Evaluation of Interlaminar Fracture Toughness on the Mode II of a Ultra High Molecular Weight Polyethylene and CFRP Hybrid Composites

It is essential for the most general means to utilize composite material in order to improve both of the strength characteristics and weight reduction of structures. Especially fiber reinforced composites are used in a wide range of area from the appearance of cars, ships, and aircraft to the structural parts by changing the fiber’s weaving, stacking, and shaping according to their intended uses. However various defects can occur due to the occurrence of bubbles in the fibers and matrix, depending on the pressure and temperature conditions in the autoclave. Typically, the delamination may bring out due to interlaminar fracture in the laminated composites. Many studies on the interlaminar fracture of CFRP composite material have been carried out so far. However, there is little research on hybrid composites with UHMWPE that can compensate for the low toughness of CFRP. Therefore, in this study, the interlaminar toughness behavior of mode II fracture was evaluated for the laminated UHMWPE/CFRP hybrid composite by using 4ENF test. From the results, GIIc, which represents the interlaminar fracture toughness as a critical energy release rate, was obtained as 1.56 kJ/m², 1.52 kJ/m² and 1.40 kJ/m² for a0/L=0.3, 0.4 and 0.5, respectively. It shows that the energy release rate decreases as the initial crack length increases.