1. Field of the Invention
The invention in general relates to a novel method for making a composite laminate structure and, more particularly, to a structure which has one or more internally embedded vibration damping layers.
2. Background Information
In order to reduce the weight of certain structures, while still maintaining sufficient load-bearing capabilities, extensive use is made of advanced composite materials. Vibration damping of some metallic structures is provided by the structural metallic mass itself, which is no longer available when the structure is formed of a composite material. Accordingly, such composite structure must be provided with a damping arrangement.
One form of advanced damping technique particularly well suited for tubular or box beam structures, for example, is described and claimed in U.S. Pat. No. 5,108,802 assigned to the assignee of the present invention. In that arrangement, the damping is fully encapsulated so as to protect personnel working in the vicinity of the structure from the release of noxious vapors in the event of a fire. Further, the encapsulation protects the internal damping medium from attack by moisture, lubricants oxygen, and the like.
Basically, the aforementioned patent describes a cylindrical structure which has an internal filament-wound constraining layer bonded on the outer and inner surfaces thereof to respective viscoelastic polymer damping layers. The inner damping layer, in turn, is bonded to a filament-wound composite load-bearing member, and the structure is surrounded by an outer composite load-bearing member bonded to the other viscoelastic damping member.
As will be subsequently brought out, the fabrication of such structure is time-consuming and labor-intensive. The present invention provides such structure by a fabrication technique which significantly reduces fabrication time and simplifies the construction thereof.