Internal characteristics analysis of woven/unidirectional composite angle part by VBO process

Abstract

This study focused on the internal characteristics analysis of woven and unidirectional composite angle parts by vacuum bag-only (VBO) process. The composite parts with angle-bend were made by the interleaved layup of prepreg and dry fibers under vacuum only consolidation. To understand the fiber volume content (Vf) variation of the angle part under different process conditions, a visualized diagram of Vf distribution of the angle part was constructed. In this VBO process, the Vf at the corner area of the angle part increased for the convex angle-bend and decreased for the concave angle-bend. The Vf increased proportionally with the thickness in both plate and corner areas of the angle part. For analysis of porosity for the angle parts, the porosity decreased with the increase of the part thickness, while it increased with the bend angle. The same conclusions were also observed as the caul plate was used in the processing. The lead caul plate was found to have more effect in porosity reduction in the corner areas. A simple scoring mechanism was proposed to quantify angle part porosity. The part with convex angle-bend has lower porosity than that with concave angle-bend. The porosity was analyzed in this study for angel parts with convex or concave angle-bend by the interleaved prepreg/dry fiber VBO process, which provided information for design of angels for the complicated composite parts.