Abstract:
Cortical bone is a visco-elastic material which implies that strain rate will affect its response. Although the Split-Hopkinson Pressure Bar is an accepted technique
for determining the dynamic compressive properties of cortical bone it has been shown that the strain rate of compression does not remain constant throughout
the duration of a classical experiment with a uniform striker. This raises concerns as to the measurement of smeared responses. This paper presents a shaped
striker technique whereby the incident pulse can be shaped to attain a constant strain rate experiment for bovine bone. Shaped strikers offer benefits such as reusability
and increased test repeatability. A comparison of the stress–strain–strain rate responses attained through classical and constant strain rate experiments
shows that the shape of the stress–strain curves from conventional experiments is adversely affected in the portion where the strain rate varies. The dynamic
response corridors for the two tests are similar, however the ultimate properties are affected. It is concluded that the strain rate history should be presented with
dynamic stress–strain responses since the instantaneous strain rate is a likely contributor to potential constitutive models.
