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:
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]