Collaborating Laboratories
Time:2021.12.13    Hits:

The ELSA HopLab is a specialised laboratory (based on Hopkinson bar techniques) for the study of the behaviour of materials and structural components to very fast dynamic loads, such as those due to blast and impact, where knowledge of the material behaviour under high strain-rates is necessary. The laboratory has unique features with respect to the magnitude of the applied forces and the large size of the specimens to be tested.

The facility is operated by highly experienced scientific and technical staff and is supported by specialists in numerical simulation (see EUROPLEXUS).

The services offered by ELSA HopLab enable scientists to carry out high-quality research through unique experimental facilities for the characterisation of brittle or ductile materials and components at dynamic strain-rates and at high/low temperatures.

Large Hopkinson bar for ductile materials

This is the world’s largest Hopkinson Bar extending for a length of more than 200 meters. Thus, large material samples or structural components and sub-assemblies can be accurately tested under the required dynamic conditions. It features:

  • Bars of 72 mm diameter made of MSK steel
  • Maximum generated pulse: 1 MN force amplitude, 40 ms duration, 15m/s induced impact speed
  • Semiconductor strain-gages for increased sensitivity
  • Pulse generation using the pre-tensioned bar method and explosive bolt release
  • Ideal for tension tests; compression tests performed employing an ‘inversion frame’ developed according to specimen size and shape
  • Capability: maximum 2 tests / day

Medium-size Hopkinson bar for brittle materials

Modified Hopkinson bar designed for the compressive and tensile characterisation of brittle materials using large size specimens (concrete, glass, mortar, geo-materials etc.). It features:

  • Aluminium or steel bars of 100 mm diameter and 2.7 m length
  • Maximum generated pulse: 2 MN amplitude and about 0.8 ms duration
  • Semiconductor strain-gages for increased sensitivity
  • Pulse generation using the impactor bar
  • Capability: Maximum 4 tests / day

Additional equipment

Smaller Hopkinson bars of various bar diameters and lengths are also available for the testing of small material specimens under different dynamic loading types:

  • Apparatus for compressive testing of soft cellular materials
  • Apparatus for compressive testing of high-strength, brittle materials
  • Apparatus for tensile/compressive testing of metals
  • Capability: Maximum 5 tests / day

The ELSA HopLab is equipped with high-speed digital cameras (up to 50000 fps) and it has expertise for installing strain-gages and other sensors.

Please refer to the following website for more information: