Stress analyses play a critical role in understanding the structural performance and the mechanics of injury of biological systems. For more than two decades, researchers have endeavored to model the structural/dynamic behavior of the human body using increasingly complex and sophisticated computational modeling approaches such as finite element analysis techniques. The advantages of using finite element analysis are clear: complex geometry and boundary conditions can be modeled, heterogeneous and non-linear materials can be simulated, parametric studies isolating the effect of one or more variables can be performed, and delineating the stress distributions within the various components of the biological structure can be accomplished. This information may serve as a basis to evaluate the response of the biological structure to impact and long term exposure to high-g accelerations.
The broad goal of this program is to develop a probabilistic injury model of the human spine. Building on previous efforts, a high fidelity, kinematically and anatomically correct, three dimensional, non-linear finite element model will be developed. Furthermore, the model will be parametrically based so that gender differences can be readily assessed. This model will be used with sophisticated, efficient probabilistic computational mechanics methods to predict the risk of injury to naval aviators due to impact and long term exposure to high-g accelerations.
This project is in support of the Navy's interest in quantifying the risk of injury to military aviators. This interest arose for several reasons:
The likelihood of injury during high-speed ejection combined with the consequence of spinal injury warrants efforts to make cockpit systems safer.
The number of candidate female aviators entering the Navy is increasing and current escape systems are designed for males who on average are larger than females.
The effects of exposure to long-term high-g loads can result in chronic injuries.
Thus, the objective of this effort is to quantify probability of injury and the difference in risk of spine injury between male and female aviators using numerical simulation and first principle models. With the risk of injury quantified, design changes in ejection, seating, and helmet systems can be recommended to reduce the risk to military aviators.
Southwest Research Institute® (SwRI®), headquartered
in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied
engineering and physical sciences research and development organization with
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