The I-PREDICT 50th Percentile Male Finite Element Model: Development and Validation of the Torso.

Behind Armor Blunt Trauma (BABT) is a phenomenon that occurs when energy is transferred from Personal Protective Equipment (PPE) to the human body and can range from minor to fatal injuries. The current standard to evaluate PPE uses Roma Plastilina No. 1 clay and has a poor correlation to human injuries. To provide a more suitable human surrogate for evaluating risk of injury and functional incapacitation due to BABT, the Incapacitation Prediction for Readiness in Expeditionary Domains: an Integrated Computational Tool (I-PREDICT) has developed a 50th percentile male human body model (HBM) to better understand injury mechanisms in the BABT environment. The model was developed using a hierarchical validation approach including component, regional, and whole torso level tests. Material properties were sourced from literature and I-PREDICT experimental test data, and the model was simulated in 25 different validation cases ranging from component level quasi-static tests to high-rate BABT impacts. The model was stable in all 25 simulations. CORrelation and Analysis (CORA) and BioRank were used to objectively quantify the model response. The average CORA and BioRank across all validation cases were 0.78 ± 0.18 and 0.68 ± 0.27, respectively, indicating 'good' agreement by CORA standards and 'excellent' by BioRank standards. When compared to high-rate BABT experimental impacts on post-mortem human subjects, the I-PREDICT HBM accurately predicted rib fracture probability. The ultimate goal of the I-PREDICT model is to predict injury and functional incapacitation for various in theater military applications. This study highlights the development and validation of the I-PREDICT torso and highlights initial BABT use cases.