On the interplay behavior of fatigue crack growth and delamination of Ti/Cf/PMR polyimide hybrid laminates under overloading

The effect of overload on the fatigue crack growth and delamination of the Ti/Cf/PMR (Polymerization of Monomeric Reactants) polyimide hybrid laminates and the interplay behavior between crack growth and delamination were studied by applying single-peak, multi-peak, and block overloads. The retardation effect was discovered under variable overloads. The mechanism of crack growth and delamination was also analyzed. It was found that the crack grew perpendicular to the fiber direction and the initiation site of delamination always located around the micro-cracks of metal layers. The delamination growth was affected by the maximum stress level and the stress sequence. The interplay between crack growth and delamination on fatigue failure of Ti/Cf/PMR polyimide hybrid laminates could accelerate the crack growth and delamination extension.