COMPOSITE TO METAL JOINTS FOR THE ARPA MAN-RATED DEMONSTRATION ARTICLE

The design, analysis and testing of composite-to-metal joints for the ARPA Man-Rated Demonstration Article are discussed. The first is a com posite-to-titanium sphere joint designed to react sphere membrane stre ss with block compression loading. A series of uniaxial compression te sts to simulate this joint assembly was conducted. Test results succes sfully demonstrated the ability of the joint to withstand block compre ssion loading even in the presence of assembly fit-up gaps. A polymer shimming material (Hysol EA9394) was also evaluated as a means to fill potential fit-up gaps and was found to effectively reduce stress conc entrations resulting from the gaps. The second joint discussed is one between 120-degree segments that make up a stiffener ring for a ring-s tiffened composite cylinder. Joint design includes Hysol EA9394, bolte d-on titanium splice plates, and bonded-on thermoset flange straps. 2D joint tests, single stiffener tests, and sub-scale ring-stiffened cyl inder hydrostatic tests to validate the joint design are described.