2nd Annual MULTISCALE MODELING - Bridging the Gap Between Atomistic and Meso ScalesAugust 13 - 14, 2001 • Holiday Inn • Brookline (Boston), MA USA [ Overview | Agenda | Call for Posters | Register ] View Electronic Brochure (PDF)OverviewRecent advancements in identification of materials behavior through modeling has resulted in reduced materials fabrication costs and increased manufacturing efficiencies. This 2nd international meeting will present the new insights, use and range of multiscale models currently being utilized within industry.Are you in tune with these improvements of multiscale modeling? Learn and share the latest methods and designs of multiscale models from our internationally recognized academic, government and industry leaders who will discuss:* Process and product development of polymers Mark your calendars not to miss this networking opportunity to learn of the latest in multiscale materials modeling and applications. Register today!RELATED LINKSComputational and Theoretical Polymer Science Polymer International Journal of Modern Physics C IOP Journal: Modelling and Simulation in Materials Science and Engineering Modeling and Simulation Magazine AgendaMonday, August 13, 20018:00 Registration, Poster/Exhibit Set Up, Coffee Polymers and Fluids Dynamics8:50 Chairperson's Opening Remarks 9:00 Model-Based Process and Product Development of Polymers The molecular, morphological and interfacial structures are the key intermediates linking the process and product development for almost all polymer products. We employ a wide range of modeling techniques spanning from molecular- to meso- to macro-scale in stochastic and/or deterministic modes, to describe the evolution of these structures from polymerization to processing to performance-testing stages. We will describe the model development and application using an example from our work in the process and product development of Impact Copolymer (ICP) consisting of polypropylene and ethylene-propylene rubber. *In collaboration with Fuminao Watanabe, Japan Polychem Corporation, Yokkaichi, Japan 9:30 Modeling and Simulation of the Failure and Toughness of Polymer/Substrate Bonds The failure of adhesive bonds involves phenomena at many different length scales. A complete model must include breaking of chemical bonds at atomic scales, evolution of complex craze structures at scales of hundreds of atomic diameters, and elastic deformation at the macroscopic scales that control the stress at crack tips. Finite-element methods (FEM) for modeling large-scale behavior are well established, but require appropriate constitutive relations as inputs. These can be difficult to obtain from experiment and analytic theories. In this paper, we describe the role that molecular dynamics (MD) simulations can play in bridging the gap between finite-element calculations and atomic processes. We show how the stress and strain within elemental volumes of a model polymer can be calculated for an arbitrary sequence of imposed stresses and strains. The results provide constitutive relations for FEM calculations. We use this approach to monitor the evolution of crazes and calculate their anisotropic moduli as a function of strain history. We also determine the stress at which the craze fails due to polymer scission or chain pullout. Combining these results with a simple fracture model allows us to predict the toughness as a function of chain length, temperature, cross link density, and the strength of bonds along the polymer backbone. *In collaboration with J. Rottler and S. Barsky, Dept. Physics & Astronomy, Johns Hopkins University. 10:00 Mesoscale Modellings of Multi-Phase Polymer Systems Using Density-Functional Approaches Polymeric materials are typical examples of complex fluids that have mesoscopic structures between the microscopic scales and the macroscopic scales. Using the density functional approaches combined with the path integral formalism, we model the static structures and dynamics of multiphase polymer materials. Computer simulations are performed to predict the structural and relaxation properties of these systems, which can be a useful tool in designing high-functional materials. 10:30 Refreshment Break and Poster/Exhibit Viewing 11:00 Applications of Dissipative Particle Dynamics for the Study of Polymer Blends and Drug Delivery Dissipative particle dynamics is a mesoscale modeling method, which can be effectively applied to study complex systems such as polymer blends. Simulation studies of polymer blends have been performed in order to study the phase separation process and to predict the surface tension and width of the interfacial region. Comparisons with experimental data will be provided. Simulations of drug release in a drug - polymer - solvent system have also been conducted. These studies allow one to develop an understanding of the release process during the polymer dissolution. 11:30 Dynamics of Phase Separation in a Lattice Gas Model Amphilic Fluids A lattice-gas model is used to study the dynamics of phase separation of an amphiphilic fluid as a function of surfactant concentration and quench depth. Two distinct regimes of domain growth are identified. In the first, the growth is bounded and results in a metastable sponge phase. In the second, this sponge phase undergoes nucleation, accompanied by spontaneous micelle formation, ultimately resulting in complete separation of the component immiscible phases. The transition from one regime to the other is described. 12:00 Computational Fluid Dynamics for Practical Engineering Applications Based on an Extended Lattice Boltzmann Method Lattice Boltzmann method is an alternative approach to the conventional hydrodynamic equation computations for mainly fluid dynamics simulations. It is based on a mesoscale representation in that the evolution of fluids is described by a discrete kinetic equation, the lattice Boltzmann equation. This approach offers certain advantages including efficient parallel computing, capable of handling complex boundary conditions, as well as consistent modeling of complex fluids such as those involving multiple phases and components. Exa Corp based on this approach for practical engineering applications has developed a commercial software PowerFLOW. Recently it has become particularly successful in automotive industries in studying aerodynamics and heat transfer properties for new car designs. We are also in the process of developing complex fluids extensions for a wider range of engineering applications and industries. In this talk, we describe the basic lattice Boltzmann algorithm including its extensions to large eddy turbulence simulations. We present results for some know benchmark flow problems as well as for some real world engineering cases. 