Effects of Accelerated Aging Period of Time at 150°C on Tensile Strength of 3-Dimension-4-Direction Braided/Epoxy Resin Composites

In this paper, the tensile strength of 3-dimension-4-direction braided/epoxy resin composites after accelerated aging for different period of time at 150 degrees C was investigated. The tensile tests of 3-dimension-4-direction braided/epoxy resin composite samples without aging and aged 60 hours, 120 hours, 180 hours, at 150 degrees C were carried out. The damage forms of braided composite samples tested were investigated. The experiment result indicates that the accelerated aging process at 150 degrees C has some effect on the tensile strength of braided composite samples. The average tensile strengths of composite samples aged 60 hours, 120 hours, and 180 hours period of time at 150 degrees C are 92.44%, 91.62% and 84.91% of average tensile strength of braided composite samples without aging, respectively. This means that the tensile strength will be decreased when the aging period of time increases at 150 degrees C. The damage form of samples tested shows that when accelerated aging, the resin in the composite samples is damaged, which makes the adhesive force between fiber bundles and epoxy resin decline, so that the ability of fiber and resin bearing the tensile load together decreases.