Strain rate effect on CRALL under high-velocity impact by different projectiles

A fiber-metal laminate (FML) is a hybrid laminate that is mostly used for aircraft, automobiles, and defense industry applications. The carbon fiber-reinforced aluminum laminate (CRALL) is an advanced FML and has a very high specific strength. To investigate the effects of strain rate and projectiles' nose shape on the ballistic limit of the CRALL, a series of dynamic explicit analyses were performed at high-velocity impact (HVI) by using flat, hemispheric, and sharp-nosed projectiles at three distinct strain rates (1 s(-1), 100 s(-1), and 1000 s(-1)). A progressive damage model based on damage initiation and damage propagation was developed for this numerical study and implemented in the ABAQUS software. At HVI, the damage modes and failure processes of the carbon fiber-reinforced polymer (CFRP) in the CRALL were investigated using Yens' criteria. The damage behavior of aluminum (Al) plates in the CRALL under HVI was determined by the Johnson-Cook (J-C) model. A cohesive surface based on bi-linear traction-separation law was utilized in between the Al plate and CFRP composite lamina to investigate the delamination in inter-laminar. The obtained results reveal that the CRALL has a high ballistic limit, either for high strain rates or for flat-nosed projectiles. The strain rate has significant influence on the CRALL ballistic limit velocities for the flat-nosed projectile as compared to other projectile configurations.