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Recent impact experiments showed the influence a strong or weak interface in a bi-layered PMMA material has on dynamic fracture mechanisms. We show that a linear elastic with brittle damage peridynamic model, which works very well for glass, leads to crack propagation speeds significantly faster than those measured experimentally in the PMMA system. We propose an explanation for this behavior: localized heating in the region near the crack tip (due to high strain rates) softens the material sufficiently to make a difference. We introduce this effect in our peridynamic model, via a bi-linear bond force-strain relationship, and the computed crack …

The finite element method was used to evaluate microstructural strengthening and toughening effects in nanoparticulate reinforced polymer composites (nanocomposites) and in short aligned discontinuous fiber reinforced polymer composites. Nanoparticulate reinforcement is a well-known method of polymer toughening which can greatly expand the range of engineering applications for polymers. However, the mechanisms of nanoparticulate toughening, as well as complementary sub-micron fracture processes, are not well understood. Short, aligned, discontinuous carbon fiber reinforced thermoplastics show promise as a versatile, inexpensive material system with favorable manufacturability, but failure of the associated morphologies is also not yet well explored.

In nanocomposites, two microstructural effects …