Static fracture tests were conducted, and the critical energy release rate was determined for the unidirectional (O-degree) CLS (cracked lap shear) specimens. The CLS specimens used in this study were mixed-mode specimens made of graphite/peek (thermo...
Static fracture tests were conducted, and the critical energy release rate was determined for the unidirectional (O-degree) CLS (cracked lap shear) specimens. The CLS specimens used in this study were mixed-mode specimens made of graphite/peek (thermoplastic composites). Finite element analysis was performed to calculate GI to GII ratio for the geometry of test specimen, where GI and GII represent the mode I and mode II energy release rate, respectively. The fracture envelop was constructed as a fracture criterion based on the critical energy release rate and GI to GII ratio. The results showed that a linear fracture envelop maybe suitable for CLS specimen.