Damage propagation prediction of composite joint under tensile loading and experimental verification using FBG sensors

Composite joint plays a significant role in the composite sandwich structural connection. However, its complex structure and environmental conditions can lead to difficulties in real-time monitoring. Regarding this, a threedimensional finite element simulation model has been developed for the prediction, propagation and improvement of adhesion failure in an adhesively bonded laminated structure. In this study, a tensile fracture monitoring test under fiber Bragg grating-based monitoring was designed using the Fiber Bragg Grating (FBG) sensors. The simulation, based on the cohesive zone method with Hashin, Chang-Chang, Hou criteria and the mixed criteria, also indicates that debonding of the filler area was the main failure behavior of this composite joint. Using the finite element simulation model based on mixed criterion, the predicted initial and final failure loads have a good agreement with experiments, and the effects of the FBG sensors layout were investigated and discussed on Acquisition and processing of failure signals of composite joint. The findings in this work are helpful to improve mechanical behaviour of composite joint and improve the FBG monitoring to meet the high criteria of the aerospace industry.