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Low Rate Dynamic Fracture Simulation of Toughening in Polymers via Highly Ordered Nanoplatelets

GARRETT NYGREN, and RYAN KARKKAINEN

Abstract


This study employs finite element based computational fracture mechanics methodologies to evaluate microstructural toughening effects in epoxy reinforced with highly ordered nanoplatelets (achieved through magnetic field application during processing) to invoke crack redirection in addition to toughening. Despite a large amount of scientific study, much work remains to be done to understand and quantify nano-scale toughening mechanisms. Herein, simulations of active fracture mechanisms on the micron scale are used to identify and quantify various toughening or weakening effects due to nanoplatelet inclusions. This study develops strategies for determining critical strain energy release rates (GC) from simulation and examines some of the challenges involved therein. Simulation on the micron scale of fracture is critical to understanding different micro-scale toughening mechanisms and their relative contributions, but quantitative correlation to continuum level properties is demonstrably challenging. The current work examines successful strategies for bridging macro-scale and micro-scale simulation, such as replacing artificial damping with dynamic simulation of inertial effects to maintain computational fidelity and accurate physical representation. Methodologies are validated with experimental data at the macro-scale. Validated methodologies are applied to fracture simulations of highly ordered nanoplatelet inclusions in an epoxy matrix, and a parametric study quantifies the potential for toughening and crack redirection.

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