Influence on the delamination phenomenon of matrix type and thermal variations in unidirectional carbon‐fiber epoxy composites

This article analyzes the influence of temperature on the delamination phenomenon in two composites with the same carbon‐fiber reinforcement, but different epoxy matrices. Interlaminar crack initiation and propagation under Mode I with static and fatigue loading are experimentally assessed for different test temperatures: 20, 50, and 90°C. The materials under study are made of AS4 unidirectional carbon fibers and different matrices: one is made of a 3501‐6 epoxy matrix (AS4/3501‐6), whereas the other is made of an 8552 epoxy matrix modified to increase its toughness (AS4/8552). Both composites have a symmetric laminate configuration [0°]_16s. In the experimental program, double cantilever beam specimens were tested under static and fatigue loading. A fractographic study was also performed using a scanning electron microscope on samples obtained from specimens previously tested under static and fatigue loading. A comparison was made of the fracture surfaces at the different test temperatures and the experimental tests' results obtained. POLYM. COMPOS., 36:747–755, 2015. © 2014 Society of Plastics Engineers