Analysis of the symmetrical 90 degrees-peel test with extensive plastic deformation

A numerical 2-D study of the symmetrical 90 degrees-peel test (a similar ge ometry to the T-peel test) in which extensive plastic deformation occurs in the adherends is presented in this paper. A traction-separation relation i s used to simulate failure of the interface, and the conditions for both cr ack initiation and steady-state crack growth are investigated. The numerica l predictions for the steady-state peel force are compared with those based on elementary beam theory. It is shown that two competing effects dominate the mechanics of the peel test to such an extent that the results of beam- bending analyses cannot be used to predict the peel force. At one extreme r ange of parameters, delamination is driven by shear rather than by bending, resulting in a lower peel force than would be predicted by beam-bending an alyses. At the other extreme, where delamination is bending-dominated, the constraint induced by the interfacial tractions cause an increase in the pe el force. The numerical results are compared with the results of experiment s in which adhesively-bonded specimens are tested in the symmetrical 90 deg rees-peel configuration. Excellent agreement between the numerical and expe rimental results validates the numerical approach.