SBIR/STTR Phase I:FUNCTIONALLY GRADIENT PARTIAL INSERT DEVELOPMENT FOR THIN-SKIN SANDWICH COMPOSITE STRUCTURES

This Small Business Innovation Research (SBIR) Phase I project will develop an innovative system for reliably and inexpensively attaching medium- to heavy-weight equipment to thin-skin composite sandwich structures. This will be accomplished with proprietary metallic foam (patent applied) and polymeric partial inserts with functionally graded stiffness. This is different from the stiffness of the sandwich material and is set to the stiffness and strength required to carry the equipment. By varying the stiffness of the insert from low to high, it will be possible to carry the weight of the equipment without damaging the polyvinyl chloride (PVC) core material. Inserts of metal foam and polymer composite with varying density and stiffness will be fabricated by a patented extrusion, free-form fabrication technology. Due to the materials low density, less than one or two pounds of the attachment material will be of adequate volume for a composite attachment system. Thus, the material cost of the attachment system will be small relative to the cost of a traditional sandwich composite structure. Potential applications are anticipated in manufacture of vehicles for commercial transportation, e.g., buses, trains, small crafts, and aircrafts.