Mechanical Engineering Commons^™

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 …

The steady-state behavior of thermal transport in bulk and nanostructured semiconductors has been widely

studied, both theoretically and experimentally. On the other hand, fast transients and frequency dynamics of

thermal conduction has been given less attention. The frequency response of thermal conductivity has become

more crucial in recent years, especially in light of the constant rise in the clock frequencies in microprocessors

and terahertz sensing applications. Thermal conductivity in response to a time-varying temperature field starts

decaying when the frequency exceeds a cutoff frequency Omega_c, which is related to the inverse of phonon relaxation time τ, on the order of …