On the impact strength of adhesive bonded pin-and-collar joints

Nowadays, the adhesive technology is gaining relevance in industrial sectors where impact operating conditions are very common. At the same time, tests on cylindrical joints represent a well-established method for determining the static strength of structural adhesives. This work aims at assessing the impact properties of structural adhesives by means of cylindrical joints. The investigation involved two adhesive formulations (an epoxy resin and an anaerobic) and has been carried out under static, quasi-static and low-velocity impact conditions. The main outcomes of the work are: (i) the pin-collar specimen is well suited to analyzing the impact properties of adhesives; (ii) both adhesives showed a dependence of the strength and stiffness properties on the strain rate; (iii) the epoxy product showed a greater impact toughness than the anaerobic. In appendix, the authors report the tuning procedure of a CZM numerical model in a commercial FE package, based on the experimental results.