Pre-Compression Kolsky Bar Tension Bar System for Brittle Material Testing

The development and implementation of a new tension Kolsky bar system for testing brittle materials is proposed in this effort.  Due to the relatively low failure stress and strain of brittle materials tested in tension, it is difficult for researchers to obtain axial stress equilibrium in the sample using a traditional Kolsky tension bar system.  The lack of axial stress equilibrium during the dynamic loading phase of the experiment results in a non-uniaxial stress state and inconsistently measured material properties.  By pre-compression loading of the test specimen in this new apparatus, the brittle material can reach dynamic axial stress equilibrium early into the tensile load cycle and well before tensile failure.  Additionally, by reaching stress equilibrium in the sample earlier during the tensile cycle, higher strain rate testing can be achieved on these brittle materials.  In this effort, Dynamic Systems and Research (DSR) teamed with Professor Xu Nie from Southern Methodist University (SMU) will develop, manufacture, and support initial check-out testing of a novel pre-compression tension Kolsky bar system for the US Army.