The effect of thickness on vacuum infusion processing of aramid/epoxy composites for ballistic application

This work addresses the effect of thickness on the vacuum infusion processing of thick aramid/epoxy composites for impact applications. Composites were produced with 5, 8, 13, 18, and 23 plain-weave fiber layers and characterized using ultrasonic C-scan inspections, optical microscopy, density and constituent content analyses, as well as mechanical tests (flexural and short beam). All composite plates presented good reinforcement-matrix homogeneity, with an overall fiber content of about 60%. A reasonable void content was identified by optical microscopy and density analysis, and they were homogeneously distributed. The composites presented high short beam strength values compared with typical aramid/epoxy laminates for impact applications, and ballistic characteristics comparable to those of composites manufactured by compression or autoclave molding. In summary, optimized vacuum infusion processing was shown to be a suitable alternative to produce thick aramid/epoxy plate composites (up to 12 mm), substituting more costly processing routes.