Abstract
The behaviour of stepped bars of different materials when impacted longitudinally by mild sphere of different radii was investigated. The passage (or propagation) of the longitudinal stress wave, created from the impact, from one end to another was recorded by strain gauges positioned at various stations along each bar. Different bar combinations with Lagrangian (material) and Eulerian (geometrical) discontinuities were investigated both experimentally and theoretically. Space - time diagrams which demonstrate the stress wave traversals across the discontinuity were constructed. The theoretical analysis of stress wave propagation in solids using the well-established Rayleigh acoustic equations assuming plane sections remain plane, was discussed, and the results were compared well with the experiments.
It was noted that a pulse travelling along a bar with a discontinuity, either in cross sectional area or material difference, will be subjected to amplification or attenuation as it passed through this discontinuity. The amount of change in amplitude was governed by the impedance ratio of the input to output bars. However, the reflected part of the pulse from the discontinuity was always attenuated, with the pulse sign governed by the impedance ratio. (C) 2022 Jordan Journal of Mechanical and Industrial Engineering. All rights reserved