External compaction pressure over vacuum-bagged composite parts: Effect on the quality of flax fiber/epoxy laminates

Abstract

Vacuum bagging allows the removal of trapped air between fabrics layers, extraction of moisture and volatiles, and optimization of the fiber-to-resin ratio. However, during vacuum bagging the compaction pressure is limited to atmospheric pressure, preventing the composite reaching higher fiber volumetric contents and also allows surface porosity to arise, affecting the esthetical appearance of the composite and also its mechanical performance. While the autoclave process has shown to solve these problems, the cost of the equipment is too high for many applications. In the present work, a series of experiments are carried out by compressing unidirectional flax/epoxy vacuum-bagged laminates in a hydraulic press at different pressures. The quality of the laminates is analyzed in terms of surface finish, internal void content, and mechanical properties. The additional compaction from hydraulic pressure is shown to be very effective in improving considerably the overall quality of the composites.

Effects of various porosities on the damage evolution behavior of carbon fiber/epoxy composites using acoustic emission and micro-CT

“…Thus, using the appropriate extra pressure can help to fabricate high-quality composite components during the vacuum-assistant resin infusion process, which has been reported earlier. 37,38 Table 2 also confirms that appropriate extra pressure results in lower porosity.…”

Synergistic effect of ZnO and TiO2 nanoparticles on the thermal stability and mechanical properties of glass fiber‐reinforced LY556 epoxy composites

“…[18] Vacuum bagging method enables evacuation of entrapped air, moisture, and any other volatile particles from the interlaminar spaces within the composite laminate. [19] The bagged composite laminates are subjected to vacuum pressure (1 atm.) curing for 1 h. After 60 min, the applied pressure is vented out and the partially cured laminates are removed from the bag.…”

Hardness, wear behavior and processing time of diluent and non-diluent nanocomposite laminates manufactured by vacuum infusion technique

“…The neat and nanofilled composite laminates were produced by the vacuum resin infusion process. This process consists of three stages: pre-infusion, infusion, and post-infusion [32,33]. Wax was applied to the mold in the pre-infusion stage subsequently, the mold was left to dry.…”

“…Color Transparent Density, g/cm 3 1 post-infusion [32,33]. Wax was applied to the mold in the pre-infusion stage subsequently, the mold was left to dry.…”