Study on Fatigue Crack Growth Behavior of Zr702/TA2/Q345R Composite Plate With a Through-Wall Crack and a Crack Normal to Interface for SENT Specimen

Abstract In this paper, the fatigue crack growth behavior of Zr702/TA2/Q345R composite plate with a through-wall crack and a crack normal to interface for SENT specimen are studied. For the through-wall crack, the mutual interference in fatigue crack growth rate is found. The crack growth rate of the through-wall crack on both sides in Zr702/TA2/Q345R composite plate depends on the difference of stress intensity factors amplitude caused by the different positions of crack tips on both sides and the crack growth rate in corresponding homogeneous material. For the crack normal to interface, two crack propagation directions are taken into account. When crack initiates from the lower strength material side, the crack growth rate decreases to the minimum before crack penetrates the interface. After crack penetrates the interface, crack growth rate accelerates continuously. When crack initiates from the higher strength material side, the fatigue crack growth rate generally increases with the crack length. For both crack forms, all experiment results demonstrate that the crack growth rate is dependent on the competition of the stress intensity factor amplitude, the crack growth rate in corresponding homogeneous material and the interface strength. Besides, finite element results show that elastic mismatch results in a significantly change in the distribution of stress intensity factor amplitude.