Abstract: A method and apparatus for damping the vibration of a reinforced skin structure (e.g., the fuselage of an aircraft) over a wide frequency range (wideband) in order to reduce the vibration and transmitted noise, and improve the sonic fatigue life, of the structure is disclosed. Wide range damping is accomplished by viscoelastically attaching constraining elements, which can be continuous or segmented, to the skin and to the reinforcing members that support the skin. The viscoelastic attachment between the constraining elements and the reinforcing members directly damp the vibrations of the reinforcing members; and, the viscoelastic attachment between the constraining elements and the skin directly damp the vibrations of the skin.

Abstract: A method and apparatus for reducing the low to mid frequency interior noise of a reinforced skin structure, such as the cabin of a jet aircraft, by reducing the vibration response of the structure to low to mid frequency disturbances is disclosed. Interior noise is reduced by forming the structure such that the skin panels bounded by reinforcing components have a higher fundamental frequency than the combined bending and tuning fork frequency of reinforcing components with spaced apart legs that support the skin; and, damping the bending, tuning fork and torsional vibration of the reinforcing components. Damping is accomplished by bridging the spaced apart legs of the reinforcing components with rigid elements, viscoelastically attached at either end to the legs. Preferably, the viscoelastic attachment is via flanges that extend outwardly from the legs.