Development of a Dynamic Nonlinear Finite Element Model of the Large Omnidirectional Child Crash Test Dummy

Abstract

<div class="section abstract"><div class="htmlview paragraph">The Large Omnidirectional Child (LODC) developed by the National Highway Traffic Safety Administration (NHTSA) has an improved biofidelity over the currently available Hybrid III 10-year-old (HIII-10C) Anthropomorphic Test Device (ATD). The LODC design incorporates enhancements to many body region subassemblies, including a redesigned HIII-10C head with pediatric mass properties, and the neck, which produces head lag with Z-axis rotation at the atlanto-occipital joint, replicating the observations made from human specimens. The LODC also features a flexible thoracic spine, a multi-point thoracic deflection measurement system, skeletal anthropometry that simulates a child's sitting posture, and an abdomen that can measure belt loading directly. This study presents the development and validation of a dynamic nonlinear finite element model of the complete LODC dummy. Based on the three-dimensional CAD model, Hypermesh was used to generate a mesh of the finite element (FE) LODC model. LS-PrePost was used to specify the material parameters, contact definitions, and initial conditions and then converted to LS-DYNA solver input format. A detailed description of the assemblies of the LODC dummy and their finite element representation is given. Component-level qualification test procedures were simulated using the LODC FE model, replicating the experimental test setups and boundary conditions for the head, neck, thorax, abdomen, and spine. Each component test provides a physical response that is used to calibrate the model's strain-rate-dependent viscoelastic material properties and other characteristics using an inverse method that minimizes the divergence between measured and predicted data. CORrelation and Analysis (CORA) ratings are provided between the simulation and experimental curves. Finally, a system-level sled test was modeled with the dummy upright on a sled bench for validation.</div></div>