Local bending moment as a measure of adhesion: The cantilever beam test

It was recently proposed (Goussev, O. A., Zeman, K. and Suter, U. W., J. Ad hesion 56, 45 (1996)) to characterize the joints between materials directly by the maximum bending moment, M-max, borne just prior to delamination (de lamination moment). This alternative to the energy-release-rate approach wa s first introduced for the blister test configuration. Here we extend this idea to a cantilever beam test. We suggest, therefore, to evaluate the bend ing moment in the cantilever-beam experimental setup with an elastic upper plate through direct measurement of the curvature of the upper plate in the vicinity of the separation line. For the profile measurement and determina tion of the exact location of the delamination line, the projection-moire t echnique was employed. The methodology was tested on measurement of adhesio n of an epoxy adhesive to steel. It was shown that the value of the maximum bending moment remains approximately constant during the delamination, ind icating that this quantity is a physical characteristic of the joints betwe en materials.