Mechanical Comparison of Out-of-Autoclave Prepreg Part to Conventional Autoclave Prepreg Part

Advances in vacuum bag, oven-cure only prepreg material systems allow composite manufacturers to produce detail parts using out-of-autoclave processes that are mechanically equivalent to those of 90 psi autoclave prepreg systems. A well-established baseline exists for a composite structural component fabricated from IM7/8552 autoclave material systems. This detail part was re-made using CYCOM® 5320/T40-800B out-of-autoclave prepreg. All mechanical testing, including short beam shear, combined loading compression, open hole compression, tension and flange bending specimens showed that the out of autoclave system is mechanically comparable to that of the IM7/8552 system. Glass transition testing in two separate areas met the 5320 data sheet requirement of 310°F. Resin content testing in one area of the web showed that the resin content was close to the nominal cured resin content of 33 wt%, at 32 wt%. However, in the flange the resin content was significantly lower, at 27 wt%. Laminate quality of the part is acceptable, with no observed ply wrinkling, voids and resin pooling.