Abstract: Natural phenomena, such as growth, instability, and failure, can be highly dependent upon activation of stochastic mechanisms at the microscale, such as the existence of microscopic imperfections, the action of molecular motors, and the diffusion of constituents. Yet, at the macroscale, astonishing order is often observed. In this talk, I will discuss our recent attempts to bring a deterministic understanding to explain such processes by focusing on the growth of bodies under confinement of an embedding soft matrix. Theoretical models will be complemented by experimental observations at different scales. At the small scales we exploit the growth of biofilm forming bacterial colonies and liquid-liquid phase separation, to examine the influence of confinement in determining the observed morphological transitions; at larger scales Volume Controlled Cavity Expansion (VCCE), via needle induce fluid injection, allows us to study local material properties and the transition between cavity expansion and fracture. 

Biographical Sketch: Tal Cohen is an Associate Professor at MIT. She joined the Department of Civil & Environmental Engineering in 2016 and has a joint appointment in the Department of Mechanical Engineering. She received both her MSc and PhD degrees in Aerospace Engineering at the Technion in Israel. Following her graduate studies, Tal was a postdoctoral fellow for two years at the Department of Mechanical Engineering at MIT and continued for an additional postdoctoral period at the School of Engineering and Applied Sciences at Harvard University. She received the ONR young investigator award and the NSF CAREER award in 2020, and the ARO young investigator award in 2019. Earlier awards include the MIT-Technion postdoctoral fellowship, and the Zonta International Amelia Earhart Fellowship. Her research is broadly aimed at understanding the nonlinear mechanical behavior and constitutive sensitivity of solids. This includes behavior under extreme loading conditions, involving propagation of shock waves and dynamic cavitation, material instabilities, and chemo-mechanically coupled phenomena, such as material growth. 

Abstract: Skin of fast swimming shark species such as Mako are packed with overlapping micro-scale denticles where each denticle is covered with 3-7 ribs. These textures allow sharks to swim faster than other animals in the ocean. Inspired by this capability, two-dimensional symmetric and periodic textures have been considered for the purpose of drag control and reductions of between 7-10% have been reported. Previous research on 2D textures have focused on the effect of the height and spacing of the grooves on the flow and concentrated on V-grooves (triangular grooves). However, the cross-sections of the ribs on shark denticles are concave and the few reported experiments and simulations of textures with curved profiles show that the response of these surfaces cannot be explained as a function of height and spacing alone, and other geometric features play important roles. In addition, 2D textures are simplified models of the shark scales, missing the effect of the overlaps among the denticles.

In this talk, I will examine the effect of the geometric profile of the cross-sections of 2D textures aligned in the flow direction in two cases: first in a small-scale internal flow (Taylor-Couette) and then in a larger scale external flow (boundary layer) setting. I will present the results of the experiments performed using textured covered rotors in a Taylor-Couette cell in the Couette Flow and early transition to Taylor vortex regimes, as well as textured flat samples in a water tunnel in high Reynolds number laminar flows. The custom-designed experiments involve a combination of load/torque measurements parallel with particle image velocimetry of the flow in the vicinity of the textures. I will explore the response of different profiles, and the effect of convex vs. concave cross-sectional shapes, as well as overlaps, on the ability of textures in altering the flow field, frictional loading, and flow instabilities as a function of the geometric features and flow dynamics (i.e. the Reynolds number). I will show that, overall, when compared with the well-known V-grooves, concave profiles (similar to the cross-section of the shark ribs) with height-to-half-spacing less than or equal to unity can enhance the drag reducing ability of textures while convex textures reduce the level of drag reduction.

Biographical Sketch: Shabnam Raayai is a Rowland Fellow and principal investigator at Rowland Institute at Harvard University where her lab is focused on the study of flow around textured and complex geometries. Prior to her current role, she was a postdoctoral associate at the department of civil and environmental engineering at MIT. She received her SM and PhD in mechanical engineering from MIT and have won multiple awards including the outstanding teaching assistant award from the department of mechanical engineering at MIT and Andreas Acrivos Dissertation Award in fluid dynamics from the American Physical Society.

