Elastic solutions for stresses in compliance-tailored adhesive anchors

Khan, M. A., Wardle, B. L. and Kumar, S. (2022) Elastic solutions for stresses in compliance-tailored adhesive anchors. International Journal of Adhesion and Adhesives, 118, 103227. (doi: 10.1016/j.ijadhadh.2022.103227)

Abstract

Joining of structures via adhesive anchors is of theoretical and practical engineering importance, including anchors that support concrete ceilings in urban infrastructure. Such anchors typically fail due to stress concentrations at the loaded and/or embedded ends, captured by the well-known ‘shear-lag’ model. Herein, such anchors are revisited by considering elastic properties variation of the adhesive along the embedment length in discrete steps, to reduce critical stress concentrations, and thereby minimize the propensity of failure. Initially, a closed-form solution is developed for a system with single-step variation in adhesive compliance along the embedment length (henceforth referred to as double-adhesive bondline), which agrees well with Finite Element simulations. The simplest double-adhesive tailoring is found to reduce the maximum shear stress by 43% while maintaining the super-critical bondlength characteristics of such designs. The theoretical framework thus developed is extended to systems comprising an arbitrary number of discrete adhesives along the embedment length considering, fixed and free boundary conditions of the embedded-end, to allow for parametric evaluation of the adhesive compliance tailoring for optimal stress reduction (maximum shear stress reduces by 46% for triple-adhesive bondline) while maintaining critical-length characteristics. The adhesive tailoring could be effectively applied to anchors with critical-length characteristics by employing a facile double-adhesive bondline with the compliant adhesive near the loaded-end and stiffer adhesive near the embedded-end. The particular case of the well-known Boston tunnel anchor problem is analyzed as an exemplary demonstration of the approach.

• Item Type: Articles
• Additional Information: S.K. would like to thank the university of Glasgow for the start-up grant (Award No: 144690-1). M.A.K wants to thank Mahindra University for funding internal research project on the development of high performance geopolymer concrete.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kumar, Professor Shanmugam
• Authors: Khan, M. A., Wardle, B. L., and Kumar, S.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: International Journal of Adhesion and Adhesives
• Publisher: Elsevier
• ISSN: 0143-7496
• ISSN (Online): 1879-0127
• Published Online: 15 July 2022
• Copyright Holders: Copyright © 2022 The Authors
• First Published: First published in International Journal of Adhesion and Adhesives 118:103227
• Publisher Policy: Reproduced under a Creative Commons License