MEASURING HYDRO-STATIC DEPENDENT CONSTITUTIVE BEHAVIOR OF ADHESIVES USING A BEND SPECIMEN

A simple bend test and associated equations that determine, simultaneously, both the tensile and compressive uniaxial stress-strain behaviour of a bulk adhesive are presented. From this, the ratio of the flow stress in compression to tension (S) can be found. Such data are required if a meaningful elasto-plastic stress analysis of an adhesive joint is to be carried out. Experimental results for both the tensile and compressive stress-strain data are obtained for an epoxy specimen using this technique. The tensile data are compared with the results from uniaxial tensile tests on flat dumbell specimens of the same material and the good correlation that is found indicates. that this is a reliable technique. Values of the ratio (S) for this adhesive are calculated as a function of both strain hardening and work hardening parameters. These results indicate that this technique complements standard test techniques and provides an elegant method not only of obtaining the ratio (S) but also of deriving uniaxial stress-strain curves.