Title:
Towards enabling high user productivity and high-performance with parallel computing
Abstract:
Recent trends in computer architecture are making high degrees of parallelism as well as heterogeneity ubiquitous. This creates significant challenges to application developers as well as compiler implementations. The effort to develop parallel applications for advanced computational models is extremely high. Further, currently it is impossible to achieve performance portability of high-performance applications from a single version of a program – different code versions are necessary for different target platforms, e.g., for multicore CPUs versus GPUs. A promising approach to easing the burden on applications programmers and achieving high performance on parallel machines is via identifying suitable high-level and domain-specific abstractions. This talk will discuss efforts to develop compiler techniques to automatically transform programs specified using high-level abstractions.
About the Speaker:
Dr. P. Sadayappan is a Professor in the Department of Computer Science and Engineering at The Ohio State University. His primary research interests center around performance optimization and compiler/ runtime systems for high-performance computing, with special emphasis on high-performance frameworks that enable high productivity for application developers in scientific computing. Two recent projects include a polyhedral framework for automatic parallelization and data locality optimization, and the Tensor Contraction Engine – a domain-specific compiler/runtime system to automatically transform high-level specifications into efficient parallel programs, for a class of high accuracy ab initio models in quantum chemistry. Dr. P. Sadayappan obtained a B.Tech from the Indian Institute of Technology, Madras, and M.S. and Ph.D. from Stony Brook University, all in Electrical Engineering.
Faculty Host:Prof. Somnath Ghosh, 203 Latrobe, 410-516-7833, [email protected]
For more information, please contact Jae Hong, 410-516-5033, [email protected]
Title:
PDE Dynamics of Dislocations
Abstract:
The talk will describe a PDE framework to deal with the dynamics of dislocations leading to plasticity in solids. Dislocations are defects of deformation compatibility/integrability in elastic response. The presented framework will be shown to be capable of representing discrete defect dynamics as well as present a natural setting for asking questions related to macroscopic plasticity arising from the underlying dislocation dynamics.
About the Speaker:
Amit Acharya is a Professor in the Mechanics, Materials, and Computing group in the Department of Civil & Environmental Engineering at Carnegie Mellon University (CMU). He received a PhD degree in Theoretical & Applied Mechanics from the University of Illinois at Urbana-Champaign (UIUC) in 1994. Subsequently, he did post-doctoral work for a year at the University of Pennsylvania and then worked for HKS, Inc. in Providence, RI (now Simulia, Dassualt Systemes) from 1995-1998, spending most of his time as a senior research engineer in the ABAQUS Std Development group. There, he was the lead developer of the *Hysteresis nonlinear viscoelastic material model and the S4, fully-integrated finite strain shell element, that are still in use in the ABAQUS general-purpose FE code. From 1998-2000, he was a Research scientist at the DOE-ASCI funded Center for Simulation of Advanced Rockets at UIUC, before joining CMU in 2000.
His broad research interests are in Continuum Mechanics, Mathematical Materials Science, and Applied Mathematics with special emphasis on theoretical and computational continuum dislocation mechanics and plasticity and its coupling to solid-solid phase transformations, liquid crystal mechanics, damage, coarse-graining of nonlinear time-dependent systems, nonlinear shell theory and fluid-structure interaction including mass transfer.
Faculty Host:Prof. Somnath Ghosh, 203 Latrobe, 410-516-7833, [email protected]
For more information, please contact Jae Hong, 410-516-5033, [email protected]
Title:
End-to-end earthquake simulation: From the source to propagation path, site effects, and seismic response of building clusters
Abstract:
This talk will deal with the response of a simple class of building clusters during earthquakes, their effect on the ground motion, and how individual buildings within the cluster interact with the soil and with each other. In order to study this problem it is convenient to first simulate the free-field earthquake ground motion and then incorporate this ground motion as input to the domain that includes the building structures. To this effect, I will describe Hercules, a parallel finite element code developed by the Quake Group at CMU for modeling the kinematic source, wave propagation path and local site effects, and the Domain Reduction Method (DRM), our methodology for incorporating the incoming seismic motion into the analysis of the earthquake response of civil infrastructure in a localized region. As an application, I will then show results of a simulation of the ground motion during the 1994 Northridge earthquake and focus on the coupled response of a set of idealized building models located within the San Fernando Valley in southern California.
