Effect of Radial Confinement on Wave Propagation and Vibrational Response in Bars

It is currently beyond the state-of-the art to accurately predict the instantaneous dynamic response of a structure with rapidly changing boundary conditions. In order to establish a basic understanding of changing boundary conditions, we examine the wave propagation through a bar subject to mechanical confinement. The Air Force Research Laboratory has conducted several experiments investigating the effect of non-traditional boundary conditions, such as mid-structure confinement, on the local and global dynamic response of rods using a modified Hopkinson Bar configuration with radial clamping. We have shown that the wave velocity in the mechanically clamped area is significantly lower than that in a stress free bar. This paper presents the experimental results and analytical modeling of the effect of radial confinement on dynamic response in bars.