In this study the effect of embedded optical fibers on the interlaminar fracture toughness of composite laminates was investigated. The interlaminar fracture toughness is represented by critical energy release rate. The DCB(double cantilever beam) tests were performed to obtain energy release rate for mode I($G_I$) and ENF(end notched flexure) tests were performed to obtain critical energy release rate for mode II($G_II$). Two stacking sequences of $[0_18{X}0_18]$ and $[0_6/90_4/0_8{X}0_8/90_4/0_6]$ were used for composite laminates, where \{X\} is the location of embedded optical fibers. Specimens with embedded optical fiber sensors with different space and orientation were fabricated and tested using 10-ton MTS servohydraulic testing machine.
The interlaminar fracture toughness of specimens with embedded optical fibers oriented in 0˚ was not affected by embedded optical fibers for both mode and mode II. The interlaminar crack of specimens with embedded optical fibers oriented in 90˚ was arrested by embedded optical fibers. So the critical energy release rate of ENF test specimens with embedded optical fibers oriented in 90˚ was increased when the crack was arrested. But the energy release rate of DCB test specimens with embedded optical fibers oriented in 90˚ was not always increased when the crack was arrested.
