Thermomechanical behavior of adhesively bonded joints under out-of-plane dynamic compression loading at high strain rate

In this study, a new experimental approach in which the deformation, the damage kinetic, and the temperature are measured simultaneously during a high strain rate on adhesively bonded composite joints. Especially, our goal is to quantify the amount heat dissipation during impact and to identify the mechanisms that induce this dissipation. Out of plane dynamic compression tests were conducted on assembled specimens over a range of strain rate from 372 s(-1) to 1030 s(-1) using the Split hopkinson Pressure Bars technique. The specimen surface temperatures were monitored using an infrared camera. The increase in the strain rate has a dramatic effect on the stress-strain behavior producing a significant heat dissipation in the material. The infrared monitoring provides the spatial distribution of temperature that increase near the adhesive/adherent interfaces of the specimen. The observed temperature increase profiles clearly show that the stress concentration appears in the adhesive area and provide valuable information regarding the damage mechanisms and their role in the heat dissipation during dynamic loading conditions. The dependence of these results on strain rate indicates that there exists a correlation between the thermo-mechanical behavior and the strain rate effect, which might be useful when developping damage models taking into account the energy balance for adhesively bonded joints under impact loading conditions.