Properties Of Automated Tape Placed Larc (Tm)-Peti-5 Composites

During NASA's High Speed Research Program, robust autoclave processing cycles for LARC (TM) -PETI-5 composites had been thoroughly designed and demonstrated, These involved band lay-up of solvent-ladened "wet" prepregs. Parallel with this work, heated head robotic tape placement technology was also developed. This technology utilized "dry" material forms and represented a different fabrication process which sought to overcome deficiencies such as volatile management and shrinkage inherent in "wet" prepreg processing.In this work, mechanical properties of composites fabricated by heated bead automated tow placement (dry process) followed by autoclave curing were measured and compared with those obtained by hand lay-up/autoclave fabrication (wet process). First, thermal and theological properties of the robotically as-placed (uncured) IM7/PETI-5 lay-ups were measured. Then, a post-cure cycle was designed to give the PETI-5 resin a required 371 degreesC (700 degreesF)/1-2 hr hold to reach full cure, conditions which cannot be duplicated during heated head robotic placement. Open hole tensile and compressive strength and moduli, 0 degrees flexural strength and modulus, RSC dogbone compressive strength, and MZ-MS tensile and compressive properties were obtained on the cured panels. These properties compared favorably with those obtained from composites made by the wet process.