Low velocity impact response of non-traditional double-double laminates

A novel family of composite laminates with a simplified stacking sequence and double-double layup [±ϕ/±ψ] n has significant potential to reduce weight and increase strength, while facilitating design optimization and simplifying the manufacturing process. In this study, the low-velocity impact response of a double-double (DD) laminate and a quadriaxial (Quad) laminate of equivalent stiffness and thickness were compared. Carbon/epoxy laminates were produced with stacking sequences of [±0/±50]10 and [03/90/±45/02/±45]2S corresponding to double-double and quadriaxial varieties, respectively. Low velocity impact tests were conducted at 74 J of energy and damage areas were examined using X-ray computed tomography. Compressive strength and compression after impact (CAI) strength were equivalent for the two laminates. However, differences in impact damage morphology were observed and are discussed.