Calibration of empirical penetration models using large deformation explicit finite element simulations of rapid penetration in clay

Numerous former military sites worldwide require environmental cleanup from buried unexploded ordnance (UxO) that pose hazards such as leaching toxic chemicals and explosion risks. However, selecting the appropriate mitigation technology relies on prior knowledge of UxO depth of burial (DoB) at specific sites. This study utilizes numerical simulations, employing large deformation explicit finite element (LDEFE) analysis and the Coupled Eulerian-Lagrangian (CEL) approach, to model the penetration of ordnances into clay targets. A modified Tresca constitutive model is implemented in ABAQUS software to capture key features of clay behavior under high strain rate (HSR) loading. The role of various parameters on DoB is investigated, including undrained shear strength, stiffness, and density of the soil. The findings highlight the paramount importance of undrained shear strength in clayey soil penetrability, in addition to the role of soil stiffness, and density. The simulations were employed to calibrate model parameters for Young's empirical penetration model, as well as the Poncelet phenomenological penetration model, demonstrating the efficacy of the numerical simulations in extrapolating its findings within the relevant parameter space. In particular, the calibrated parameters of Young's and Poncelet's models can be identified as a direct function of the various discussed soil properties, which was previously unavailable.