Single and repeated low-velocity impact response of E-glass fiber-reinforced epoxy and polypropylene composites for different impactor shapes

This study focuses on the effects of low-velocity impact (LVI) response of thermoset (TS) and thermoplastic (TP) matrix-based composites. In this study, the effects of the impactor shapes on the low-velocity impact response of the composite panels that produced from different matrix was investigated. Unidirectional E-glass fiber fabrics with an areal density of 300 g/m2 as reinforcement and epoxy matrix were used to produce TS composite. The vacuum-assisted resin infusion molding (VARIM) method was used to manufacture composite panels. The thermoplastic composites were manufactured with E-glass fiber-reinforced polypropylene prepregs. The tensile strength of TS matrix-based composites is higher than TP matrix-based composites that have the same fiber volume fraction. Despite being under the same impact energy, the TP specimens possess higher perforation threshold than TS specimens. The shape of the impactor significantly affected the perforation threshold. Besides, the impact number that caused perforation reduced dramatically in conical impactor. The repeated impact number that caused perforation is 36 for hemispherical (HS) impactor, but it is only 3 for conical impactor for polypropylene matrix-based composite. Moreover, a significant effect of fiber volumetric ratio on impact resistance was observed. The perforation threshold of glass fiber-reinforced polypropylene composites for 40% and 50% fiber volume fraction are 61 and 98 J, respectively. The perforation threshold of TP and TS specimens for HS impactor that has the same stacking sequence is 61 and 55 J, respectively.