Experimental investigation of buckling and post-buckling behaviour of repaired composite laminates under in-plane shear loading

Damghani, Mahdi; Bugaje, A.; Atkinson, Gary; Cole, D.

Abstract

The performance of Ramped Scarf (RS) and Stepped Scarf (SS) repair schemes for highly loaded composite structures has been extensively studied under compressive, tensile, and flexural loadings. However, there is a lack of research on the buckling and post-buckling behaviour of RS and SS repairs under in-plane shear loading, which is critical for aerostructures. This paper addresses this gap by investigating the buckling and post-buckling performance of these repair schemes. Pristine (P) laminates, RS repairs with a scarf angle of 3°, and SS repairs with an overlap step length of 1/60 were manufactured and tested. The quality of the scarf repairs was inspected using artificial intelligence-based machine vision. Mechanical in-plane shear testing was conducted to evaluate the buckling and post-buckling behaviour of P, RS, and SS laminates. The experimental results indicate that RS repairs demonstrated an average of 35% higher maximum displacement and 12% higher failure load compared to pristine laminates. SS repairs showed 19% higher maximum displacement, and 5% higher failure load compared to pristine laminates. RS repairs excelled in all key mechanical performance indicators, including buckling load, Hooke's stiffness, maximum displacement, and failure load, compared to SS repairs. The failure modes of P, RS, and SS laminates were similar. However, RS repairs exhibited greater susceptibility to repair patch detachment compared to SS repairs.

• Journal Article Type: Article
• Acceptance Date: Sep 20, 2024
• Online Publication Date: Sep 25, 2024
• Publication Date: Dec 31, 2024
• Deposit Date: Sep 26, 2024
• Publicly Available Date: Nov 1, 2024
• Journal: Thin-Walled Structures
• Print ISSN: 0263-8231
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 205
• Article Number: 112489
• DOI: https://doi.org/10.1016/j.tws.2024.112489
• Keywords: Composite Laminate Repair, Stepped Scarf Repair, Ramped Scarf Repair, Shear Buckling, Shear Post-Buckling, Machine Vision
• Public URL: https://uwe-repository.worktribe.com/output/13002015