High strain-rate compression and tension behaviour of an epoxy bi-component adhesive

The dynamic behaviour of the bonded joints is influenced by the dynamic mechanical properties of the material of adherends and adhesives. The literature contains plenty of information about the dynamic mechanical properties of many structural materials (especially metals), obtained through different test types. Conversely, the study of the dynamic mechanical properties of the adhesives is not so common. The purpose of this work is to assess the dynamic mechanical behaviour of an epoxy bi-component adhesive for structural bonding. In particular, the study has been focussed on the influence of the strain-rate on the tensile and compressive strength of specimens made of adhesive. The experimental tests have been performed with a hydraulic universal testing machine and a tensile-compression Hopkinson bar. The results of the tests show that the adhesive strength increases substantially by increasing the strain-rate. The Cowper-Symonds and Johnson-Cook models of strain-rate dependence have been used to fit the experimental data with unsatisfactory results, thus also a poly-linear fit has been adopted.