Resistência e tolerância ao dano em laminados carbono/epóxi com layup tradicional e layup double-double sob impacto de baixa velocidade

Abstract

Optimization of composite material structures, aiming at reducing manufacturing time and costs, decreasing weight, and improving mechanical properties, holds great technological importance and has been the subject of numerous studies. This study investigates the mechanical behavior of two carbon fiber reinforced/epoxy laminates (AS4/8552) with equivalent in-plane stiffness and thickness but different stacking sequences: A [±0/±55]3T laminate, of the type double-double (DD) [±/±]n, and a traditional quadriaxial laminate (QUAD) [03/90/±45]S. Mechanical properties of the laminates were assessed by performing uniaxial compression tests, low-velocity impact tests with three nominal energy levels (30 J, 45 J, and 74 J) and compression after impact (CAI) tests. Additionally, damage mechanisms were evaluated through X-ray computed tomography, and a mathematical model was proposed to the residual strength of the laminates. According to this mathematical model, it was observed that the residual strength of the laminates can be related to the delaminated area, although the damage distribution occurs quite differently between the laminates studied. Ultimately, it was found that the mechanical properties of the two laminates were similar, which supports the possibility of using DD laminates to replace the traditional QUADs, with advantages such as easier fabrication, lower weight, homogenization and optimized stacking sequence.