Experiments of the adhesion behavior between an elastic beam and a substrate

Adhesion between the lower surface of an elastic beam and the flat surface of a substrate during a loading–unloading cycle is experimentally investigated. In the presence of adhesion, it has been theoretically explained that the force curve for the loading and the unloading coincides with each other because reversible thermodynamic work of adhesion, which is the work to separate a unit area of the adhered surfaces, is considered. In the experiment, however, the work of adhesion was apparently different between the approaching (loading) and the receding (unloading), and the force curves did not coincide with each other. Therefore, the theory is modified considering the difference of the apparent work of adhesion between them. Maximum tensile force is theoretically obtained as a function of the displacement at the transition point from approaching to receding.