Helical and hoop wound graphite/epoxy (Gr/Ep) composite cylinders have been tested under low velocity impact under simply supported boundary conditions, in two phases. In Phase I, the impact energy levels ranged from 1 to 6 ft-lbs, (1 ft-lb = 1.35J) while in Phase II, the impact energy levels ranged from 35 ft lbs-50 ft lbs. Pre- and Post-impact ultrasonic C-scans have been conducted. The fiber bundles and the winding angle(s) are well resolved through the C-scans. Vibration based NDE has been conducted prior to and after impact to determine modal response of the composite cylinders under a simply supported boundary condition. The modal density of the helical wound cylinders is found to be higher than the hoop wound, while the hoop wound cylinders exhibit higher stiffness. The microstructure of some of the cylinders has been studied by sectioning them at impact locations.

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