Pullout characteristics of functionally graded and degraded adhesive anchors

Kumar, S. , Khan, M.A., Wardle, B. L. and Reddy, J.N. (2023) Pullout characteristics of functionally graded and degraded adhesive anchors. European Journal of Mechanics - A/Solids, 99, 104950. (doi: 10.1016/j.euromechsol.2023.104950)

Abstract

Three-dimensional axisymmetric elasticity solutions for pull-out stresses in bonded anchors with spatially stiffness-varying adhesive are presented. A stiff rod embedded in a semi-infinite rigid half-space through an adhesive layer, representing a general anchor problem is analysed. The adhesive layer is considered to have a smoothly varying stiffness over the entire or a portion of the embedded length. Two cases of particular engineering relevance are considered: (i) stiffness grading of the bondlayer to enhance performance while retaining the critical length characteristics of bonded anchors and (ii) modulus reduction of the bondlayer representing adhesive degradation proximal to the loaded end. Theoretical solutions are developed adopting a stress function approach in conjunction with a variational method that compare well with 3D axisymmetric Finite Element (FE) results. Both theoretical and FE results indicate that the maximum shear stress in the adhesive decreases over 60% for a graded bondlayer for the parameters considered here without warranting a longer embedment length. In contrast, spatially-stiffness-degraded bondlayer reduces shear stress peaks significantly but warrants a larger embedment length to enable shear-dominated stress-transfer. A design map showing the critical embedment length required for degraded bondlines as a function of fractional embedment length over which bondline is regarded to have degraded is presented. In addition, interfacial fracture behavior of the tailored and degraded adhesive anchors were examined through FE analyses and noted that the tailoring reduces the energy release rate but has the potential for enhancing damage tolerance. The findings of the study indicate that the stiffness-tailored and -degraded bondlines significantly redistribute the stress field with concomitant influence on stress-transfer and interfacial debonding characteristics of bonded anchors.

• Item Type: Articles
• Additional Information: S.K. would like to acknowledge the start-up grant provided by the University of Glasgow (Award No: 144690-1).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kumar, Professor Shanmugam

Creator Roles

Kumar, S.: Conceptualization, Methodology, Validation, Formal analysis, Investigation, Resources, Writing – original draft, Writing – review and editing, Supervision

• Authors: Kumar, S., Khan, M.A., Wardle, B. L., and Reddy, J.N.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: European Journal of Mechanics - A/Solids
• Publisher: Elsevier
• ISSN: 0997-7538
• ISSN (Online): 1873-7285
• Published Online: 20 February 2023
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in European Journal of Mechanics - A/Solids 99: 104950
• Publisher Policy: Reproduced under a Creative Commons License