Abstract: Soft robotics aims to develop technological tools to allow people to interact more closely with machines, in a range of settings, from manufacturing, to healthcare, and even our homes. Dielectric elastomer actuators (DEAs) are compliant capacitors which can directly convert an electrical input into mechanical work. DEAs hold the promise of muscle-like behavior, as soft devices that are electrically driven, and easy to integrate with other robotic components. This talk will discuss how muscle-like behavior can be achieved, using knowledge from materials science, electrical engineering, mechanical design, and micro manufacturing. With high performance DEAs, tactile communication tools are demonstrated, with potential medical devices soon to follow.

 

Biographical Sketch: Mihai “Mishu” Duduta is an assistant professor in the Department of Mechanical and Industrial Engineering at the University of Toronto. He completed a BS in Materials Science and Engineering at MIT, then became the first employee of 24M Technologies, a start-up spun out to commercialize a battery technology he co-invented. Four years later he started a PhD at Harvard University, under the guidance of Profs. Robert Wood and David Clarke. His thesis, “Dielectric Elastomer Actuators as Artificial Muscles for Soft Robotic Applications”, included work which won a Gold Award at the Materials Research Society Fall Meeting 2018, and was nominated for Best Paper at ICRA 2018. His postdoctoral work at the University of Minnesota was supported by a Medical Devices Innovation Fellowship, an NSF I-Corps grant, as well as seed funding from the Minnesota Robotics Institute. Working with Prof. Timothy Kowalewski and clinical collaborators, he developed novel miniaturized soft robotic tools for endo-vascular intervention. His research group at the University of Toronto uses an interdisciplinary approach to address fundamental challenges in soft robotics, including actuation, sensing, and energy storage. The work is supported by grants from the Natural Sciences and Engineering Research Council of Canada (NSERC – Discovery Grant, Idea to Innovation), the Canadian Foundation for Innovation, the New Frontiers Research Fund, as well as interdisciplinary seed grants. For his work on steerable micro-catheters, he is the recipient of a 2022 Banting Foundation Discovery Award.

http://s.uconn.edu/meseminar05.13.22

Abstract: In this seminar, Changjie will give an overview of GE Research first, followed by discussion of additive manufacturing. On the additive manufacturing, he will cover additive designs, additive digital tools, additive process monitoring and control, additive supply chain, and additive applications. He welcomes any individual discussions after the seminar.

Biographical Sketch: Changjie Sun has a Ph.D. in Mechanical Engineering. He is currently a senior principal engineer in the Materials and Mechanical Systems Organization at GE Research. He is the technical focal for structure design/analysis and mechanical synthesis. He has been working on jet engine and gas turbine design and analysis for 16 years involving metals, polymer matrix composites, and ceramic matrix composites. Changjie is active in seeking funding opportunities from funding agencies such as DOE and DOD.

http://s.uconn.edu/meseminar05.06.22

Abstract: In this overview of the Engineering Design & Systems Engineering (EDSE) Program at the National Science Foundation, NSF Program Director Kathryn Jablokow will highlight core themes of the program and new opportunities relevant to the engineering design and systems design communities, along with a few key principles for successful proposal writing. In addition, she will discuss her vision for design research, including the implications of treating design as a system and the prospects that open up when we take things to extremes.

Biographical Sketch: Dr. Kathryn Jablokow is a Professor of Engineering Design and Mechanical Engineering at Penn State University and currently serves the National Science Foundation in the Civil, Mechanical and Manufacturing Innovation Division as Program Director for the Engineering Design and Systems Engineering program. Dr. Jablokow is widely recognized for her expertise in cognitive diversity and its impact in engineering education and practice, including manufacturing education and student design experiences. Her recent research includes the use of rapid manufacturability analysis tools to enhance decision-making in engineering design education, as well as the characterization and mediation of manufacturing fixation in design education and practice (i.e., interventions to address an engineer’s overreliance on a specific manufacturing technique). Dr. Jablokow has received many major teaching and research awards, including the W. M. Keck Foundation Teaching Excellence Award, the American Society of Mechanical Engineers (ASME) Ruth and Joel Spira Outstanding Design Educator Award, and multiple Best Paper Awards. Dr. Jablokow is a Fellow of ASME, a Senior Member of IEEE, and a Member of ASEE, Sigma Xi, and the Design Society. She earned her BS, MS, and PhD degrees in electrical engineering from The Ohio State University in 1983, 1985, and 1989, respectively.

