Analytical solution for the bond strength of externally bonded reinforcement

Interfacial behavior is critical to composite structures and materials reinforced by externally bonded reinforcement. Numerous empirical and semi-empirical models have been developed for evaluating interfacial bond strength. Analytical solutions have been derived for interfaces with infinite bond lengths, but no closed-form solutions have been derived for the bond strength of an interface with an arbitrary bond length. An analytical solution is derived in this work for the strength of a general externally bonded interface. With the analytical method, the interesting snapback phenomenon in simple pull-off tests is theoretically studied, and an invariant is identified as the condition for it to occur. Furthermore, a methodology is provided to evaluate the interfacial material properties based on a given empirical bond model.