CORNER CONSOLIDATION IN VACUUM BAG ONLY PROCESSING OF OUT-OF-AUTOCLAVE COMPOSITE PREPREGS LAMINATES

摘要

Out-of-autoclave (OOA) prepreg systems are of great interest for the aerospace industry, withrnmechanical properties similar to that of autoclave-processed prepregs. The processing of flat orrnlow curvature parts is generally not problematic with vacuum bag only OOA prepregs. On thernother hand, the moulding of parts with sharp corners often leads to significant thicknessrnvariations and voids concentrated at the corners. In this paper, the mechanisms that govern therncompaction of complex shape composite laminates using OOA prepregs are investigated. Therngoal of this research is to develop guidelines and tools for the adequate design andrnmanufacturing of parts with sharp corners, using vacuum bag only processing methods.rnThickness variation at the corner of L-shape laminates with various radii and flange thicknessesrnwere characterized. The quality of the manufactured parts was analyzed in terms of thicknessrndeviation in the corner region, and the results compared with previous work done on L-shapernlaminates. Laminate thickening was observed at the corner. Results show that thickness variationrnof OOA L-shape laminates depends on tool radius, laminate thickness and flange length. Arnmodelling of the corner thickness deviation was proposed. It accounts for the main deformationrnmechanisms: local compaction pressure differential and interply friction. To quantify theserneffects, the bulk factor was characterized and the interply slip behaviour was measured using arnspecifically designed testing fixture. A general analytical corner compaction model wasrnobtained, and results were compared with the above experimental data.