Outfitting Attachment Systems for Composite Sandwich Structure (MSC P1B16-211)

"Sandwich panels will be used extensively in topside structure for future Navy ships. One missing piece of technology needed for this application is a robust, easy-to-install method for attaching the myriad of outfitting items required in a ship. The MSCapproach to solving this problem is to design an insert that can transfer pull-out loads directly to the core material. Loading the core removes the possibility of ripping off the facesheet in an overload condition. Stress analyses have been used tooptimize the insert so that stress concentrations are minimized, and the theoretical maximum load can be achieved in practice. Testing in the Phase I program established the validity of the concept. The Phase II program focuses on performing sufficienttesting that the Navy can have the same level of confidence in this system as they have for existing attachment systems. In addition, development work will be performed to reduce the fastener cost and improve the ease of installation.BENEFITS: Thepotential market for the device is large. It is estimated that the composite helicopter hangar alone uses 20-30 thousand screws. Next generation surface combatants such as DD(X) are likely be built with a high percentage of composite structures. The useof composites is being driven by life-cycle cost considerations, reduced crew size, stealth, and weight. Thus, the surface ship market alone is sufficient to drive a healthy market for the inserts. The same outfitting considerations also occur in therecreational boat and yacht markets."