Split Hopkinson Tensile Bar

Split Hopkinson Tensile Bar (SHTB) setups are used to study the constitutive, damage and fracture behaviour of materials at strain rates from 100 s^-1 up to 10 000 s^-1. The concept of the Split Hopkinson Tensile Bar setup involves a short test sample sandwiched between two long bars: an input bar and an output bar. A tube-like impactor is put around the input bar, and accelerated towards an anvil at the outer end of the input bar. Thus, a so-called incident tensile wave is generated and propagates along the input bar towards the specimen. The velocity of the impactor determines the strain rate in the sample. The incident wave interacts with the specimen, generating a reflected wave and a transmitted wave. The incident, reflected and transmitted waves are measured using strain gauges at well-chosen locations on the Hopkinson bars. From these waves, the total force and elongation history of the specimen can be determined based on the principle of elastic wave propagation in slender bars.

Technical Specifications

• Total setup length = 12 meter, enabling loading times up to 1.2 ms
• Strain gauge measurements on Hopkinson bars (not on specimen)
• Sample in dynamic equilibrium during high strain rate deformation
• Strain rates from 100 s^-1 up to 2 000 s^-1 and strains exceeding 100% can be achieved
• Local strain measurements using high speed camera imaging and Digital Image Correlation
• Dynamic uniaxial tensile testing on advanced high strength steels, pipeline steels, stainless steels, aluminium alloys, titanium, fibre reinforced plastics, steel cord and wire, Kevlar fibres, ...