Dynamic Flexural Modulus and Low-Velocity Impact Response of Supercomposite^TM Laminates with Vertical Z-Axis Milled Carbon Fiber Reinforcement

Abstract

In work reported here, the dynamic properties and low-velocity impact response of woven carbon/epoxy laminates incorporating a novel 3D interlaminar reinforcement concept with dense layers of Z-axis oriented milled carbon fiber Supercomposite TM prepregs, are presented. Impulse-frequency response vibration technique is used for non-destructive evaluation of the dynamic flexural modulus (stiffness) and loss factor (intrinsic damping) of woven carbon/epoxy control and Supercomposite TM laminates. Low-velocity punch-shear tests were performed on control and Supercomposite TM laminates according to ASTM D3763 Standard using a drop-weight impact test system. Control panels had all layers of 3K plain woven carbon/epoxy prepregs, with a dense interlaminar reinforcement of milled carbon fibers in Z- direction used in designing the Supercomposite TM laminate—both having same areal density. Impulse-frequency response vibration experiments show that with a 50% replacement of woven carbon fabric in control panel with milled carbon fibers in Z direction dynamic flexural modulus reduced 25% - 30% (loss in stiffness) and damping increased by about the same 25% - 30%. Low-velocity punch-shear tests demonstrated about 25% reduction in energy absorption for Supercomposite TM laminates with the replacement of 50% woven carbon fabric in control panel.