Loading Rate Effects on the Fracture Toughness of Unidirectional Laminated Composites under mode I Loading

Delamination is one of the most prevalent damages that reduces the stiffness and strength of laminated composites. In this study,the effect of loading rates on the interlaminar fracture toughness of unidirectional laminated composites is investigated. Pure mode Ifracture tests carried out on double cantilever beam (DCB) specimens at quasi-static (300 mm/min) and static (1 mm/min) rates ofloading. The modified beam theory (MBT) method as a conservative data reduction method has been used to calculate the interlaminarfracture toughness DCB specimens. Experimental results show that by increasing the rate of loading to 300 mm/min the steady-stateinterlaminar fracture toughness of laminated composites decreases. Moreover, comparison of resistance curve (R-curve) of DCBspecimens obtained by two loading rates show that the loading rate affect the bridging zone length significantly.

کلیدواژه ها:

Delamination ، Interlaminar Fracture toughness ، Rate of loading ، Fiber bridging