Damping of filament wound composite cylinders

Graphite epoxy filament wound composite tubes were fabricated both with and without an imbedded layer of rubber, dynamically tested, and analyzed to investigate their damping characteristics. The filament winding process used IM-6 graphite fibers with an anhydride resin system, wet winding over an aluminum mandrel, and an oven cure in a rotisserie. Four different configurations were manufactured: a control configuration, one with an added layer of rubber, one using a modified resin system, and one with both an added layer of rubber and a modified resin system. Two independent modal tests were conducted. The data indicated that the mode shapes as well as the frequencies changed with the addition of a layer of rubber. The constrained layer damping with rubber dramatically increased the modal damping coefficients. Mode shapes from an FEM analysis of the undamped tube were correlated with the measured mode shapes. About half of the first thirteen computed mode shapes correlated with measured mode shapes. (Author)