About the Speaker:
Prof. Jacobo Bielak received his Civil Engineer’s degree from the National University of Mexico (UNAM), MS from Rice University, and PhD from Caltech. He joined Carnegie Mellon University in 1978, where he is now the Paul Christiano University Professor. His research is in the areas of earthquake engineering and engineering seismology, and, more recently, also structural health monitoring. He was a member of the original Applied Technology Council (ATC) committee that drafted the first tentative seismic provisions for soil-structure interaction in the US based mainly on his work. These provisions are now, in modified form, part of the NEHRP seismic provisions. Recognition for his work includes the Gordon Bell Prize for Special Accomplishment Based on Innovation. He is a Distinguished Member of ASCE and a member of the National Academy of Engineering.
Faculty Host:Prof. Somnath Ghosh, 203 Latrobe, 410-516-7833, [email protected]
For more information, please contact Jae Hong, 410-516-5033, [email protected]
Title
Dental Enamel- a Multi-Scale Modelling Challenge
Abstract
The tooth is a unique functionally graded composite structure at several levels providing a hard and apparently self-healing enamel external shell bonded to a dynamic and resilient dentin core both supported by a vascular and neural network in the tooth pulp. Tooth enamel is nature’s cell derived method for production of a high elastic modulus (~ 90 GPa), hard, wear, and fatigue resistant structure. This presentation will review the micro and meso structure of human teeth as well as studies on their Hertzian contact and Vickers indentation response. The fracture toughness measurements of enamel and dentin by several groups and the need to further explore mechanical response with enamel location and orientation are discussed. Emphasis well be on the role of decussation on enamel properties and likely mechanisms for enamel self-repair of microcracks when teeth are fatigued
About the Speaker
Van P. Thompson, DDS, PhD, is currently, Professor of Biomaterials, Biomimetics and Biophotonics at King’s College London Dental Institute and was previously Chair, Biomaterials and Biomimetics, NYU College of Dentistry. Known for his work on adhesion and bonded bridges at the University of Maryland he has published many articles and made numerous presentations on dental biomaterials in the U.S. and internationally. His current research areas include dentin caries activity, all-ceramic crown fatigue and fracture, modifications of dentin for bonding, engineering tissue response via scaffold architecture and practice based research (PEARL Network).
Faculty Host: Prof. Somnath Ghosh, 203 Latrobe, 410-516-7833, [email protected]
Khairul Bariah Abd Majid: 410-516-5033 or [email protected]
Title:
MECHANICS OF MULTIFUNCTIONAL MATERIALS & MICROSYSTEMS
Abstract:
The area of multifunctional structures has become prominent in the last few years with a number of definitions and concepts being put forth. The most popular definition is a structure that has the ability to perform multiple tasks through judicious combinations of structural integrity with specific functional properties dictated by the system requirements. Some researchers take a rather pragmatic view of multifunctional design by starting with a conventional composite and incorporating the additional layers with specific functionality. Others try to emulate biological systems, in which jointed frameworks and complex materials impart active functionality at multiple length scales. It is hoped that individual material elements are concurrently participating in distinct, beneficial physical processes thereby delivering truly dramatic improvements in system-level efficiency instead of incremental improvements. Among various visionary contexts for developing a new generation of multifunctional structures, the most revolutionary one appears to be “autonomic” systems that can sense, diagnose and respond to external stimuli with minimal intervention. One prominent example has been “self-healing” polymers and composites that mimic the autonomic repair process of biological systems in response to damage. Ever since this novel concept was demonstrated barely thirteen years ago, the worldwide support has allowed focusing extensive research efforts to the subject of autonomic structures in ever-expanding scope. These efforts have established the concepts of “micro-vascular composites for self-cooling,” “neurological system inspired network for self-sensing and actuation,” “self-sustaining structures with integrated power sources,” etc. Such structures would be able to attain each of specific functionalities, adapt to new situations, and perhaps reconfigure them to respond to a perceived threat or change of environment. Each of the cited examples points the values of a truly autonomic system capable of multiple functions to survive its operating condition and environment for longer periods of time than the traditional structures can endure.
