Page 117 - Template Tesis UTM v2.0

incident bar and a transmitter bar which maintain the elasticity during the test as shown

in Figure 3.11. A drastic impedance mismatch between the specimen and the bar can
be controlled by using a high strength material, which resulted in the optimisation of

the transmitted strain signal with very low S/N ratio [136]. For this testing, a high
3
3
strength steel bar was used with the density of 7.85× 10 kg/m , the elastic modulus
of 200 GPa and the Poisson ratio of 0.3, respectively. The striker's diameter was 14.5
mm while the diameters of the incident and transmitted bars were both 16.0 mm.

During specimens’ preparation, the recommended slenderness ratio (height: diameter)

of 0.5 was followed in order to minimise the inertia effect, as suggested by previous
literature [113–115, 124]. The summary of the specimens’ size used in SHPB test is

tabulated in Table 3.4. As a precautionary step, wax/lubricant was applied at both ends

of the specimen’s interface to minimise friction and shear effects.

Figure 3.10 SHPB equipment at USTC, China

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