Abstract: The thick L-shaped unidirectional carbon fibre reinforced polymer composite laminates (CFRP) were manufactured by the autoclave process. Based on the analysis of macroscopic and microscopic structure morphology, the effects of autoclave pressure on the laminate thickness and fiber distribution were estimated. The results show that the out-of-plane wrinkling and nonuniform thickness distribution arise in the thick L-shaped CFRP unidirectional laminates manufactured by the autoclave process. The resin-rich regions are present between the prepregs. By increasing the autoclave pressure, the thickness of resin-rich regions between prepregs and the wrinkles in the thick L-shaped CFRP unidirectional laminates can be reduced. The thickness compaction, the fiber content difference between different sections and fiber content gradient in the region closing to the bleeder increase with the increasing the autoclave pressure, the thickness of corner section becomes smaller than that of the flat section, and fiber content near mold surface becomes higher if a high autoclave pressure is applied. Close to the mold side, the resin tends to aggregate into the flat/corner transition region.

Key words: thick L-shaped unidirectional laminate, autoclave process, curing pressure, fibre distribution