About the Speaker:
Dr. Lee is a Program Manager for Mechanics of Multifunctional Materials & Microsystems at the US AFOSR in Arlington, Va. His primary responsibilities include the establishment of science base for integration of emerging materials and micro-devices into future aerospace systems requiring multi-functionality. Dr. Lee joined AFOSR in 2001, following12 years on the faculty of Dept. of Engineering Science & Mechanics at the Pennsylvania State University. He has presided over a number of multi-disciplinary research initiatives, covering a broad range of topics such as “self-healing materials,” “neurological system-inspired sensory network,” “self-sustaining structures with integrated power sources,” “load-bearing antenna systems,” and “biomolecular autonomic materials.” At Penn State, he taught the engineering mechanics courses and performed the sponsored research in the areas of: nanocomposites, penetration failure mechanics, fatigue behavior, and manufacturing science of composites. Prior to his academic career, he had 10 years’ industrial research experience and 3 years’ government research experience.
Faculty Host:Prof. Somnath Ghosh, 203 Latrobe, 410-516-7833, [email protected]
For more information, please contact Khairul Bariah Abd Majid PhD, 410-516-5033, [email protected]
Title:
Integrated Computational Materials Engineering (ICME) for Lightweight Materials
Abstract:
Pacific Northwest National Laboratory (PNNL) is the only Department of Energy (DOE) national laboratory recognized by industry with signature capabilities in Integrated Computational Materials Engineering (ICME), and our research objective is to develop microstructure-based predictive modeling tools in understanding the influences of meso-scale defects and heterogeneities as well as their evolution kinetics on the overall mechanical properties, including ductility and failure, of engineering materials. We are the key bridge between the lower length scale material science and discovery to the larger length scale materials engineering and application. We are currently developing ICME-based predictive capabilities in lightweight metallic materials, including nuclear fuel and structural materials, multiphase advanced high strength steels, Mg castings, aluminum sheets, as well as amorphous glass systems for transparent armor applications. In addition to bulk material property predictions, Dr. Sun’s team has developed an integrated suite of modeling tools considering various manufacturing processes such as cutting (shearing), stretching, forming, welding and joining, in final property predictions. In this presentation, Dr. Sun will present PNNL’s ICME modeling framework and its applications in various lightweight materials including 3rd generation advanced high strength steels, aluminum sheets and Mg casting.
About the Speaker:
Dr. Sun is a Laboratory Fellow and the Technical Group Leader of the Applied Computational Mathematics and Engineering Group at the Pacific Northwest National Laboratory (PNNL). She holds a Ph.D. and two master degrees from the University of Michigan, and has a broad range of experience in the areas of applied mechanics and computational materials. Her expertise lies in applying the mechanics and materials basic principles in solving practical engineering problems associated with advanced materials.
Faculty Host:Prof. Somnath Ghosh, 203 Latrobe, 410-516-7833, [email protected]
For more information, please contact Khairul Bariah Abd Majid PhD, 410-516-5033, [email protected]
Title:
Thermo/Mechanical Length Scales in Metals from Gradient Plasticity and Molecular Dynamics Studies of Nano-indentation
Abstract:
Strain gradient plasticity (SGP) is used to predict size effects in the deformation behavior of metals at the micron and submicron scale and it is appropriate for problems involving small dimensions. Size dependency of the mechanical properties is a consequence of increase in strain gradients inherent in small localized zones which lead to geometrically necessarily dislocations that cause additional strengthening. The current SGP theories do not give sound interpretations of the size effects if a definite and fixed length scale parameter is used and variable length scale which changes with the deformation of the microstructure that depends on dislocation evolution, temperature, and rate effects in addition to the grain size is required to address the real behavior of the materials. Moreover, the observed indentation size effect cannot be well explained by the SGP theories.
