My name is Robert Carson. I finished my PhD at Cornell University under the advisement of Professor Paul Dawson in 2018. I am currently a postdoctoral research staff member at Lawrence Livermore National Laboratory. My main focus is within the field of computational solid mechanics working on exascale type codes.
Work related to my thesis centered around characterizing intragrain/intra-crystal deformation mechanisms and how these mechanisms evolve and form networks through a polycrystalline material during cyclic loading. I’ve accomplished a majority of this work through the use and expansion of various different single crystal elasto-viscoplastic models. Overall, my thesis work has led to me having a strong background in a number of fields ranging from: continuum mechanics; numerical methods (nonlinear FEMs, krylov subspace methods, ODE solvers); far-field high energy diffraction; high performance computing through the use of MPI and OpenMP; and data analysis/visualization of large data sets. It has also exposed me to various dimensionality reduction methods, statistical inference methods, graph theory, and image analysis such as connected component labeling.
During my time at Cornell, I spent a great deal of my time collaborating with Professor Matthew Miller and Dr. Mark Obstalecki for a combined set of experiment and modelling studies. They were responsible for running high energy x-ray diffraction experiments on copper samples using both far-field and near-field techniques. Through our combined modelling and experimental approach, we were able to show the strengths and weaknesses of various different micro-mechanical hardening laws. This interaction really imparted onto me the need for more combined modelling and experimental efforts. Without these efforts, it can be incredibly easy to get lost in the weeds on the modelling side and forget about how real materials actually behave. New experimental methods also allow us to verify and obtain new single crystal elastic constants along with varying plasticity parameters. On the modelling side, we can provide the experimentalist a wealth of detailed information, once we know our models limitations. Current experimental methods on average are either only able to return grain average information while in-situ or ex-situ intragrain data. Simulations therefore provide a valuable complement to experiments in that they are able to return highly resolved intragrain data for a wide number of parameters.
My current work is related to the creation of an exascale velocity based nonlinear solid mechanics finite element code. The code itself is largely focused on crystal plasticity type problems. A majority of this work expands upon the domain knowledge expertise that I accumulated during my time while at Cornell.