Ellad B. Tadmor

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Professor Tadmor's research focuses on understanding material response from fundamental principles rather than phenomenology. Tadmor studies microscopic processes that lead to macroscopic phenomena such as fracture and plasticity using atomic-scale modeling and multiple-scale techniques. Professor Tadmor is also interested, on a more basic level, in the connection between continuum theory and atomistic models. Some recent specific topics include:

• Continued development and extension of the Quasicontinuum (QC) Method. QC is a multiscale method that makes it possible to simulate large-scale problems using a continuum model while including atomistic resolution where necessary, for example near a crack tip, where atomic-scale processes are important. QC was developed by Tadmor during his Ph.D. work and is currently one of the leading multiscale methods in use in the world. 
• Understanding the microscopic foundations of continuum mechanics. Recent work includes the derivation of expressions for stress and heat flux in atomistic systems based on statistical mechanics. The new derivation provides a unified framework in which all existing definitions for continuum quantities are obtained as limiting cases. This helps to clarify the meaning of these definitions and their range of applicability. 
• Development of the "Knowledgebase of Interatomic Models" (KIM) -- an online infrastructure for assessing the transferability of interatomic potentials. "This project aims to answer the question: When and to what extent can we believe the results of atomistic simulations of materials?" 
• Development of multiscale methods for simultaneously spanning both length and time scales. Current multiscale methods either span over multiple lengthscales (as QC) or accelerate time, but not both. Efforts are currently underway to develop hybrid methods that do both. This will enable predictive studies of complex phenomena such as friction and corrosion cracking. 
• Development of multiscale methods for "objective structures". Objective structures, recently proposed by R. D. James are "molecular structures composed of identical molecules such that corresponding molecules "see" the same environment up to orthogonal transformation." The introduction of objective structures constitutes a breakthrough in solid state physics. Many structures that are not crystalline (like proteins, viruses and nanotubes) are objective structures. The development of multiscale methods for these structures will enable their simulation under realistic conditions involving complex deformation and the presence of defects.