| Fiber reinforced elastomers (FRE) or elastomer composites are receiving attention because of the ability to tailor their vibration damping, strength, fracture toughness, and elongation to the range needed.; The current work considers a series of aluminum panels that are laminated with "skins" of graphite cloth, fiberglass cloth, and with chopped fiberglass mat. The reinforcements are impregnated with a series of polyurethane elastomers that range from flexible to rigid in hardness.; For a given type of fiber, the lower durometer elastomer produced the highest loss factor. For a given elastomer stiffness, the stiffest reinforcement produced the highest damping. In general skin loss factors are inversely proportional to the equivalent axial in-plane stiffness of the flexible composite skins. Simple finite element models that assumed all isotropic properties produced natural frequencies slightly lower than experimental results. The study provides valuable experimental data that will be useful in developing flexible or rigid lightweight and cost-effective materials that provide good damping while contributing strength and stiffness. |
