Joshua Stowe Successfully Completes His Masters Thesis Defense

CONGRATULATIONS to Joshua Stowe on the successful completion of his Masters thesis entitled "Material property predictions of polymers using molecular dynamics simulations." Josh's advisors were Dr. Maciej Kumosa and Dr. Peter Laz. Please see the attachment for the complete presentation.

ABSTRACT
Nanoscale materials can exhibit different physical properties compared to their macroscale counterparts. The use of multiscale modeling of materials has been recognized as a tool to predict both physical and chemical properties of materials between the nanoscale and macroscale. Thus, the primary goal of this research was to utilize molecular dynamics, one of the multiscale modeling techniques, to predict of the mechanical behavior of polyethylene.

Stress-strain relationships and the Young’s modulus were calculated for low density polyethylene at several molecular weights and high density polyethylene models at a single molecular weight. Probabilistic Monte Carlo methods were used in order to identify possible sources of uncertainty in the mechanical property predictions.

Probabilistic methods identified the effects of uncertainty on mechanical property predictions. Significant variability, on the order of 1000% of the mean, in stress-strain relationships and the Young’s modulus predictions were caused by variations in polymer configuration and density, the non-unique nature of molecular dynamic calculations of equilibrium, and the molecular weight of the model used for analysis.