Delamination propagation in rotating carbon-epoxy composite shaft

Abstract

A carbon-epoxy shaft is fabricated by a filament winding technique. Delaminations are introduced during fabrication. A simple experimental setup for rotation of a composite shaft is designed and fabricated. The composite shaft is subjected to cyclic loadings because of unbalance excitation. The delamination zones are radiographed to determine the crack extension. A plot is generated for crack length versus the number of rotational cycles. Analytical study on crack propagation based on existing laminate plate theory is applied to the composite shaft. The direction of propagation of delamination is compared with Sih's Strain Energy Density Criterion and Maximum Principal Stress Criterion. Using the Paris equation for crack growth, material constants are generated for carbon-epoxy composite subjected to fatigue bending loads due to unbalance excitation in a rotating shaft.