12:30 Nano-engineering Polymer/Nanoparticle Systems: Simulations at Multiple Scales Hybrid materials consisting of dispersions of nanoparticles in polymer matrices represent a novel class of nanostructured materials. By controlling the geometry and surface chemistry of the nanoparticles, and the polymer/particle and particle/particle interactions, it will be possible to engineer ÒdesignerÓ nanoparticle/polymer systems with specific structure and properties. To guide the design of these hybrid materials and to elucidate how various parameters affect ordering processes and mechanical properties such as the glass transition temperature and elastic modulus, we are performing computational studies of model polymer/nanoparticle systems. In this talk, we describe our approach to combine molecular and mesoscale simulations within a multiscale simulation framework for the rational design of polymer/nanoparticle systems. 1:00 Lunch, Sponsored by The Knowledge Foundation Molecular Dynamics and Grain Growth2:25 Chairperson's Remarks 2:30 Molecular-Dynamics Simulation of Grain Growth and Deformation in Nanocrystalline Materials Extensive molecular-dynamics (MD) simulations of grain growth and deformation in nanocrystalline metals reveal that grain growth involves not only the conventional mechanism of curvature-driven grain-boundary (GB) migration but also the coordinated rotations of neighboring grains so as to eliminate the common GB between them. Our high-temperature deformation simulations illustrate an intricate coupling between GB-diffusion accommodated deformation and grain growth. These insights can be incorporated into mesoscale simulations in which, instead of the atoms, the objects that evolve in space and time are GBs, grain junctions and dislocations, with distinct length and time scales controlled by these microstructural processes. *Work supported by the U.S. Department of Energy, Basic Energy Sciences-Materials Sciences, under Contract W-3l-l09-Eng-38. 3:00 Reactive Molecular Dynamics of Polymer Decomposition Using Ab Initio Potential Energy Surfaces Modeling thermal decomposition of polymers requires a size scale beyond that of electronic structure theory and a reactive capability unavailable in existing codes for classical molecular dynamics. We describe a method of reactive molecular dynamics, MD_REACT, that uses dynamically modified, reactive-surface force fields based on CBS-QB3 ab initio calculations. Results are compared to poly (methyl methacrylate) decomposition data.*In collaboration with Stanislav I. Stoliarov, Dept of Chemical Engineering, University of Massachusetts, Amherst and Marc R. Nyden, Building and Fire Research Laboratory, National Institute of Standards and Technology 3:30 Explorations in Accurate Atomistic, Coarse Grain and Mesoscopic Simulations of Structured Solutions We describe some efforts to deploy and develop accurate atomistic, coarse grain and mesoscopic models for the simulation of structured solutions, focusing on surfactants and phospholipids. The overall approach involves using key information from experiment and more detailed levels of modeling to construct simpler models. *In collaboration with Bob C. Reeder, Bill L. Laidig, Ray A. Crawford, The Procter & Gamble Company; Mee Y. Shelley, Schršdinger Inc.; Sanjoy Bandyopadhyay, Preston B. Moore, Michael L. Klein, Center for Molecular Modeling, Department of Chemistry, University of Pennsylvania. 4:00 End of Day One Tuesday, August 14, 20018:00 Registration, Poster/Exhibit Set Up, Coffee Behavior of Materials8:50 Chairperson's Opening Remarks 9:00 Numerical Identification of the Potential of Advanced Multi-Phase Materials A generic finite-element based approach for predicting the behavior and properties of multi-phase materials comprised of anisotropic, arbitrarily shaped and oriented phases is presented. It is the consistent use of periodic boundary conditions in the course of generating multi-inclusion Monte Carlo configurations, dividing them into morphology-adaptive meshes, and numerical solution for the overall properties that extracts an accurate prediction of the behavior and properties of multi-phase materials from remarkably small computer models. The approach is employed to identify numerically the technological potential of some whisker and platelet filled polymers. 9:30 Multiscale Simulations of the Behavior of Solids Under Extreme Loads Smart materials are increasingly being used in high tech applications such as sensors, actuators, non-volatile memories, etc. The usefulness of these materials lies in their ability to respond predictably to external loads. For small scale devices, these loads can be extremely large, leading to unpredictable response. For these conditions, simple descriptions based on constitutive laws are not adequate. Another important feature is the possibility of chemical reactions in the high-stress environment near a loaded crack tip, which is related to phenomena like fatigue corrosion and embrittlement. In this case, a quantum mechanical approach for simulating electronic behavior is indispensable, as chemical bonds are being broken or rearranged under extreme conditions. The computationally intensive quantum mechanical description is only needed in the regions where chemical activity is likely; the rest of the solid can be described by more conventional and less computationally demanding approaches. Combining methodologies that can describe with adequate accuracy and efficiency the different regions in solids is a challenge to computational modeling. Recent advances in developing such methodologies and their applications to realistic systems, including switching mechanisms in pieozoelectrics and crack propagation in a chemically active environment will be discussed. 