RT&L FOCUS AREA(S): General Warfighting Requirements (GWR) TECHNOLOGY AREA(S): Bio Medical OBJECTIVE: The objective of this SBIR is to develop a computational model of the human lung as it responds to underwater blast insult in order to predict injury in explosive ordnance disposal (EOD) personnel exposed to underwater explosion (UNDEX). To meet this objective, a finite element model (FEM) that accepts UNDEX metrics and outputs lung physiological response and/or injury from the blast insult will be developed. Development of the underwater blast lung model will improve existing injury predictions and provide actionable injury assessment to mission planners as they evaluate operational risk management. DESCRIPTION: FEM is a valuable tool in a number of industries (e.g. automobile) for predicting human injury to a variety of traumas. The Department of Defense (DoD) has sponsored the development of computational models that predict how the human body will respond to in-air blast insult. The focus of this SBIR is to identify a software modeling approach that can characterize the physiological response of human lungs to underwater blast insult. The model must be able to compensate for the lungs being under hydrostatic pressure (up to 200 ft seawater) for divers operating on scuba equipment. In addition, the interactions between the blast wave and lung response with the surrounding bone, muscle, and tissue in and around the thoracic cavity needs to be incorporated into the model. As divers may be using different gas mixes other than air (e.g. heliox, tri-mix), incorporation of this variable would be highly valuable, but is not mandatory. This model will provide predictive physiological responses to underwater blast to improve risk modeling for establishing safe standoff distances for EOD divers working around explosives. The software models developed by this SBIR can be marketed for use by the DoD and other communities, who have divers working with explosives or other impulsive noise sources (e.g. seismic airguns, pile driving, underwater construction tools). Early adopters of the software modeling products from this SBIR may include surface and undersea warfare operators and undersea construction and salvage crews. In addition, these models would also be valuable to environmental protection groups within the DoD as well as industry for use in predicting injury to marine mammals and other aquatic life. Companies have had success being able to commercialize high fidelity human anatomy models for the scientific community. PHASE I: In Phase I, researchers will identify the physical modelling requirements and physics that must be solved related to the properties of the model. Researchers will identify an appropriate code base that is suitable for solving the response physics. A simple model (e.g. lung-sized sphere) will be created that responds appropriately to the underwater blast physical properties. Model outputs shall be validated against theoretical predictions or experimental data. The physiological variables that will need to be incorporated into the model to transition from the simple spherical model to an anatomically correct version of the model shall be characterized. The performance and capabilities of the final model for Phase I will be demonstrated. Finally, researchers will identify the recommended approaches that will be used in Phase II. These approaches will be identified in consultation with the COR and subject matter experts. PHASE II: In Phase II, the model will be made more complex by transitioning to an anatomically-correct lung shape and incorporating specific tissue and material properties of the lungs and surrounding tissues. Specifically, an upper torso model shall be created that incorporates bone, soft tissue, lungs, and diaphragm at sizes accurate to a 50th percentile male. As with Phase I, this model should respond appropriately to the UNDEX physical properties. The model outputs shall be compared to experimental data from physical models to be provided by the COR. Each of the tissue layers should show a response to the underwater blast insult. However, the interactions between tissues, being much more complex can be planned for Phase III. The Phase II model and data will be demonstrated and delivered to the COR for further evaluation and analysis. PHASE III DUAL USE APPLICATIONS: In Phase III, a complete underwater blast lung and thorax computational model will be developed. This will include high fidelity anatomical structures as well as the interactions between all structures (e.g. lungs interaction with rib cage; diaphragm interaction with lungs). The model should be able to respond to a variety of UNDEX scenarios including explosives with different charge weight, explosive type, and location of explosive relative to lungs in water column. Also, the model should incorporate lungs at different depths and orientations in water column, as well as with the lungs at different inflation volumes (e.g. due to inhalation/exhalation). The Completed model and data will be delivered to the sponsor for further evaluation and analysis. Additional Phase III follow-on work may include extending the modeling techniques to marine mammals or diving birds. This model will provide immediate value for DoD entities such as Naval Surface Warfare Center Indian Head and the Naval Submarine Medical Research Laboratory, who support the development of safe standoff requirements for divers operating around underwater explosives. The Army Simulation and Training Technology Center (STTC) could potentially want to integrate this model into their simulation platforms. Additional non-DoD customers that this model could be marketed to would be industries that employ divers for explosive work, construction, and other infrastructures in which divers are subjected to high energy underwater sources such as explosives, pile driving, or seismics. Numerous companies have developed high fidelity human models that are available for commercial use (e.g. Zygote, Biodigital, 3D4Medical). There is a strong potential of interest from academia and scientific institutes for evaluating effects on animal models (i.e. diving birds, marine mammals). Joint Program Committee (JPC)-1 has also expressed an interest in tracking the model's development towards a completed product to evaluate its potential as a training component [5]. REFERENCES: Richmond, D. R., Yelverton, J. T., & Fletcher, E. R. (1973). Far-field Underwater-Blast Injuries Produced by Small Charges. Lovelace Foundation for Medical Education and Research, Cudahy, E. A. & Parvin, S. J. (2001). The Effects of Underwater Blast on Divers. Naval Submarine Medical Research Laboratory, Report 1218, Groton, CT, USA. Lance RM, Capehart B, Kadro O, & Bass CR (2015) Human Injury Criteria for Underwater Blasts. PLoS ONE 10(11): e0143485. Chanda, A., & Callaway, C. (2018). Computational modeling of blast induced whole-body injury: A review. Journal of Medical Engineering & Technology, 42(2), 88-104. Personal communication with Joint Program Committee (JPC) -1, 2 October 2020.