The correlation of the data obtained from MD and SGP simulations of nano-indentation is used to guide the process of identification of characteristic thermo/mechanical length scales in metals. The research studies aim at developing fundamental understanding of critical issues such as: i) the role of characteristic length scales, temperature, and microstructural features (grain size, grain boundaries, texture, etc.) on the yield and flow stresses of nanomaterials, ii) the enabling knowledge of grain boundary engineering aimed at achieving microstructures with desired properties, and iii) advancing the multiscale and physical-based theoretical and computational models to capture the observed mechanical response and scale-dependent characteristics.
About the Speaker:
George Z. Voyiadjis is the Boyd Professor at the Louisiana State University, in the Department of Civil and Environmental Engineering. Voyiadjis is a Foreign Member of the Polish Academy of Sciences. He is the recipient of the 2008 Nathan M. Newmark Medal of the American Society of Civil Engineers and the 2012 Khan International Medal for outstanding life-long Contribution to the field of Plasticity.
Voyiadjis’ primary research interest is in plasticity and damage mechanics of metals, metal matrix composites, polymers and ceramics with emphasis on the theoretical modeling, numerical simulation of material behavior, and experimental correlation. Research activities of particular interest encompass macro-mechanical and micro-mechanical constitutive modeling, experimental procedures for quantification of crack densities, inelastic behavior, thermal effects, interfaces, damage, failure, fracture, impact, and numerical modeling.
He has two patents, over 260 referred journal articles and 17 books (10 as editor) to his credit. He gave over 350 presentations as plenary, keynote and invited speaker as well as other talks. Over fifty graduate students (30 Ph. D.) completed their degrees under his direction. He has also supervised numerous postdoctoral associates. Voyiadjis has been extremely successful in securing more than $15.0 million in research funds as a principal investigator from the National Science Foundation, the Department of Defense, the Air Force Office of Scientific Research, the Department of Transportation, and major companies such as IBM and Martin Marietta.
Faculty Host:Prof. Somnath Ghosh, 203 Latrobe, 410-516-7833, [email protected]
For more information, please contact Khairul Bariah Abd Majid PhD, 410-516-5033, [email protected]
Title:
Time-Reversal and Reciprocity Breaking in Electromechanical Metamaterials and Structural Lattices
Abstract:
Recent breakthroughs in condensed matter physics are opening new directions in band engineering and wave manipulation. Specifically, challenging the notions of reciprocity, time-reversal symmetry and sensitivity to defects in wave propagation may disrupt ways in which mechanical and acoustic metamaterials are designed and employed, and may enable totally new functionalities. Non-reciprocity and topologically protected wave propagation will have profound implications on how stimuli and information are transmitted within materials, or how energy can be guided and steered so that its effects may be controlled or mitigated.
The seminar will briefly introduce the state-of-the-art in this emerging field, and will present initial investigations on concepts exploiting electro-mechanical coupling and chiral and non-local interactions in mechanical lattices. Shunted piezo-electric patches are exploited to achieve time-modulated mechanical properties which lead to one-directional wave propagation in one-dimensional mechanical waveguides. A framework to realize helical edge states in two identical lattices with interlayer coupling is also presented. The methodology systematically leads to mechanical lattices that exhibit one-way, edge-bound, defect-immune, non-reciprocal wave motion. The presented concepts find potential application in vibration reduction, noise control or stress wave mitigation systems, and as part of surface acoustic wave devices capable of isolator, gyrator and circulator-like functions on compact acoustic platforms.
