Staggered ply discontinuities for tailoring the tensile behavior of hybrid carbon fiber/self-reinforced polypropylene composites: A study of pattern parameters

Abstract

This work explores the potential of discontinuities combined with hybridization in controlling the failure mechanisms of composite materials. Laser cuts, termed as discontinuities, with a predefined staggered pattern were introduced into the carbon layer of hybrid carbon fiber (CF)/self-reinforced polypropylene (SRPP) composites. Three geometrical parameters were used to define the staggered pattern: cut fraction, cut length and step length. The effects of these three parameters on the failure mechanisms of the hybrid CF/SRPP composites under tensile loading were investigated. The three geometrical parameters can be successfully used to: (1) trigger more diffused damage; (2) delay onset of carbon layer fracture; and (3) promote a transition between fiber bundle pull-out and fiber bundle fracture. Comparing to hybrids with continuous fibers, hybrids with the staggered ply discontinuities exhibited a rich diversity of failure mechanisms. The enrichment of failure mechanisms is beneficial for expanding the design space for tailoring the mechanical response of interlayer hybrid composites.