Study on interlaminar fracture toughness of unidirectional composites

Abstract

Carbon fiber composite is widely used in the nuclear industry and other fields due to their lightweight and high strength. There are various forms of failure in composite, including resin cracking, fiber fracture, and resin fiber interface debonding. At the initial stage of damage, they all exhibit the form of microcracks. As cracks propagate and fuse, they ultimately lead to macroscopic fracture of composite components. For safety reasons, it is necessary to study the fracture toughness of composite. This article uses a combination of winding method and double cantilever beam method to study the interlayer fracture toughness characteristics of high-strength (or high modulus) fiber epoxy resin composite under type I load. Choose a more suitable propagation GIC as a measurement metric. The results indicate that under the same resin matrix, the interlayer fracture toughness of high-strength fiber composite is much higher than that of high modulus fibers, which is related to the high surface chemical activity of high-strength fiber monofilament. Finally, combined with finite element analysis, its application in laminated structures was briefly analyzed.