Methodologies for Cost-Effective Measurement of Dynamic Material Properties or Characterization of Materials under Dynamic Loads

Explosions and high-velocity impacts can create strain rates on the order of 105 to 107 s-1. To simulate these events, first-principles codes require material models that are valid at these loading rates. Currently, the amount of test data, material models and material constants for this strain rate range is extremely limited, and an innovative and cost-effective laboratory test procedure is needed. To address this need, Protection Engineering Consultants (PEC) teamed with Southwest Research Institute (SwRI) to develop a novel high-rate loading procedure that employs lasers to generate short duration shock waves within solid materials. This approach was used to measure the shock velocity, particle velocity, Hugoniot Elastic Limit (HEL), and strain rate, at rates exceeding 107 s-1 in aluminum. Multiple tests were performed in an hour, using the same sample and test setup; the cost savings compared to traditional ballistics-type testing are huge. PEC developed signal processing and data analysis techniques to identify the material properties and then to evaluate constitutive models and material constants in first principle codes. In Phase II, a number of improvements will be made to the system, including a more powerful laser, additional PDV instrumentation, and automated signal processing followed by material constant determination. Approved for Public Release | 18-MDA-9522 (23 Feb 18)