Finite Element Model of the THOR-NT Dummy under Vertical Impact Loading for Aerospace Injury Prediction: Model Evaluation and Sensitivity Analysis

Abstract

Anthropometric test devices, commonly referred to as crash test dummies, are effective tools used to conduct aerospace safety evaluations. In this study, the latest finite element (FE) model of the Test Device for Human Occupant Restraint (THOR) dummy was simulated under vertical impact conditions based on data recorded in a series of drop tests conducted at the NASA Langley Research Center. The purpose of this study was threefold. The first was to improve and then evaluate this FE model for use in a vertical loading environment through kinematic and kinetic response comparisons. The second was to evaluate dummy injury criteria under variable impact conditions. The last was to determine the response sensitivity of the FE model with respect to its preimpact postural position. Results demonstrate that the updated FE model performs well under vertical loading and predicts injury criteria values close to those recorded in testing. In the postural sensitivity study, the head injury criteria response and peak lumbar load show to be primarily sensitive to the preimpact head angle and thorax angle, respectively. The promising results shown by the dummy model recommends its use in impact simulations with vertical deceleration pulses close to those used in this study. In addition, it is believed that assigning accurate viscoelastic material properties to the deformable parts of the model may further increase the model fidelity for a larger range of impacts.