Characterization and Optimization of Composite/Metallic Adhesively Bonded Joints Subjected to Thermal Fatigue

Abstract

Adhesively bonded joints (ABJs) are widely used to mate two or more structural elements. Therefore, to ensure their durability and safe performance, such joints must be carefully designed, especially when they are subjected to harsh environmental conditions. Traditionally, ABJs have been designed using a variety of stress-based approaches. In recent years, however, the use of fracture mechanics (FM) has become increasingly popular for design and analysis of bonded joints. FM offers several approaches for design and analysis of ABJs made of similar or dissimilar materials, and those used in repair of damaged structural components. A summary of an investigation aimed to characterize the response of composite/metallic bonded joints subjected to thermal fatigue by a FM approach is presented. Specifically, the main goal is to quantify the degradation mechanism of such joints by examining the adhesive/adherend interface cracking mechanism. Therefore, a coupled finite element/experimental analysis framework is designed to explore the degradation and failure of the joints. The parameters that actually govern the performance of joints that comprise of fiber-reinforced laminated composite adherends were explored. In addition, an optimization technique has been proposed for improving the longevity and performance of such joints, especially when exposed to cyclic thermal loads. Finally, the use of a relatively inexpensive nanomaterial for enhancing the performance of ABJs is explored and presented.