Development of New Method for Direct Measurement of High Strain Rate Testing Parameters

High strain rate testing and dynamic characterization of materials have been always serious challenges. Traditional Split Hopkinson Pressure Bar (SHPB) is being used for this purpose for the last 100 years. Traditional SHPB concept relays completely on the one dimensional stress wave propagation theory that adopts several assumptions. Besides, this method is subjected to some limitations of specimen dimensions, specimen material type, bars material, pulse shaping and others. The new developed direct measurement SHPB utilizes two force sensors to measure forces on both sides of the tested specimen thereby the stress on the specimen. Also, it utilizes two laser displacement sensors to measure the displacement on both sides of the specimen thereby measure the strain and the strain rate. This system measures the stress, the strain and the strain rate simultaneously all through the test period. The new developed method opens the door for great developments in the field of dynamic testing and characterization of all types of materials. It is a non-assumptions method independent of specimen material or dimensions.