The test machine together with a high-rate synchronal data acquisition instrument provides a facility (Instron VHS 160/100-20) designed for tensile, impact and puncture testing of metals, plastics and composite materials, in particular, under a constant velocity profile accurately controlled. The hydraulic piston actuator is capable of constant speeds from 0.1 to 20 m/sec. The maximum load can be up to ±100kN. Environmental temperature can be in the range of -100° to +250°. Strain rate dependence of materials at medium/high strain rates may be revealed across such a wide range of velocities.
Fig.1 Overall View of Medium/High Strain Rate Test System
The displacement of piston actuator measured by a position transducer is sampled at high rate with the maximum sampling rate up to 60 M Samples/sec. The loading force is recorded synchronally by a dynamic load transducer to obtain load-displacement curves under different velocities. For a typical specimen with a testing gauge length of 5mm, the strain rates can vary from 100 to 102/sec, in part, filling the gap in strain rate between the quasi-static tests and Hopkinson bars.
The testing system serves as a potential tool for investigating the dynamic behavior of materials at medium/high strain rates encountered in real life such as machining, forging, punching, or crash analysis.
Fig.2 Tensile Test Set-up Details with Specimen Mounted