School of Mechanical, Materials and Mechatronic Engineering
SEMINAR Polycrystal modeling: a mechanism-based tool for simulating plastic forming of complex metals
PRESENTER Prof. Carlos N. Tomé WHERE SMART 6-210 DATE Wednesday 29th June 2016 TIME 12:30-13:30
ABSTRACT The 'holy grail' of researchers performing simulations of plastic forming is a constitutive law that: 1) captures anisotropic response, hardening, and their evolution with deformation; 2) can deal with complex deformation histories that extrapolate beyond the strain mode, temperature and rate domains where the model was adjusted; 3) can be effectively implemented in Finite Element boundary value codes. Crystal plasticity (CP) models, based on the physical mechanisms of slip and twinning, meet at least the first two criteria, and are presently being pushed to meet the third criterion. CP models have advanced enormously in the last 20 years as a consequence of increased computational power, and notable advances in experimental methods of automated microscopy, neutron diffraction and synchrotron X-ray diffraction. These methods allow us to characterize material response and microstructure in great detail, challenge our modeling assumptions, and motivate us to develop increasingly sophisticated models.
In this talk I will describe the basics of crystal plasticity and CP models, and will present results of our comprehensive BES research program which focuses on linking modeling and simulation with experimental studies, at length scales spanning from the atomistic to the continuum. I will discuss applications to Magnesium, Zirconium, Beryllium and Uranium alloys, which exhibit hexagonal or orthorhombic crystal structure, high plastic anisotropy, and very characteristic effects associated with twin activity. I will show how this approach improves our understanding of the basic crystallographic deformation mechanisms in hexagonal metals and of the role that they play in plasticity, and leads to an improved modeling capability.
ABOUT THE SPEAKER Carlos Tomé joined the Center for Materials Science (CMS) at LANL) in 1996 and he has been a member of the Structure Properties Relations Group (MST-8) since 1998. Before that he was a Professor at the National University of Rosario (Argentina), and Scientific Staff member at Atomic Energy of Canada. He is currently Laboratory Fellow, the PI of a BES Project on "Role of microstructure on deformation behavior of HCP materials", and a participant in ASC (Advanced Scientific Computing) and CASL (Light Water Reactors) projects.
Carlos Tomé has been involved with Crystal Plasticity modeling of elastic, plastic and creep properties of polycrystal aggregates for the past 30 years. Specifically, development of constitutive equations at the single crystal level including rate, temperature, and neutron irradiation effects for low symmetry metals and geologic materials (hexagonal, trigonal, monoclinic, etc). And incorporation of such behavior into Polycrystal models. He is also interfacing crystal plasticity models with Finite Element codes for simulation of complex forming.
Carlos Tomé publication profile can be accessed at http://scholar.google.com. Citations: 11532 (since 1976), 7211 (since 2010); and h-index: 51(since 1976), 42 (since 2010).
Prof. Carlos N. Tomé
Structure Properties Relations Group (MST-8) Materials Science and Technology Division - MS G755 Los Alamos National Laboratory - Los Alamos - NM 87545 USA e-mail: firstname.lastname@example.org / ph: (505) 665-0892 / fax: (505) 667-8021 ?