Stress Wave and Damage Propagation in Transparent Laminates at Elevated Temperatures

Report No. ARL-CR-639
Authors: Elmar Stra┬┐burger
Date/Pages: March 2010; 58 pages
Abstract: A series of studies has been conducted to visualize damage initiation and propagation in transparent armor materials like Starphire (a registered trademark of PPG Industries, Pittsburgh, PA) soda-lime glass, borosilicate glass, fused silica, and the transparent ceramic AlON. Since transparent armor consists of glass laminates with polymer interlayer and backing, the influence of interlayer type and thickness on damage propagation was also examined. The so-called Edge-on Impact method was applied to visualize stress wave and damage propagation in the previous sets of tests. Two different optical configurations were employed. A regular transmitted light shadowgraph setup was used to observe wave and damage propagation, and a modified configuration, where the specimens were placed between crossed polarizers, and the photoelastic effect was utilized to visualize the stress waves. Pairs of impact tests at approximately equivalent velocities were carried out in transmitted plane (shadowgraphs) and crossed polarized light. The focus of this study was on the investigation of the influence of a layer of strengthened glass or glass ceramic in a laminate target and the influence of elevated temperatures on wave and damage propagation.
Distribution: Approved for public release
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Last Update / Reviewed: March 1, 2010