Experimental measurements of interface shock viscosity in hydroxyl-terminated polybutadiene (HTPB)-ammonium perchlorate (AP) material system are performed using mechanical Raman spectroscopy (MRS) combined with laser pulse shock loading. First, HTPB-AP interface level shock wave propagation is studied using the cohesive finite element method. The difference in the shock behavior of the analyzed HTPB-AP interfaces from that of the bulk AP and HTPB material is highlighted by numerical simulations of impacting a single AP particle in an HTPB-AP sample in three different ways: (1) a flyer plate is used to impact the whole HTPB-AP sample; (2) a flat impacter is used to impact the middle of AP particle embedded in HTPB matrix directly; and (3) a HTPB-AP interface is directly impacted with an impacter of radius 1 μm. Shock wave rise time at the interface is shown to differ for the three different impact modes. Based on the simulation results, a combined MRS and pulse laser-induced particle impact test is used for measuring shock viscosity at HTPB-AP interfaces. It is observed that by changing the chemical composition of the interface, shock viscosity can be altered. A modified finite element model with viscous stress based on shock viscosity values added to the stress equation is then used for the shock impact simulation of an HTPB-AP material system. A power law relation was obtained between shock wave rise time and the shock viscosity.
Thin films of Ba(Zr0.15Ti0.85)O3 were crystallized in situ at several different oxygen background pressures and temperatures. The optimal temperature and pressure for obtaining films with smooth surface morphology and good electrical properties was found to be 675 °C and 300 mTorr, respectively. Films grown at this temperature were found to have a Pr of 3.31 μC/cm2 and an Ec of 93.5 kV/cm. Low field dielectric measurements and C-V measurements were performed in order to study the dielectric behavior of the films. A tunability of ∼45% was recorded on the films.
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