Improving the resistance of a hybrid fiber-reinforced composite material resistant to low-velocity impac

This research studied the effect of adding dioctyl phthalate (DOP) on the low- velocity impact properties of unsaturated polyester composites (UPR) reinforced with hybrid fibers (glass-hemp fibers). To achieve this objective, DOP was added to unsaturated polyester at percentages of 1%, 3%, 5%, and 7%. Samples were prepared reinforced with five layers of random glass fibers and two hemp layers (top and bottom). These samples were then subjected to repeated impact testing three times using a drop ball apparatus. The initial impact tests showed that adding DOP up to 5% improved impact resistance, while increasing the added percentage led to an increase in deformation values. Repeated impact tests (first, second, and third) revealed that all samples remained intact but exhibited varying deformation values. The sample containing 5% DOP showed the lowest deformation percentage at 25.17%. A strong correlation was also observed between the rebound coefficient and the added DOP percentage.