr. Muradoglu is a professor of Mechanical Engineering at Koc University. He received his BS degree in Aeronautical Engineering from Istanbul Technical University (ITU) in 1992, and MS and PhD degrees both from Cornell University in 1997 and 2000, respectively. He also worked as a postdoc at Cornell for about 18 months before joining the Koc University faculty in 2001 as an assistant professor where he became an associate professor in 2007 and a full professor in 2016. He has had visiting positions at Harvard, Notre Dame and Princeton Universities, and is currently visiting the University of Michigan, Ann Arbor. Dr. Muradoglu’s work has been recognized by multiple awards including the Turkish Academy of Sciences outstanding young scientist award (TUBA-GEBIP) (2009), Middle East Technical University encouragement award (2009) and the Scientific and Technological Research Council of Turkey (TUBITAK) encouragement award (2010). He has been an associate member of Turkish Academy of Sciences since 2012.

Prof. Lucia Gauchia

Assistant Professor, Michigan Technological University

Thursday, May 25, 2017

10:30AM – 11:30 AM

UTEB 476

ABSTRACT

Battery technologies are increasingly being deployed across diverse applications, from portable devices to transportation and residential and grid applications. Consequently, these applications require batteries that can sustain demanding life cycle requirements since batteries can be an asset for multiple services within the same application. In addition, batteries are relied upon for resiliency, and thus, aging is a factor that needs to be considered, especially as battery aging is context-dependent on variations in environmental factors and application demands. In this seminar we will discuss the challenges of battery aging, its multiple scales –cell, module, pack- implications and how we can learn from successful data-enabled approaches applied to ecological systems to better adapt batteries to its application and improve lifetime.

BIOGRAPHY

Lucia Gauchia received her Ph.D. degree in Electrical Engineering from the University Carlos III of Madrid, Spain in 2009. Since September 2013 she is the Richard and Elizabeth Henes Assistant Professor of Energy Storage Systems at the Electrical and Computer Engineering Department and Mechanical Engineering-Engineering Mechanics Department at Michigan Technological University (USA). During 2012 she was a Postdoctoral Research Associate with McMaster University (Canada), working for the Canada Excellence Research Chair in Hybrid Powertrain and the Green Auto Powertrain Program. From 2008 to 2012 she worked at the Electrical Engineering Department at the University Carlos III of Madrid (Spain). Her research interests include the testing, modeling and energy management of energy storages systems. She received the NSF CAREER award in 2017.

Friday, February 17 • 2:30 PM – BPB, Rm. 130

Towards cognitive design assistants and mixed-initiative design of complex systems

Daniel Selva, Assistant Professor

Sibley School of Mechanical and Aerospace Engineering
Cornell University, Ithaca, New York 14853

 

Abstract: Much research in engineering design has focused on making design tools more intelligent by means of optimization, machine learning, and artificial intelligence. The Holy Grail has been to one day be able to do automatic design of complex systems such as spacecraft. This line of research essentially casts design tools as intelligent agents. We thus identify an opportunity to turn into the Intelligent Systems and Human-Agent Interaction fields to get insights about what proved effective in other application areas. Traditionally, the intelligent systems field emphasized fully automated and autonomous agents to tackle complex but structured tasks in well-characterized environments. Increasingly, however, a significant portion of the research has shifted towards human-machine collaboration in order to solve more unstructured tasks in unpredictable environments. This emphasis on mixed teams raises new challenges and questions, such as how to give design agents self-explaining abilities, explore new roles for humans and machines in these collaborations, and facilitate knowledge discovery.

In this talk, I will focus on how to discover and leverage knowledge in mixed-initiative design. First, I will show how the effectiveness of design space exploration algorithms can be improved by using adaptive operator selection algorithms that use domain-independent operators in combination with heuristics encoding expert knowledge. Then, I will show how visual and data analytics can be used to foster discovery and generalization of patterns that appear consistently in good designs. Finally, I will share my thoughts on what I think lies ahead in the exciting new field of design.

 

Biographical Sketch: Daniel Selva received a PhD in Space Systems from MIT in 2012, and he is an Assistant Professor at the Sibley School of Mechanical and Aerospace Engineering at Cornell University and in the Systems program, where he directs the Systems Engineering, Architecture, and Knowledge (SEAK) Lab. His research interests focus on the application of knowledge engineering, global optimization and machine learning techniques to systems engineering, design, and architecture, with a strong focus on space systems. Prior to MIT, Daniel worked for four years in Kourou (French Guiana) as an avionics specialist within the Ariane 5 Launch team. Daniel has a dual background in electrical engineering and aeronautical engineering, with degrees from Universitat Politecnica de Catalunya in Barcelona, Spain, and Supaero in Toulouse, France. He is also a Faculty Fellow at the Mario Einaudi Center for International Studies, and a member of the AIAA Intelligent Systems Technical Committee.

 

For additional information, please contact Prof. Ying Li at (860) 486-7110, yingli@engr.uconn.edu or

Laurie Hockla at (860) 486-2189, hockla@engr.uconn.edu