Cylinder Impact Deformed Lengths and Time Series for Strength Model Calibration

Assuming constant flow stress, Taylor and Hawkyard formulated simple mathematical descriptions of plastic cylinder deformations by invoking

conservation of momentum and energy, respectively. Over a range of flow stresses, these two conserved quantities give consistent answers for the final

deformed cylinder length. Based on this result, we recently created an efficient solver that estimates an average flow stress, true strain, strain rate and

temperature based on the initial and final lengths of a deformed cylinder. This allows us to include the final length of a deformed cylinder in a material

strength model calibration without the computational overhead of running a hydrocode. We will present the results of using this technique to add cylinder

impact data to the calibration of a Preston-Tonks-Wallace strength model based on quasistatic and split Hopkinson pressure bar data. Additionally, we

will study the potential for extension of this method to constrain the strain and strain rate dependence of the flow stress using high speed imaging data.

These techniques add value to cylinder impact data, which is traditionally viewed as validation data.