Response of split Hopkinson bar apparatus signal to end-surface damage, numerical and experimental studies

Abstract

A Split Hopkinson bar apparatus is a widely used method to obtain material properties at high strain rates. These properties are essential in the development of new materials as well as their associated constitutive models. During routine tests, the surfaces of the bars at the specimen/bars interface were damaged. To check if the damage influenced the signal response, control tests were done using the well characterized Al 6061-T6. Results showed that artefacts were added to the signal. This paper presents the experimental and numerical approaches developed to understand the effects of surface damage. The approach used consists of introducing series of known gaps between input and output bar to simulate a variation of surface damage. The numerical simulations, performed using a hydrocode, were done to confirm that signal response could not be associated with other several types of error in the system.