Verification and validation for a penetration model using a deterministic and probabilistic design tool

The Los Alamos National Laboratory Dynamic Experimentation (DynEx) program is the designing and validating steel blast containment vessels using limited experiments coupled with computational models. Through a need to design portions of the vessel to protect against breeches by projectiles, an analytical model was developed along the lines of the Walker–Anderson penetration model to predict the penetration depth of a projectile in a two- and three-layer target. The three-layer target consists of boron carbide ceramic (B4C), beryllium (Be), and aluminum. The two-layer target removes the Be. This model was integrated in the NESSUS ® probabilistic analysis program to provide a deterministic and probabilistic design tool. Through a verification and validation approach, the model predictions are compared to the experimental results for both target configurations. The probabilistic analysis or uncertainty quantification is an essential part of verification and validation (V&V) and is used to provide confidence in model predictions. Overall, the V&V procedure indicates that the model predicts the two-layer target results well and is biased conservatively. The three-layer target provides reasonable predictions for thinner ceramic layers. The probabilistic results provide additional insight into the model and experimental results comparison over a deterministic analysis alone. The results show that there may be incomplete physics in the modeling of Be and thicker B4C layers. The probabilistic sensitivity factors show that the projectile density, velocity and strength, and Be strength are important variables. This information provides insight into approaches to improve the model predictions and establishes validity for use of the current model for specific configuration ranges.