Viscoelastically damped reinforced skin structures

Abstract

Viscoelastically damped reinforced skin structures wherein a sandwich skin having a relatively thick core is supported by structural elements, such as stringers and frames, are disclosed. In one form (FIG. 1), a main skin (15) is supported by stringers (13) that are in turn supported by frames (11). The skin, stringers and frames are securely attached to one another by any suitable means, such as a bonding adhesive, rivets, bolts, etc. Located between the stringers are core layers (17) formed of honeycomb or foam materials. A first plate (21) overlies each core layer and extends to the flanges of the adjacent stringer. A second plate (25) overlies each adjacent pair of first plates. The core layer is viscoelastically attached (19 and 23a) to the skin and the first plate; and, the first plate is viscoelastically attached (23b, c and 27a, b) to the stringer flanges and to the second plate. Alternatively, a single plate (49, FIG. 3) can overlie the core layers (47) and the stringers (43). In an alternative form of the invention (FIG. 4), the main skin (63) is located between the stringers (65) and the frames (61); and, is securely attached thereto. An outer skin (67) is viscoelastically attached (68a, b and 73) to the stringers (65) and to core layers (69). The core layers (69) are located between the main (63) and outer skin (67, and pairs of adjacent stringers (65). The core layers are also viscoelastically attached (71) to the main skin (63).