7 The Influence of Formulation Variation and Thermal Boundary Conditions. . . 49 Table 7.2 Plate sample characteristics Solids loading- Mass Density additive content-sample (kg) (kg/m3) 85-00-1 0.7025 1225 85-00-2 0.6400 1275 85-15-1 0.8148 1421 85-15-2 0.8027 1400 85-30-1 1.0392 1611 85-30-2 0.9200 1604 Fig. 7.1 Representative plate samples of 85% solids loading with (a) 0%(b) 15%and (c) 30% additive content Plates were prepared with 85% solids loading. Three variations were made with 0%, 15%, and 30% weight ratios of aluminum additive content. Solids loading provides the weight ratio of solid crystals to polymer binder in the overall formulation. Additive content provides the weight ratio of spherical aluminum powder to mock RDX crystals (sucrose) in the solids. The mass and density of each plate is presented in Table 7.2. Each plate was tested under convective conditions 43 days after curing to avoid inconsistencies due to aging effects of the polymer composite in the observed mechanical responses. The data presented in the following sections applies to the plates pictured in Fig. 7.1a–c. 7.2.2 Experimental Setup Experiments were performed according to the methodology detailed in Miller et al. [9]. A TIRA 59335/LS AIT-440 electrodynamic shaker was used to mechanically excite the plates at low excitation levels. The parallel short ends of the plate were clamped to the shaker using a plate fixture to simulate clamped-free-clamped-free (CFCF) mechanical boundary conditions with an unsupported sample area of 22.9 cm by 17.8 cm. An accelerometer mounted to the shaker head provided direct feedback to the VibeLab VL-144 vibration controller. The thermal response was recorded using a FLIR A325 thermal camera with a temperature sensitivity of 0.07ıCat 30ıC and an accuracy of ˙2ıCor ˙2%. A Polytec PSV-400 scanning laser Doppler vibrometer was used to record the frequency response of each plate.
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