http://s.uconn.edu/meseminar04.29.22

Abstract: Implantable Brain Computer Interfaces appear to be heading towards an inflection point: in the past decade the number and frequency of major technological advances and first in human demonstrations of new capabilities has started increasing significantly. The first generations of commercially available products appear to be imminent. They have the potential to become tangible tools to restore lost function and are serious contenders to address a variety of neurological disorders. The real life settings associated with in home use of these technologies lead to reprioritization of existing as well as the emergence of novel practical and fundamental challenges and opportunities. How do we identify and prioritize user, clinician and caretaker needs? What is possible today and what is a realistic technological roadmap that meets those needs. What should public and private investments be focused on?

Biographical Sketch: Dr. Solzbacher is Professor and Chair of the Department of Electrical and Computer Engineering. He also holds adjunct appointments as Professor in Materials Science and Professor of Biomedical Engineering at the University of Utah. He is a fellow of the American Institute for Medical and Biological Engineers AIMBE and a Fellow of the Institute of Electrical and Electronics Engineers IEEE. He is Co-Founder, President and Executive Chairman of Blackrock Microsystems/Neurotech. His research focuses on harsh environment microsystems and materials, including implantable, wireless microsystems for biomedical and healthcare applications, and on high temperature and harsh environment compatible micro sensors. He is co-founder of several companies and member of a number of company and public private partnership advisory and reviewer boards and conference steering committees in Europe and the US. He is author of over 190 journal and conference publications, 5 book chapters and 16 pending patents.

http://s.uconn.edu/meseminar4.22.22

Abstract: Meta-structures are artificially engineered structures designed to exhibit properties not found in conventional materials. By careful design, one can obtain unprecedented control over various physical properties. Examples in mechanics includes structures having unique static and dynamic properties like negative Poisson’s ratio, zero shear modulus and non-reciprocal wave propagation. 

Waveguides transporting energy and information are widely used in bulk and surface acoustic wave devices. They have stringent requirements of a dispersion bandgap and suffer from losses due to localization and scattering at defects or imperfections. In this talk, I will illustrate how these limitations can be overcome by a new class of meta-structures: symmetry protected waveguides. Inspired by recent developments in quantum condensed matter physics, such waveguides allow for wave propagation along an interface or boundary, immune to the presence of structural defects. I will present three examples of different classes of such waveguides. The first example will show a general design paradigm to localize energy in a structure at a desired frequency, while the second and third examples will illustrate backscattering free wave guiding and wave propagation along a channel in structures without any bandgaps. Such waveguides have potential applications in acoustic signal processing, imaging and vibration isolation..

 

Biographical Sketch: Raj Kumar Pal received his bachelor’s degree in mechanical engineering from the National Institute of Technology, Trichy, India, followed by his master’s degree in the same field from the Indian Institute of Science, Bangalore, India. He then worked in industry for a year before starting doctoral graduate studies at the University of Illinois, Urbana Champaign. He earned a Ph.D. in Theoretical and Applied Mechanics, followed by postdoctoral appointments in the School of Aerospace Engineering, Georgia Institute of Technology, and in the mechanical and civil engineering department at the California Institute of Technology. Since 2019, he is an Assistant Professor in the mechanical and nuclear engineering department at Kansas State University. He works broadly at the intersection of solid mechanics and dynamics, investigating fundamental wave propagation phenomena with the goal of novel engineering applications. 

