ROLLA, Mo. – A University of Missouri-Rolla professor’s research in mathematical modeling may lead to better anti-gravity suits for fighter pilots.
Dr. Xavier Jayaseela Avula, professor emeritus of mechanical and aerospace engineering and engineering mechanics at the UMR, has developed the mathematical model that describes how the suits actually work.
"I have shown mathematically and computationally that the blood accumulated in the lower part of the body during high-performance aircraft maneuvers can be lifted by external submergence," says Avula.
While the principle of buoyancy has been around for nearly 2,000 years, using it to negate the effects of high acceleration on the human body is a relatively new use. Until now, researchers have not been able to mathematically show these effects, says Avula.
In recent years, advances in materials science and power plant technology have contributed to the concept of aircraft flying at fantastic speeds. The design of military aircraft, however, has been stifled by pilots’ physical limitations.
According to Avula, the high accelerations and tight turning capabilities of modern fighter aircraft exert forces of up to 12 times greater than normal gravity. Pilots cannot tolerate this unaided.
These high gravity forces push the pilot’s blood supply down the body to the legs and feet, drawing it away from the brain. This results in impaired vision, lightheadedness and even loss of consciousness, says Avula.
Body suits lined with liquid bags, called "liquid muscles," ward off the effects that high acceleration has on the body. These liquid-filled anti-gravity suits simulate the body’s natural buoyancy when submerged in water. The suits respond in a self-regulating fashion to the change in pressure and applies external pressure to the lower extremities of the body, shifting the blood back to the upper regions, maintaining much needed circulation in the brain.
Using the nonlinear theory of large deformations, Avula developed the mathematical model that describes how the liquid filled suits work and identified the design parameters for the suits.
"This mathematical model will enable the (anti-gravity pressure suit manufacturing) company to utilize these with the necessary design parameters for the improvement of the suit," says Avula. "The problem with the current suit is that the liquid in it does not make full contact with the skin, which decreases its effectiveness and does not take into consideration other creative configurations that enhance its performance. This mathematical theory will help optimize the suit’s design and increase its effectiveness."
Before liquid-filled gravity suits were developed, fighter pilots used air-filled pressure suits equipped with valves and regulators to tolerate the effects of high acceleration. The suits were hot, heavy, uncomfortable and only partially effective, says Avula.
Avula presented his findings at a Safety and Flight Equipment (SAFE Europe) conference in Sweden last March and in the U.S. Air Force sponsored panel on foreign comparative testing at the 2002 SAFE conference in Jacksonville, Fla., on Oct. 2.