Publications
Split Hopkinson bar experiments of preloaded interfaces
Preloads are routinely applied to stiffen structural members in many applications. However, the preloaded structural members have been observed to lose a significant portion of the imposed load due to internal relaxation mechanisms during impulsive impact events. This paper describes the design and initial experiments for a novel Hopkinson bar configuration designed to investigate the effect of preloads on the stress wave propagation across interfaces between the incident and transmission bars. Dynamic responses are measured by a variety of sensors, including accelerometers, strain gages, and a laser vibrometer. The transmissibility of a titanium incident bar is measured to establish the baseline frequency response between the input and the test interface. Wave transmission across an titanium-aluminum interface is also examined by analyzing the frequency response function, transmission efficiency, and transmissibility between the incident and transmitted waves. The presence of vacuum grease is shown to strongly influence the dynamic behavior of the system.