不同抗荷措施与后仰座椅的综合抗荷效果:计算机仿真研究

Combining effects of different anti G techniques and tilt back seat: a computer simulation

目的 利用计算机模型仿真研究多种抗荷措施综合使用的防护效果与其单独使用防护效果间的关系。 方法 利用所建立的适用于仿真 +GZ加速度及先进囊式抗荷系统呼吸 -循环影响及其抗荷效果的多元非线性循环呼吸系统模型 ,对扩大囊覆盖面积抗荷服 (ECGS)、抗荷正压呼吸(PBG)、后仰座椅等抗荷措施单独使用及综合使用时的抗荷效果进行了仿真实验研究。 结果 G耐力的仿真结果与空军航空医学研究所进行人体离心机试验结果及国外部分试验数据基本符合。仿真结果表明 ,通过提高胸内压或增加循环血量的方法来提高 +GZ耐力的抗荷措施如 ECGS、PBG、抗荷动作 (AGSM)等 ,当对下肢施以充分的对抗压时 ,其综合防护效果可看作为各单独防护效果的代数和。后仰座椅由于通过缩短心 -眼垂直距离及降低血液在下身的积聚两种方式提高 +GZ耐力 ,它与其他抗荷措施的综合防护性能高于其单独使用效果之代数和。 结论 各抗荷措施综合抗荷效果并非其各自防护效果的简单相加 ,尤其在使用较大角度后仰座椅时。

Objective The aim of this study is to investigate the relationship between the protective effects of anti G measures used in combination and those used individually. Mehtods Using the multi element, nonlinear mathematical model of human circulatory respiratory system developed for simulating cardiovascular effects of +G Z acceleration and protection afforded by advanced bladder anti G system, computer simulation study was performed to investigate this relationship. Results The simulation results have been shown to compare well with the results of the human centrifuge experiments and some centrifuge data published before. The study demonstrates that when appropriate counter pressure is exerted to lower body, the combined effects of anti G techniques enhancing +G Z tolerance by means of elevating intrathoracic pressure or increasing blood volume, such as ECGS, PBG, and AGSM, may be regarded as a simple algebraic sum of individual effects. Since the tilt back seat enhances +G Z tolerance by means of decreasing the vertical distance between heart and eyes, and decreasing venous pooling in the lower body, the combined effects of tilt back seat and other anti G techniques are higher than the sum of individual effects. Conclusions The relationship between combined and individual effects of the various anti G techniques would not be regarded as simply additive, especially when tilt back seat is used.