Influence of a depressurized cooling process on the final quality of cured composite structures: an experimental study
摘要
Curing process design is essential for producing high-quality composite parts. In conventional autoclave curing process, components are cooled to a predetermined temperature before pressure release. However, this approach is fundamentally incompatible with emerging curing techniques that utilize in-situ heating sources, where thermal insulation is employed to reduce heat loss and maintain uniform temperature distribution—significantly prolonging the cooling stage. To address this limitation, this study proposes a depressurized cooling process, in which high-pressure gas is vented immediately after curing. Subsequently, thermally insulated components, with vacuum maintained inside the vacuum bag, are removed from the equipment and allowed to cool gradually in ambient conditions until the temperature falls below the predetermined threshold. The effects of this process on cure quality were evaluated through comprehensive experimental analyses, including physicochemical characterization, mechanical testing, and assessment of cure-induced distortion. The results demonstrated that laminates processed via the depressurized cooling strategy exhibited comparable properties to those produced by the conventional pressurized cooling process. Notably, a reduction in cure-induced distortion was observed, particularly when female molds were used. These findings confirm the feasibility and effectiveness of the depressurized cooling strategy, offering a promising alternative for improving process efficiency and dimensional stability in advanced composite manufacturing.