Development and Full Body Validation of a 5 th Percentile Female Finite Element Model Matthew L. Davis 1,2 , Bharath Koya 1,2 , Jeremy M. Schap 1,2 , F. Scott Gayzik 1,2 1. Wake Forest School of Medicine 2. Virginia Tech-Wake Forest Center for Injury Biomechanics Introduction: Computational human body modeling has become an important tool for the development of safety devices in the automotive and defense industries. Such models are often developed to represent a 50th percentile male (M50). However, in order to address the effects of size and sex-related geometrical changes, there is interest in developing models of other cohorts. This study focuses on the female in the 5th percentile of height and weight (F05). As part of the Global Human Body Models Consortium (GHBMC) project, comprehensive medical image and anthropometrical data of the F05 were acquired for the specific purpose of finite element model (FEM) development [1]. The objective of this study is to apply these data to generate and validate a detailed FEM of the F05 in a seated posture representing a vehicle occupant. Materials and Methods: The F05 occupant (F05-O) model geometry was developed using an image dataset consisting of CT, MRI and upright MRI images of one representative small female subject in the seated, standing, and supine postures. The CAD geometries assembled from the medical images were utilized for mesh development of the F05-O FEM. Structured hexahedral mesh was used in the majority of the body with the exception of the abdomen. In general, material definitions were applied based on GHBMC average male model. The model was compared to experimental data in 10 validation cases ranging from localized rigid hub impacts to full body sled cases. In order to make direct comparisons to experimental data, which represent the mass of an average male, the model was compared to experimental corridors using two methods: 1) post-hoc scaling the outputs from the baseline F05-O model and 2) geometrically morphing the model to the body habitus of the average male to allow direct comparisons. This second step required running the morphed full body model in all cases for a total of 20 simulations. Model outputs were objectively evaluated using ISO/TS 18571. Results: The F05-O model consists of 981 parts, 2.6 million elements, and 1.4 million nodes (Figure 1) [1]. Thresholds were placed on several element quality criteria: Jacobian (>0.3 for solid elements and >0.4 for shells), tet-collapse (>0.2 for all elements), zero intersections, and a minimum time step of 0.1 μs. Contacts were minimized via node-to-node connections and element property assignment based on the CAD data. Overall, geometrically morphing the model was found to more closely match the target data with an average ISO score for the rigid impacts of 0.76 compared to 0.67 for the scaled responses. Based on these data, the morphed model was then used for model validation in the vehicle sled cases and attained an average weighted score of 0.69. Figure 1. Images of the assembled F05 finite element model Translational Impact: This study describes the application of a multi-modality image dataset to the development of an anatomically representative small female FEM. The F05-O is the third in the GHBMC family of detailed occupant models (M50, M95) [2, 3]. As such, the F05-O will not only be used for predicting injury risk for small women, but will also provide a tool for evaluating differences in biomechanical response for occupants of varying body habitus. Furthermore, quantitative comparison between various approaches of model output scaling will provide needed insight, particularly as human body modeling is extended to body sizes beyond the M50. Disclosure Statement: Dr. Gayzik is a Member of Elemance, LLC, which provides academic and commercial licenses of the GHBMC-owned human body computer models. Acknowledgements: Funding for this project was provided by the Global Human Body Models Consortium, LLC through Project Number WFU-005. References: [1] Davis et al. Stapp Car Crash J. 60(2016) 509-44. [2] Gayzik et al. ABME 39(2011), 2568. [3] Vavalle et al. Stapp Car Crash J. 58(2014) 361.