An original epoxy-stamp on glass-disc specimen exhibiting stable debonding for identifying adhesive properties between glass and epoxy

An original axisymmetric specimen composed of a concave epoxy-stamp bonded on a glass-disc, which exhibits stable decohesion under traction, is proposed for identifying the adhesive properties, namely the adhesion surface energy, the adhesion peak stress and the decohesion rupture gap between glass and epoxy. Debonding stability is obtained by combining two stabilizing effects of the epoxy-stamp geometry: axisymmetry and concavity. This stamp design is believed to be an important discovery since stable crack propagation is the exception rather than the rule in fracture mechanics. The increasing graph of the traction force vs. the specimen elongation enables to measure the adhesion surface energy upon unloading, calculate the adhesion peak stress and deduce the decohesion rupture gap. Preliminary experiments confirm the stability of the debonding process and show excellent reproducibility.