Vitrimer based debondable adhesives for composite structures: Demonstration and computational analysis

With the latest advances in materials science, self-healing vitrimer adhesives with the ability to reform their polymer chain bonds with the application of external heating have emerged. These adhesives allow the manufacture of debond-on-demand and rebond-on-demand joints. This study presents a novel simulation approach that combines phenomenological modeling with finite element models of adhesive joints. The goal is to model the weakening of polymer chain bonds within the adhesive due to heating and estimate the required heating time to reach optimal debonding of the joint. The proposed phenomenological model is fitted to experimental stress-relaxation curves for the adhesive at different temperatures and implemented into finite element models with a user subroutine. Round-butt joints with aluminium adherends were manufactured and debonded at different heating temperatures to validate the proposed model. The finite element simulation results were compared to the experimental stress-displacement curves, showing that the proposed model was able to accurately predict the stiffness reduction of the adhesive for the temperature range that led to optimal debonding with purely cohesive failure in the experiments.