The direct impact method for studying dynamic behavior of viscoplastic materials

Abstract

Equipping mathematical models of deformation of viscoplastic materials with the necessary parameters and constants requires comprehensive experimental data meeting the requirements of the problem being analyzed. For problems of evaluating strength of dynamically loaded structures, it is important to account for the strain rate effect on the yield surface radius. Experimental schemes for studying such an effect can be constructed based on the measuring rod technique. Such methods include, for instance, the well-known Kolsky method. The methodological limitations of the above experimental scheme necessitated the development of its alternative versions to widen the range of realized strain rates studied. The present paper gives the description and the results of numerical analysis of an experimental method implementing the socalled direct impact scheme that is also constructed based on the measuring bar technique. The method is used for determining deformation diagrams of viscoplastic structural materials loaded in high-rate compression with strain rates higher than those in the traditional Kolsky method. Using the Kolsky method and the direct impact method, deformation diagrams of copper S101 and aluminum alloy D16Т in the strain rate range of 1000 to 10000 s-1 have been obtained.