Fatigue response of glass-filled epoxy composites: A crack initiation and propagation study

This paper presents a comprehensive experimental investigation on the fatigue response of glass-filled epoxy composites when subjected to cyclic loading. Rod-shaped particulate glass fibers in a volume fraction of 0%, 5%, 10% and 15% are reinforced in the epoxy matrix. The mechanical behavior of the resulting composite is studied under monotonic tensile loading and tension–tension cyclic fatigue loading. The undergoing damage mechanisms leading to the crack initiation and its propagation are studied using the in-situ low cycle fatigue testing. The crack initiation behavior and the crack initiation life are found to be affected by different crack initiation sites such as the epoxy-fiber interface, the matrix and the fiber itself. Fractography reveals that the crack coalescence, crack propagation and the failure are largely affected by the varying volume fraction of glass fibers. The specimen with 10% volume fraction is found to exhibit the maximum fatigue life under the applied cyclic loading.