An Elasto-Plastic Investigation of the Peel Test

This work outlines an elasto-plastic investigation of two common peel tests which use high and low yield strength aluminium adherends. An elastic, large-displacement, finite element program has been extended to include elasto-plastic material behaviour. This has been used to analyse both peel tests. The adhesive stresses near the crack tip have been shown to be finite while the corresponding strains remain singular. A failure criterion based on a maximum adhesive strain has been used to predict the relative strengths of the peel test. The amount of energy dissipated in the plastic deformation of the peeling adherends has been assessed by a series of tests and has been shown to be a considerable amount of the total energy supplied to the peeling system. Further, although the two aluminium alloys considered have grossly different yield strengths the energies dissipated in plastic deformation are similar. Material data for the finite element analysis and the plastic work calculations have been obtained from uniaxial tensile tests of both the adherends and the adhesive and actual peel strengths have been measured in a series of peel tests.