Biomechanics

The Biomechanics group is utilizing advanced computational, as well as unique experimental techniques and facilities to address a number of biomechanics-related problems. Advanced Probabilistic Mechanics and Reliability methods are being employed to address how the inherent variability and uncertainty associated with biological systems affects predictions of system performance and functionality. In one application, the probability of injury to the cervical spine (neck) of naval aviators due to high acceleration maneuvers is being investigated.

SwRI engineers are working to quantify the increase (or decrease) in risk of injury between male and female pilots. Because ejection systems are designed for the average male aviator, it is possible that females could be more prone to injury during ejection because of their smaller physical size. Since many injuries localize in the cervical (neck) spine region, SwRI has begun working to develop a numerical model from CT scan "slices" from a representative set of males and females. A three-dimensional image constructed from a set of slices is shown in the figure. Uncertainties, whether due to the systematic size difference between males and females, or due to the inherent randomness in configuration of the spinal components or physical properties, will be simulated by analyzing the model using SwRI-developed advanced probabilistic analysis techniques. With the difference in risk of injury between male and female pilots in hand, the Naval Air Warfare Center (NAWC) will be better equipped to recommend changes in ejection systems in order to reduce the risk to female aviators.

Advanced reliability methods are also being applied to improve the design and long term functionality of orthopaedic implants by incorporating reliability measures in an optional design framework. Using this methodology, the probability of implant failure is computed and used as a design objective to minimize or as a design constraint to meet while improving the overall design of the implant.
 

Advanced micromechanical characterization and analysis techniques are being utilized to understand the micromechanical behavior of bone. By combining stereoimaging with optical and atomic force microscopy, Institute engineers are gaining new insights into damage formation in cortical bone as well as the mechanisms underlying bone remodeling and adaptation. 

For further information, contact: Dan Nicolella, Ph.D., Principal Engineer.

Materials Development Section Materials Engineering Department
Mechanical Engineering Division
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November 18, 2009