Experimental Characterization of the Properties of Double-Lap Needled and Hybrid Joints of Carbon/Epoxy Composites

• Main Authors: A. Arnautov, A. Nasibullins, V. Gribniak, I. Blumbergs, M. Hauka
• Format: Article
• Language: English
• Published: MDPI AG 2015-11-01
• Series: Materials
• Subjects: carbon/epoxy composite; mechanical properties; joints; z-pins; hybrid
• Online Access: http://www.mdpi.com/1996-1944/8/11/5410

The effect of through-thickness reinforcement by thin 1 mm steel needles (z-pins) on the static tensile strength of double-lap joints of a carbon/epoxy composite was investigated. Two types of joints—z-pinned and hybrid (including glued ones)—were considered. The joints were reinforced in the overlap region with 9, 25, or 36 z-pins. Comparing mechanical properties of the double-lap joints with the corresponding characteristics of their unpinned counterparts, the z-pins were found to be highly effective: the strength and stiffness of the pinned joints increased up to 300% and 280%, respectively. These improvements were due to a transition in the failure mechanism from debonding of the joint in the absence of z-pins to pullout or shear rupture of z-pins or to the tensile failure of laminate adherends, depending on the volume content of the pins.