Tensile properties of ply splice fiber reinforced composite laminates

To fabricate large-scale or unusually shaped composite structures, pieces of reinforcement plies can be spliced to match specific size and shape requirements, forming ply splice structures. The junction of different plies can be considered a defect in the final material, affecting the mechanical properties. In this paper, ply splice carbon fiber reinforced plastics were studied to analyze the fracture mechanism caused by the ply splice, including the effects of the junction geometry and the ply angle. Tensile tests were performed, assisted with digital image correlation for strain distribution analysis and acoustic emission for break mode analysis. The finite element method was also performed using ABAQUS software to study the fracture mechanism. In order to analyze the interlaminar fracture, the interface was simulated with cohesive elements. The results showed that, for a unidirectional carbon fiber reinforced plastics with ply splice, fracturing occurred first at the junction location and then at the interfaces between the splicing layers and the continuous layers. The final strength was determined by the number of continuous layers. The ply-angle had evident effects on the properties of carbon fiber reinforced plastics with ply splices. For a stacking sequence of [± 30°]_5S, the effects of the ply splice on the strength and the fracture mode were similar to the effect with unidirectional plates. For a stacking sequence of [± 45°]_5S, the ply splice had no effect on the fracture mode, but it did decrease the strength slightly. For a stacking sequence of [± 60°]_5S, almost no effect of the ply splice structure could be observed.

PACS (optional, as per journal): 75.40.-s; 71.20.LP