Cocured, Foam Filled Structural Component Design Considerations

Recent high-efficiency designs of composite structures have utilized structural foam as a filler material surrounded by light-weight skins. This alternative type of sandwich construction has many advantages in providing high strength structures. However, special design and fabrication procedures are required to, produce high-quality, structurally adequate components. This paper discusses the design procedures developed at Sikorsky Aircraft to specify least weight solutions utilizing these advanced foams with composite materials. A summary of an elemental test program done to characterize these type of structures and to validate design procedures will be given. Also a discussion of the fabrication procedures will be pro-. vided emphasizing certain dritical parameters that must be maintained in order to assure structural integrity.