Strength improvement/optimization methods in adhesively bonded joints: A comprehensive review of past and present techniques

Adhesive bonding is a versatile joining method gaining popularity due to its ability to join variety of metals, nonmetals, and composite materials to achieve lightweight, high-strength structures. Unlike mechanical fasteners that require holes, adhesive bonding creates a continuous bond, resulting in a more uniform stress distribution. It also allows bonding thin materials and dissimilar materials, and creates airtight seals. However, even with these advantages, adhesive joints lack structural redundancy and sometimes strength compared to their mechanical counterparts. This has driven extensive research and development efforts to improve their strength, reliability, and overall performance. The present paper aims to explore both historical and recent advancements in techniques for enhancing the strength of adhesively bonded joints, organizing them in a coherent and systematic manner that can be easily quantified. The paper also presents a comprehensive comparison of the techniques, their dependency on various factors, and guidelines for the optimal choice. This examination could pave the way for novel optimization techniques and data-driven approaches for achieving superior joint performance.