Properties of automated tape placed LARC-PETI-5 composites

摘要

During NASA's High Speed Research Program, robust autoclave processing cycles for LARC-PETI-5 composites had been thoroughly designed and demonstrated. These involved hand 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 head automated tow placement (dry process) followed by autoclave curing were measured and compared with those obtained by hand lay-up/antoclave fabrication (wet process). First, thermal and rheological 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°C (700°F)/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 meduli, 0° 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.