Application of a Dynamic Constitutive Law to Multilayer Metallic Sandwich Panels Subject to Impulsive Loads

The present paper describes an investigation that implements and assesses a dynamic continuum constitutive law for all-metallic sandwich panels. It also demonstrates its application to multilayer panels subject to water blast. Finite element calculations of unit cells are used to calibrate the model, especially the hardening curves at different strain rates. Once calibrated, the law is assessed by comparison with two sets of experiments. The dynamic response of panels impacted by Al foam projectiles at impulses comparable to those expected in water blast. The response of a multilayer core to an impulse caused by an explosion occurring in a cylindrical water column. The comparisons reveal that the overall deformation, average core strain, peak transmitted pressure, and velocities of the front and back faces are adequately predicted, inclusive of fluid/structure interactions. The inherent limitations of the approach are the underprediction of the plastic strains in the faces and incomplete assessment of stress oscillations beyond the peak. The former deficiency would pertain for any continuum representation for the core and would lead to problems in the prediction of face tearing. The latter may adversely affect the predictions of the impulse.