The Law of Similarity on the Fracture Behavior of Continuous Fiber-Reinforced Composite Laminates with Different Ply Thicknesses

Abstract

The macroscopic fracture behavior of composite laminates is now being clarified to be controlled by the extension of microscopic cracks. On the basis of released elastic strain energy accompanied by microcrack extension, we present simple equations which enable us to predict the fracture behavior of the laminate with arbitrary ply thickness by using the experimental results of the laminate with standard ply thickness. We come to the conclusion that the damaged region ahead of notch tips in laminates extends to a size proportional to the ply thickness under the same apparent critical stress intensity factor. The difference in the maximum apparent critical stress intensity factor sustained by the laminate with different ply thicknesses is also quantitatively examined. The predicted fracture behavior is in good agreement with the experimental results of continuous glass fiber-reinforced epoxy cross-ply laminates with three different ply thicknesses.