Split Hopkinson Pressure

To extend pulse calorimetry to selected mechanical properties, NIST has developed a new apparatus called the pulse-heated Kolsky bar, or split-Hopkinson pressure bar apparatus [127, 128]. The combination of the two techniques produces high-rate dynamic loading, while simultaneously pulse heating the specimen with electrical current. 

Dynamic mechanical experiments were completed with SHPB test device from China University of Mining and Technology (Beijing), The Split Hopkinson Pressure Bar (SHPB) is currently widely used to study dynamic strain rate. Using cp50 mm SHPB test device, dynamic mechanical properties of coal and limestone under different strain rates were analyzed and mechanical properties of coal and limestone were explained from the structure. 

The impact experiments of anthracite and limestone samples were conducted by using 4>50 mm split Hopkinson pressure bar (SHPB) experiment system, the dynamic mechanical properties of samples are analyzed under impact loading. Finally, the relationship between the dissipation energy and impact velocity is studied. The main conclusions are as follows. 

Dynamic Tensile Test of Coal, Shale and Sandstone Using Split Hopkinson Pressure Bar ... 

Frew, D. J., Forrestal, M. J., Chen, W. (2001). A split Hopkinson pressure bar technique to determine compressive stress-strain data for rock materials. Experimental Mechanics, 41, 40-46. doi 10.1007/BF02323102... 

Ross, C. A., Thompson, R Y., Tedesco, J. W. (1989). Split-Hopkinson Pressure-Bar Tests on Concrete and Mortar in Tension and Compression. Aci Materials Journal, 86,475-481. 

Gray GT (2000) Classic split-Hopkinson pressure bar technique. Mech Test Eval, ASM Handbook 8 462-476 Chen W, Zhang B, Forrestal MJ (1999) A split Hopkinson bar technique for low-impedance material. Exp... 

The version of the apparatus used nowadays was introduced by Kolsky (1963), who added a second bar, from which the name Split Hopkinson Pressure Bar comes from the specimen of material to be tested is inserted between the two bars, as shown schematically in O Fig. 21.5a. The projectile, usually fired by means of a pneumatic gun, impacts the first bar (incident bar), generating the incident pulse which, at the bar/specimen interface, is partially reflected and partially propagates in the specimen. From the specimen, the pulse is transmitted to the second bar (transmitter bar). The situation is described graphically by the so-called Lagrangian diagram presented in O Fig. 21.5b. A concrete example of Split Hopkinson pressure bar is shown inO Fig. 21.6. The pulses are measured by means of strain gages placed on both incident and transmitter bar thus, their time history can be stored by means of a transient recorder, usually a digital oscilloscope or an acquisition board. From such measurements the stress (a), strain (e), and strain rate (s) in the specimen can be obtained as... 

Split Hopkinson Pressure Bar (a) overall view (b) detail of firing system and first bar (Politecnico di Torino - Vercelli Lab]... 

Forrestal MJ, Wright TW, Chen W (2007) The effect of radial inertia on brittle samples during the split Hopkinson pressure bar test. Int J Imp Eng 34 405-411... 

Figure 6.17 Schematic of a split Hopkinson pressure bar apparatus.

Projectile impact tests and blast tests are more difficult to interpret than drop-weight or Split Hopkinson Pressure Bar tests in terms of specimen strength. For these tests, some arbitrary measure of damage may be necessary, but this again shows up the difficulties in comparing the results obtained from different test arrangements. 

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