Experimental Evaluation of Fatigue Properties of Carbon Fiber/Epoxy Matrix Interface and Numerical Simulation of Transverse Cracking under Cyclic Load

This study aims to experimentally evaluate the S−N relationships between the interfacial tensile stress applied to the carbon fiber/epoxy matrix and the number of applied loading cycles when interfacial debonding is initiated. Tension – tension fatigue tests of single carbon fiber embedded specimens were performed, and digital image correlation observations were conducted during the fatigue tests. Changes in the microscopic apparent strain distribution during fatigue tests were utilized to detect the initiation of fiber/matrix interfacial debonding. The results demonstrated that the fiber/matrix interfacial tensile strength degraded depending on cyclic loading. Fatigue crack growth simulation was also performed based on the finite element method considering the strength degradation of the fiber/matrix interface.