EXPERIMENTAL DETERMINATION OF FIBER MAT PERMEABILITY OF CHOPPED FIBERGLASS MATS

摘要

This paper presents the results of experimental investigation on fiber bed permeability variation with porosity and injection pressure. Flow measurement experiments were designed to measure fiber mat permeability for chopped fiberglass preforms with various fiber volume fractions. These experiments were performed using a rectangular mold cavity. Several layers of chopped fiberglass mats were used as reinforcement and RL 440 epoxy resin as the working fluid in the experiments. The effects of porosity and injection pressure on fiber bed permeability are investigated. Resin flow in the chopped fiberglass mats was very closely circular, suggesting an isotropic permeability tensor. Still, the analysis was performed based on an anisotropic preform permeability. The results indicate a nonlinear permeability increase with fiber bed porosity (Fig. 1). In Fig. 1 the permeability values in the maximum and minimum flow directions are plotted versus preform porosity. Close values of K 1 and K2 suggests isotropic preform permeability. Note also that permeability increases sharply as porosity increases from 0.8 to 0.84.