Center for Advanced Vehicular Systems

Spotlight on Research - Atomistic Modeling

Atomistic modeling offers unique insight into the mechanisms of deformation inaccessible by current lab techniques. With the insight from atomistic modeling physics based quantities are established to inform higher level material models. With nearly 2000 available processors CAVS/CMD is capable of using parallel computing to model large scale molecular/atomistic systems with upwards of 50 million atoms for a wide range of applications. Two specific systems ideal for atomistic models are: i) void nucleation at triple junctions and ii) mechanisms of polymer stretching.

Triple junction voids are a vital component in understanding cumulative damage during fatigue. Voids grow and coalesce, ultimately leading to catastrophic failure. Atomistic modeling offers the opportunity to study the critical stress states which trigger void nucleation. Grain structure, grain size and material defects all influence the material response and are captured using atomistics. Polymers also exhibit behavior at the atomistic level which is important for understanding material damage. By using unified atom theories which lump the hydrogen atoms with the carbon back-bone the chain lengths capable of being modeled greatly increases. Unified atom polymer models directly correlate properties such as bond stretching and rotation, chain breaking and cross-linking to macroscopic properties.

The atomistic models thus capture properties vital for the understanding and physical description of material deformation. The result of a more fundamental understanding of deformation mechanisms is a more sophisticated and applicable macroscopic model.