The Effects of PMMA on Ballistic Impact Performance of Hybrid Hard/Ductile All-Plastic- and Glass-Plastic-Based Composites

The U.S. Army Research Laboratory is focusing on utilizing the materials-by-design strategy in the development of transparent armor systems to achieve lightweight, mobility, enhanced survivability, and lower life cycle costs for the soldiers and ground vehicle protection. The focus of this research is to identify the material parameters that are critical for the ballistic performance of hybrid hard/ductile laminate systems. We evaluated the role of poly(methyl methacrylate), (PMMA), on the impact response of composites consisting of PMMA and polycarbonate, (PC), as well as on the PC-Class-PMMA-PC laminates against the .22-cal. fragment simulator projectile and the 124-gr 9-mm projectile. Increasing the thickness of PMMA improved the overall impact capability of these laminates. Incorporation of PMMA as an intermediate play between the glass and ductile PC appeared to be a very effective approach for the design of glass-plastic laminates. We attributed theses observation to the high strain-rate sensitivity charactenstics of the monolithic PMMA. Preliminary results obtained from the 9-mm projectile testing clearly indicated that the PMMA-based all- plastic laminates maintained a significant amount of residual visibility after impact, which was critical for transparent armor applications. The original document contains color images.