http://s.uconn.edu/meseminar04.01.22

Abstract: Matter (https://www.cell.com/matter) is a new materials science journal from Cell Press (our first issue was July ‘19). Matter is the third offering in the physical sciences from Cell Press, after the successful launches of Chem (2016) and Joule (2017), and an expanding physical sciences portfolio. Our goal is to provide a high impact publication in the field on par with Nature Materials. In this talk, the editor-in-chief, Steve Cranford, will outline the aims and scope of Matter, our internal scientific editorial team, describe our assessment process and outline our framing of materials science. We present our novel MAP scale for materials research progress assessment and provide tips in writing high impact papers and common pitfalls. Come learn about physical sciences at Cell Press and Matter!

Bio: A graduate from Memorial University (Canada), Stanford University (USA), and Massachusetts Institute of Technology (USA), Dr. Cranford was faculty at Northeastern University’s College of Engineering prior to accepting a new role as editor-in-chief for Matter. He has over 50 publications in the field of materials sciences in a range of high impact journals, including Nature and Advanced Materials, with expertise in the area of atomistic simulation, computational modeling, and nanomechanics, encompassing a variety of materials systems, from carbyne to copper to concrete. He would have preferred to have published in Matter, but it didn’t exist. Jumping to publishing in 2018, his goal is to not only make Matter a high impact title in materials science, but also be a key thought leader in academic publishing.

http://s.uconn.edu/meseminar4.8.22

Abstract: Overcoming endemic limitations of existing manufacturing processes can have long lasting socio-economic impacts. I will focus on three innovations that have such an impact. First, I will discuss our work on Intense Pulsed Light Sintering of nanoparticles. I will show how this process alleviates the scalability, damage, and device performance limitations that plague state-of-the-art approaches for manufacturing planar, flexible, conformal, and structural electronics. I will also discuss our discovery of an inherent self-damping behavior in the process, unexpected shape-dependent dynamics of nanoparticle sintering, and the first atomistics-informed scalable model of sintering in nanowire ensembles.

Secondly, I will describe a recent breakthrough in overcoming the throughput-resolution tradeoff that plagues material extrusion-based additive manufacturing (MatEx). I will show how coupling a new toolpath approach with our discovery of continuous material retraction and advancement breaks the above tradeoff, while enhancing economical access to diverse part sizes and geometries and enabling unprecedented resilience to tool failure. I will discuss key parametric trends in the process, new thermal models that reveal the unique temperature history, and potential collaborations with researchers in design and synthesis of materials and in machine learning based control.

Finally, I will describe a magnetics-controlled-plasma based approach to laser micromachining that goes beyond the limits of optical diffraction or wavelength specific-material absorption without modifying the substrate or using near-field techniques. I will discuss key considerations for machine design and process design; the wide materials capability of the process; and the potential to build collaborations in machine learning, control, and process monitoring.

Biographical Sketch: Dr. Rajiv Malhotra obtained his PhD in Mechanical Engineering from Northwestern University and joined Oregon State University as an assistant professor in 2014. He has been an assistant professor at Rutgers University since 2017 where he has established the Advanced Manufacturing Sciences Laboratory, funded by both federal and industry sources. His work has yielded 73 publications including in diverse journals such as Journal of Materials Processing Technology, Journal of Manufacturing Processes, Applied Materials and Interfaces, Advanced Functional Materials, Additive Manufacturing, Nanotechnology, and Sustainable Energy and Fuels. He has been a guest-editor for special issues in ASME and SME journals and is currently an associate editor for Manufacturing Letters, Journal of Manufacturing Processes, and Nature Scientific Reports. He is also a track chair in the ASME Manufacturing Science and Engineering Conference and a scientific committee member in the North American Manufacturing Research Conference. His research and service efforts were recognized by the 2017 Young Manufacturing Engineer Award from the Society of Manufacturing Engineers and the 2018 Associate Editor of the Year Award from the Society of Manufacturing Engineers. Dr. Malhotra is also passionate about integrating sustained mentorship with challenging research opportunities to create a systemic pipeline of students from the undergraduate to the graduate levels.