The effect of the presence of bubbles inside resin on the tensile strength of composites manufactured by vacuum infusion process

The presence of voids in the structure of composites is one of the important manufacturing defects which hasan undesirable effect on the quality of the composite parts. One of reasons the voids appear in a composite plate is thepresence of bubbles in the resin before it is infused. In this research, the effect of bubbles in the resin and degassingbefore the infusion process on the strength of the glass fiber composites is investigated. Four samples infused by a resinwith bubble to resin ratios of ۲%, ۳%, ۴% and ۵%, and two samples manufactured with degassed and non-degassed resin.The composites were cut and tested according to the ASTM D۳۰۳۹. The results showed that non-degassing and thepresence of bubbles decreases the strength of samples from ۴ to ۲۱.۷%. More specifically, each ۱% increase in thevolume of bubbles decreases the final strength of the composite obtained from the tensile test by ۴.۱% in average.