Development of a Split Hopkinson Pressure Bar Machine for High Strain Rate Testing of Bonded Joints

The design of adhesively bonded connections for structural applications has recently become a major field of research, with extensive applications in the automotive and aerospace industries. In these structures, bonded joints are often subjected to important static and dynamic loads, which require careful geometrical dimensioning and material selection. The performance analysis of adhesive joints under these conditions is often made with numerical modeling and supported by experimental studies that can correctly characterize their mechanical behavior. To obtain this characterization under impact conditions, it is critical to employ equipment suitable for impact testing of adhesives and adhesive joints. For this reason, an innovative Split Hopkinson Pressure Bar machine was designed. This machine includes a pneumatic actuator capable to operating up to 30 m/s in both directions, and an innovative lever-based braking system, capable of stopping the actuator for both tensile and compression tests. The tensile and compression pressure bar setups, as well as the machine support and its characteristics, are also described.