Search

In the scope of developing a bonded iron-based shape memory alloy (Fe-SMA) strengthening solution, nonlinear deformation in the adherends upon joint failure due to phase transformation and high adhesive toughness is unavoidable. The effect of this nonlinear deformation has not been studied in the case of Mode I failure. In this study, the first experimental and theoretical investigation on Mode I failure of Fe-SMA bonded joints is presented. A new analytical model is proposed and validated using experimental results to gain an in-depth understanding of the influence of Fe-SMA nonlinear material deformation on the joint failure process. The proposed model is shown to be significantly faster than traditional elasto-plastic finite elements using cohesive zone modeling with a minimum compromise to the accuracy. These are observed to result in lower bond strength and a shorter fracture process zone than that of linear elastic adherends using the same adhesive. Neglecting the nonlinear behavior of the Fe-SMA bonded joints can lead to an unconservative joint design, jeopardizing safety. The developed model is aimed at facilitating the development of adhesively bonded Fe-SMA strengthening systems.

Developing a bonded prestressed solution for strengthening structures utilizing an iron-based shape memory alloy (Fe-SMA), is of significant interest. This study is the first systematic investigation of adhesively-bonded Fe-SMA joints to achieve complete cohesive failure, which is an essential prerequisite for bond integrity. The Fe-SMA surface was prepared by combining UV/ozone exposure (UV), sol–gel (SG), and primers (PC, PNC), and the failure mode of the joint was investigated using the floating-roller peel test. Furthermore, the joint durability was studied through artificial aging using a salt spray cabinet. Cohesive failure was obtained for all investigated adhesives, and the effect of every surface preparation step was described. The application of sol–gel was found to be a crucial step in obtaining complete adhesive failure., Structural Integrity & Composites