Split-Hopkinson pressure bar

Materials undergo high strain rates deformation in various applications, e.g. accidental events such as explosions and penetrations, and engineering applications such as crash worthiness of vehicles, bullet proof armors, impact resistant pressure vessel and shipping cask for transport of nuclear materials. In addition to this,forming processes like extrusion, rolling and high speed machining can also result in high strain rate deformation. For the optimal design and safety analysis of components seeing high strain rates of loading the constitutive behavior of materials at high strain rates is required. Dynamic testing of material is becoming more important due to the need for more optimized crashworthiness and impact analysis. Positive strain rate sensitivity, i.e. the strength increases with strain rate, offers a potential for improved energy absorption during a crash event. The load can be an instant load wave used for very high strain rate. The machine will also have the proper measurement systems to measure and record the important parameters, such as strain, displacement and load. The systems has been developed by Adavnce Instrument Inc. in recent years to meet the increasing demand for dynamic testing. Split-Hopkinson bar (SHB) works on the principle of one dimensional wave propagation. Its main components are a gas gun, a striker bar, an incident bar and a transmission bar . The striker bar sits in the barrel at the gas gun chamber. The incident bar, transmission bar and striker bar are all made of same material and same crosssection area. At all times during the test the striker, incident and transmission bar should remain elastic.