About the speaker: Massimo Ruzzene is a Professor in the Schools of Aerospace and Mechanical Engineering at Georgia Institute of Technology. He received a PhD in Mechanical Engineering from the Politecnico di Torino (Italy) in 1999. He is author of 2 books, 140 journal papers and about 180 conference papers. He has participated as a PI or co-PI in various research projects funded by the Air Force Office of Scientific Research (AFOSR), the Army Research Office (ARO), the Office of Naval Research (ONR), NASA, the US Army, US Navy, DARPA, the National Science Foundation (NSF), as well as companies such as Boeing, Eurocopter, Raytheon, Corning and TRW. Most of his current and past research work has focused on solid mechanics, structural dynamics and wave propagation with application to structural health monitoring, metamaterials, and vibration and noise control. M. Ruzzene is a Fellow of ASME, an Associate Fellow of AIAA, and a member of AHS, and ASA. He is the Program Director for the Dynamics, Control and System Diagnostics Program of CMMI at the National Science Foundation.
Title:
Magnetics + Mechanics + Nanoscale = Electromagnetics Future
Abstract:
Efficient control of small scale magnetism presents a significant problem for future miniature electromagnetic devices. In most macroscale electromagnetic systems we rely on a discovery made by Oersted 200 years ago where an electrical current through a wire creates a distributed magnetic field. While this concept works well at large scale, it suffers significant problems at volumes below 1 mm3. One approach to control nanoscale magnetic states is spin-transfer torque (STT). However, experimental measurements on STT memory devices indicates that 100 fJ is required to reorient a bit of memory with an energy barrier of about 0.5 aJ, i.e., at 0.0005 percent efficiency. Therefore, new nanoscale approaches are needed for future miniature electromagnetic devices.
Recently, researchers have explored strain-mediated multiferroic composites to resolve this problem. For this material class, a voltage-induced strain alters the magnetic anisotropy of the magneto-elastic elements. These strain-mediated multiferroics consists of a piezoelectric material coupled to magneto-elastic elements to transfer electrical energy to magnetic energy through a mechanical transduction. The coupling coefficient (energy transferred) in piezoelectric materials (e.g., lead zirconate titanate, PZT) is approximately 0.8 while the coupling coefficient in magneto-elastic materials (e.g., Tb-Dy-Fe, Terfenol-D) is of similar magnitude, 0.8. Thus, the amount of energy to overcome a 0.5 aJ bit barrier is potentially only 0.8 aJ, or an efficiency of about 60 percent, neglecting line losses.
This presentation reviews the motivation, history, and recent progress in nanoscale strain-mediated multiferroics. Research descriptions include analytical and experimental work on strain-mediated multiferroic thin films, single magnetic domain structures, and superparamagnetic particles. The results indicate efficiencies orders of magnitude superior to STT approaches and presents a new approach to control magnetism. Discussions of future research opportunities and novel applications are included.
About the speaker: Greg Carman received his Ph.D. degree from Virginia Polytechnic Institute and State University in 1991. He joined the Mechanical and Aerospace Engineering Department at the University of California, Los Angeles, in 1991. He is the director of a new National Science Foundation Engineering Research Center entitled Translational Applications of Nanoscale Multiferroic Materials (TANMS) and is engineering director of the Center for Advanced Surgical and Interventional Technology in the Department of Surgery at UCLA. He is an associate editor for the Journal of Intelligent Material Systems Structures and for Smart Materials and Structures. He received the Northrop Grumman Young Faculty Award in 1995 and three best paper awards from the American Society of Mechanical Engineers (ASME) in 1996, 2001, and 2007. He was elected Fellow of the ASME in 2003 and was awarded the ASME Adaptive Structures and Material Systems Prize honoring his contributions to smart materials and structures in 2004. In 2015 SPIE honored him with the Smart Structures and Materials (SSM) Lifetime Achievement Award. Presently his research interests focus on analytical modeling, fabrication, and testing of multiferroic (magneto-electric) materials and developing devices for medical applications.
