Compaction of e-glass fabric preforms in the Vacuum Infusion Process, A: Characterization experiments

An experimental procedure was designed to realistically characterize the compaction behavior of e-glass fabric preforms during initial application of vacuum and mold filling stages of Vacuum Infusion (VI). To mimic VI, the loading (compaction) was done on a dry preform, and the unloading (decompaction) was done after the preform was saturated with resin. When fabrics were wetted at constant full compaction pressure, a significant decrease in thickness was observed for the random fabric, but not for woven and biaxial fabrics. The rate of change of thickness, ∂h/∂t had different signs and order of magnitudes when various constant compaction pressures were applied during fiber relaxation stage. Thus, previous compaction-mold filling models based on static relationship between thickness and compaction pressure do not appropriately simulate the compaction physics of VI. Time-dependent database of this study is a useful and straightforward tool to model VI, as demonstrated in Part B of this study.