Correlating Micromorphology and Nanomorphology to High Strain Rate Performance of Nanoparticle Reinforced Polymeric Materials

Abstract

This paper focuses on correlating micromorphology and nanomorphology to the performance of nano-enhanced polymers subjected to blast loading, studying the behavior of these materials at high strain rates, and evaluating the effect of voids’ size and amount on the strain rate sensitivity of nanomaterials. Three polyurea-based elastomeric materials are investigated in this study: unreinforced polyurea, exfoliated graphene nanoparticle (xGnP)–reinforced polyurea, and polyhedral oligomeric silsesquioxane (POSS)–reinforced polyurea. Three-dimensional computed tomography scan images show large amounts of randomly distributed voids in the materials. The study found that POSS-reinforced polyurea has the largest number but the smallest void size among the three tested materials. Computational parametric evaluation is conducted to investigate the effect of such defects on the behavior of these materials. Dynamic nonlinear explicit finite-element code AUTODYN is used to perform three-dimensional analyses for a representative volume element model. The results show that the rate dependence mechanism relies not only on the void ratio but also on void size.