Abstract: Our ability to manufacture now greatly exceeds our ability to design. Engineers are no longer merely inconvenienced by inefficient trial-and-error design; rather, they are nearly incapacitated by the vast space of possible designs afforded by Advanced Manufacturing (AM) technologies. There are no systematic methods to design systems with such complexity, especially those that exhibit nonlinear, transient, multiscale, and multiphysics phenomena with uncertain behavior.

The opportunity and need to fundamentally transform design is one of the most compelling frontiers of engineering research.  To this end, the Lawrence Livermore National Laboratory’s newly instantiated Center for Design and Optimization is developing algorithms that can optimize immensely complex systems in High Performance Computing (HPC) environments. The complexity comes from two sources, design and physics. Design complexity refers to the intricate shape and material layouts that are made possible by today’s AM technologies; it can take the form of structural composites with intricate morphologies. It also refers to the multifunctional metrics that we optimize, e.g., we maximize electromagnetic response subject to local strength and global mass constraints. And finally, it refers to constraints dictated by the AM processes to ensure manufacturable designs. Physics complexity comes from the mathematical models that are used to predict the performance of our designs. Such models require the solution of partial differential equations that contain complicated nonlinearities, transients, multiple scales, multiple physics, and uncertainties. We iterate through the design space, solving the physics equations using numerical methods. Because our design Degrees-Of-Freedom (DOF) and physics DOF are in excess of 100 million, we must develop efficient, large-scale HPC algorithms. This effort will enable engineers to optimize designs that exhibit unprecedented performance relative to current practice; it is not optional: it is an absolute necessity if we want to drive future innovation.  The work offers immense challenges in engineering, math and HPC.

Biographical Sketch: Daniel A. Tortorelli is the Director for the Center of Design and Optimization at the Lawrence Livermore National Laboratory and the George B. Grim Professor Emeritus at the University of Illinois at Urbana-Champaign (UIUC).  He received his BSME degree from the University of Notre Dame du Lac in 1984 and his MSME and PhD degrees from the UIUC in 1985 and 1988.  His professional career began as senior project engineer for General Motors Advanced Engineering Staff.  In 1990, he embarked on an academic career at UIUC and stayed there until he retired in 2016 to begin his new career at LLNL.

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.