Discussion On Hopkinson Bar Test Method

The Hopkinson bar is an innovative technology that was developed in recent 50 years. It is the most commonly method for determining material properties at high rates of strain. Some regular rules about dynamic deformation and fracture of material were studied. The main work results are as following:(1) Stress uniformization process of dynamic compression test specimen was studied. Through analyzing stress uniformization process of series size test specimens, test specimen size scope with low unevenness was obtained.(2) Inertia effect of series size dynamic compression test specimens were studied.(3) The new method of determining dynamic yield strength was established on the basis of analyzing stress uniformization process and inertia effect of series size test specimens.(4) On the basis of analyzing stress uniformization process and inertia effect of series size test specimens, test specimen size scope with high test precision was obtained.(5) The behavior of dynamic fracture test which using Hopkinson pressure bar was imitated by Finite-Element Method. The result showed that: when Charpy impact specimen was loaded by Hopkinson pressure bar, 'Loss of Contact'(LOC) was observed.