Impact Damage Response of Composite Materials at Cryogenic Temperatures

Abstract

*† A state of the art impact facility has been developed to study the ignition of polymer matrix composites in liquid oxygen. The facility utilizes several advanced data acquisition techniques including the novel flash sensor presented in this paper. The flash sensor is synchronized with the force signal to reveal exactly when ignition occurs during an impact event. Individual damage formation events are then related to the flash. Damage development results during impact are also presented from testing at cryogenic and room temperatures. At cryogenic temperatures, the specimens in this study tend to crack vertically at the edge of the indentor then grow outward to the sample edge. At room temperature, the specimen in this study develops internal matrix cracks and delaminations that do not propogate to the specimen boundaries. These differences in damage are also detected on the force-time and force-deflection data from impact testing.