Lower Extremity Response to Blast Loading: A Computational Study

Computational assessment of leg response to extreme loadings using a detailed finite element model

This study focuses on evaluating the response of the Total Human Model for Safety™ lower extremity finite element model under blast loading. Biofidelity of the lower extremity model was evaluated against experiments with impact loading equivalent to underbody blast. The model response was found to match well with the experimental data for the average impactor speeds of 7 and 9.3 m/s resulting in an overall correlation and analysis rating of 0.86 and 0.82, respectively. The model response was then used to investigate response for antipersonnel mine explosion where the numerical setup consists of a charge mass of 40 g trinitrotoluene placed at a depth of 50 mm below the heel. The explosion was modeled using Multi Material-Arbitrary Lagrangian Eulerian method. The model was subjected to the graded input in terms of variation in standoff distance and mass of explosive to investigate the sensitivity of the model. The model found sensitive to the threat definition and predicted an increase of 110% in peak fluid-structure interaction force with 20% reduction in its time to peak and 29% increase in peak calcaneus axial force with a reduction of 33% in its time to peak when explosive mass varied from 40 g to 100 g. The location of the explosive below the foot was discovered to have significant effect on the injury pattern in near-field explosion. A comparative study suggested that the model predicted similar response and damage pattern compared to experimental data.