Experimental study of bonded, bolted, and hybrid bonded-bolted single lap shear joints with woven CFRP adherends

Damghani, Mahdi; Saad Khan, Mohammad; Atkinson, Gary A.

Abstract

This paper presents an extensive experimental performance study of bonded joints (BJs), only bolted joints (OBJs) and hybrid bonded-bolted joints (HJs). For each joint type, three test configurations are considered: namely, short, medium and long overlap lengths. In each case, the adherends comprise quasi-isotropic twill woven CFRP. For each joint type/overlap length combination, three specimens are tested for statistical representation. HJs demonstrate 1.4, 1.5 and 1.5 times higher failure load and 1.5, 1.6 and 1.9 times higher stiffness than OBJs, for short, medium and long overlap, respectively. In all test cases, HJs outperform BJs except for short overlaps where BJs outperform both HJs and OBJs. OBJs perform poorly in terms of failure load and Hooke's stiffness. Nevertheless, due to bearing deformation at bolt hole locations, OBJs experience higher failure displacements than BJs and HJs leading to a desirable energy absorption mechanism compared to HJs and BJs. This is thanks to the bearing failure mode of the joint despite much lower failure load in OBJs. It was found that increasing the overlap length generally benefits BJs. However, for medium length overlap specifically, HJs show better performance than BJs. Stress–strain behaviours show a linear behaviour for all test groups with significant joint rotation for OBJs compared to BJs and HJs. Failure mechanism studies presented in the paper show that BJs fail in cohesive failure mode for all test groups. OBJs fail in bearing mode, which is followed by net tension failure. OBJs experience matrix cracking and delamination at bolt hole locations. On the contrary, HJs experience considerably less bearing failure at bolt holes due to the load bearing contribution from the adhesive.

• Journal Article Type: Article
• Acceptance Date: Feb 19, 2024
• Online Publication Date: Feb 23, 2024
• Publication Date: Apr 15, 2024
• Deposit Date: Feb 26, 2024
• Publicly Available Date: Feb 27, 2024
• Journal: Composite Structures
• Print ISSN: 0263-8223
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 334
• Article Number: 117989
• DOI: https://doi.org/10.1016/j.compstruct.2024.117989
• Keywords: Civil and Structural Engineering; Ceramics and Composites
• Public URL: https://uwe-repository.worktribe.com/output/11746756
• Additional Information: This article is maintained by: Elsevier; Article Title: Experimental study of bonded, bolted, and hybrid bonded-bolted single lap shear joints with woven CFRP adherends; Journal Title: Composite Structures; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.compstruct.2024.117989; Content Type: article; Copyright: © 2024 The Author(s). Published by Elsevier Ltd.