ORCID
Madelyn Sloan Berry: https://orcid.org/0009-0001-2934-6860
Degree
Honors Bachelor of Science
Major(s)
Aerospace Engineering
Document Type
Immediate Open Access
Abstract
Composite materials are increasingly used in aerospace structures due to their high strength-to-weight ratio, but their susceptibility to interlaminar fatigue damage remains a critical concern, particularly under mode-II shear loading. This study investigates the fatigue behavior of stitched and unstitched quasi-isotropic carbon fiber composite specimens made of SAERTEX Class-75 non-crimp fabrics and Hexcel 1078-1 epoxy via vacuum assisted resin transfer molding. Global fatigue behavior was analyzed using displacement and crack length cycle relationships derived from compliance calibration methods (CCM), while local behavior was examined using digital image correlation (DIC). Unstitched specimens exhibited a single rapid crack growth associated with unstable propagation, whereas stitched specimens showed staggered crack growth due to crack bridging and arrestment caused by the through-thickness reinforcements. Paris law parameters for unstitched specimens were determined, providing baseline fatigue crack growth behavior. Digital image correlation analysis demonstrated improved crack tracking in stitched regions where CCM limitations were present. Results indicate that stitching modifies crack propagation behavior and improves fatigue damage tolerance in composite laminates.
Date Defended
4-23-2026
Funding Source
Federal Aviation Administration (Award Number G00003737)
Thesis Director
Han-Gyu Kim
Second Committee Member
Wayne Huberty
Third Committee Member
Matthew Peaple
Recommended Citation
Berry, Madelyn Sloan, "Experimental investigation of mode-II interlaminar fatigue damage in stitched and unstitched end-notched flexure carbon fiber composites" (2026). Honors Theses. 191.
https://scholarsjunction.msstate.edu/honorstheses/191