10:00 Advanced Materials Development via the Integration of the Various Time and Length Scales of Material Behavior To gain a competitive edge in new markets, many industrial facilities are dedicated to the development of advanced materials. At 3M, the materials modeling expertise focuses on developing and promoting specific materials technologies related to polymers, ceramics and combinations thereof. We will discuss materials innovation via the use of computational methods that capture the various length scales and time scales of materials behavior. 10:30 Refreshment break and Poster/Exhibit Viewing 11:00 Multiscale Modelling and Simulation A major outstanding challenge in the physical sciences is to provide a systematic framework for connecting the atomic and molecular description of matter to the behaviour of matter in bulk, particularly for the hydrodynamic and rheological properties of complex fluids, including surfactants, polymers, and colloids. This talk will describe the progress currently being made towards realising this goal, which is at once of great scientific and industrial importance. Reports on the latest findings to emerge from my groupÕs research on lattice-gas, lattice-Boltzmann and multiscale dissipative particle dynamics, and assess the prospects for achieving closure in this field within the next few years will be discussed. 11:30 Commercial Application of Mesoscale Modeling: The Challenge of Parameterization 12:00 Adsorbed Layers and the Origin of Amonton's Friction Laws Three hundred years ago, Amontons wrote down phenomenogical friction laws that are still used today. They state that the friction is proportional to load, and independent of the dimensions of the contacting surfaces. The molecular underpinning of these laws has remained unclear. Indeed, exact analytic results and experiments in ultra-high vacuum indicate that the static friction between clean crystalline surfaces almost always vanishes in the thermodynamic limit. Of course any surface exposed to air is typically coated by a thin layer of hydrocarbons, water and other small molecules. Simulations are presented that show that these layers naturally produce static and kinetic friction forces that are consistent with Amonton's laws and other aspects of macroscopic experiments1. For example, the friction is only weakly dependent on parameters that are not controlled in most experiments, such as the areal density of adsorbed molecules, their length, the orientation of the surfaces and the direction of sliding. The kinetic friction is of the same order as the static friction and varies only logarithmically with velocity. *In collaboration with Gang He and Martin Muser, Johns Hopkins University1 G. He, M. H. Muser and M. O. Robbins, Science 284, 1650 (1999) 12:30 Lunch on your own Evolution of New Materials1:55 Chairperson's Remarks 2:00 Atomistic Measures of Materials Strength and Deformation Two contributions to the atomistic study of strength of a crystalline lattice are examined. First, stability criteria, previously derived in terms of elastic stiffness coefficients to provide the upper limit to strength, are extended to finite wavelengths by determining the soft modes in the phonon dispersion curves of a deformed but homogeneous lattice. Secondly, an atomistic measure of the thermodynamic dirving force for defect mobility is proposed which does not require dealing with local stresses; in the case of dislocation motion this provides a lower limit to strength. Results from molecular dynamics simulations will be presented to illustrate the usefulness of the concepts. 2:30 Computational Design and Development of New Materials and Processes for Semiconductors Semiconductor devices have experienced in the past like many other materials applications a continuous miniaturization of the feature size, approaching quickly the atomic level. Possible ways to meet the resulting challenges are the introduction of new materials and the refinement of previously used ones on an atomic level. We discuss the development and application of a multiscale tool set from the atomic to the continuum scale in Motorola to allow for timely and cost-efficient design and development of such new materials and processes. 3:00 Mesoscale Modeling of Thermomechanical Processing of Materials This presentation will focus on the development and application of a mesoscale simulation tool to predict the microstructure and microtexture evolution during thermomechanical processing. The approach is based on coupling a finite element deformation model at the microstructural length scale with a Monte Carlo simulation of the evolution of the deformation substructure during annealing. Simulations of static recrystallization will be discussed. *In collaboration with G. Sarma and T. Zacharia, Oak Ridge National Laboratory 3:30 Multiscale modeling in chemical reactors and D. G. Vlachos, Ph.D., Associate Professor, Department of Chemical Engineering and Center for Catalytic Science and Technology (CCST), University of Delaware In this work, a new mathematical framework is introduced for modeling diffusion in nanoporous materials over large length scales while retaining molecular scale information typically captured by molecular simulations only. This framework entails the use of newly developed mesoscopic equations derived rigorously from underlying master equations by coarse-graining statistical mechanics techniques. Comparison of gradient Monte Carlo simulations to solutions of mesoscopic theories shows excellent agreement of the new approach. Homogenization of these equations allows for determination of macroscopic quantities such as mobility and surface tension. Modeling of benzene diffusion through faujasite will be presented as an example of our approach. Call for PostersSelected Oral Presentations and Call for Posters
Conference Sponsorships Networking Event Sponsorships • Cocktail Receptions Workshop Sponsorships Call Alan Abend at (617) 232-7400 ext. 202 or email today for pricing information and customization options. Register
Register me for this exciting conference!
Events | Sponsorship | Exhibiting | Call for Advisors The Knowledge Foundation, Inc. |