The role of interface fiber orientation on the delamination growth of ADCB E-glass/epoxy laminated composite specimens

In the present study, the effect of interface fiber orientation on the delamination behavior of ADCB specimen is investigated. In other words, in this research, the R-curve behavior of ADCB specimen during the crack initiation and its propagation have been studied. For this goal, ADCB specimens with stacking sequences of [016//08] and [015/90//0/07] were selected in order to eliminate the effect of remote ply orientation on the R-curve behavior. So firstly, E-glass/epoxy laminated composites were manufactured by the hand lay-up method. In the next step, fracture tests on ADCB specimens were conducted using a universal test machine. The test results show that more energy is needed to pull out fibers which are perpendicular to the crack growth direction. So, as a significant result, it can be concluded that ADCB specimens with 0//90 interface have greater initiation and propagation of interlaminar fracture toughness than the specimens with 0//0 interface. In addition, according to the R-curve behavior, the bridging zone length of ADCB specimens with 0//0 interface is greater than that of the 0//90 interface. Based on the findings, this is due to more interweaving of two adjacent layers of the delamination interface with the same fiber orientation.