[A simulation study on G protection using tilt-back seat].
A mathematical model of human cardiovascular system with cardiopulmonary interaction was developed basing on the previous works of Jaron, Bai jing, et al (1988, 1992). The model of pulmonary circulation was improved and intrathoracic pressure, intra-abdominal pressure and pulmonary alveolar pressure were introduced in the new model. Computer simulation experiments using this model for human relaxed tolerance to rapid onset (1 G/s), gradual onset (0.1 G/s), and high onset (5 G/s) G exposures, at seat back angles of 13 degrees, 30 degrees, 45 degrees, 55 degrees, 65 degrees, 75 degrees, and 85 degrees, were performed. The simulation results are consistent with the experimental data obtained from reported centrifuge experiments. The tolerance increase by tilt back seat may be attributed to the following three factors: (1) decrease of retinal-aorta hydrostatic distance; (2)decrease of venous pooling in the lower body; (3)decrease of G onset rate in Z axis.
Lu
H
H
Department of Electrical Engineering, Tsinghua University, Beijing.
Bai
J
J
Zhang
L
L
D000054:Acceleration; D000337:Aerospace Medicine; D001415:Back; D002498:Centrifugation; D003198:Computer Simulation; D006112:Gravitation; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D011187:Posture; D011312:Pressure; D011652:Pulmonary Circulation