August 1, 2014.
TufFoam is a low density, high impact tolerant polyurethane foam with good high voltage breakdown developed at the Sandia National Laboratories. Identically shaped samples have been produced with various formulations and production conditions. Eight different variables were studied. Our aim is to compare the density variation of the material when produced and processed under distinct conditions. The density of TufFoam is determined using radiographic imaging. We extract the foam density by fitting the radiographic density of each step in a plastic step wedge with 10 steps from 0.1 to 1.0 inches and applying the resulting equation to convert each pixel in the radiograph to an image based on inches. A total of 28 samples were radiographed with a source to sample distance of approximately 53 inches. The 28 samples were separated into 12 different groups; each group of samples was produced under identical conditions. The results varied depending on the variables in which the samples were produced. We observed that when samples were fabricated under certain conditions the resulting images and histograms showed a uniform density distribution. When made under other conditions samples were produced with a non-uniform density distribution. Furthermore, certain variables resulted in samples with distinct and thicker skin layer compared to the interior portion of the sample. We will discuss the effect of the variables on the homogeneity and density of the samples.
Physics | Statistics and Probability
Sandia National Laboratory/California (SNL)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013 and Grant No. 0934931. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).