Testing of a Delta Iv Payload Attach Fitting (paf) Substructure with an Integral Composite Flange

The Air Force Research Laboratory, Space Vehicles Directorate (AFRL/VS), has developed a unique composite Payload Attach Fitting (PAF) shell design. Alliant Techsystems (ATK) and the Boeing Company, Huntington Beach, CA, have developed manufacturing processes and a shell design that incorporates an all-composite forward flange with transverse reinforcement (Z-pinning) at key locations to prevent transverse separation and failure under high bending loads. This paper describes testing equipment, instrumentation, and procedures developed and executed by the AFRL in Albuquerque, NM to demonstrate the structural adequacy of the composite joint under increasing quasi-static load cycles near predicted failure. The overwhelmingly positive results obtained from this design and test program have led to new initiatives to develop modified designs for similar PAF structures.