A Four-Degree-of-Freedom Lumped Parameter Model of the Seated Human Body

摘要

A four-degree-of-freedom lumped parameter model is tentatively proposed to study the problem of the vertical accelerations of the seated human body such as may be imposed by aircraft ejection systems. The coefficients defining the mass distribution and the spring and damping rates of the connecting links are obtained from experimental data. The way in which these coefficients are derived is described in the report. Development of the model is preceded by a study of the driving point impedance of generalized multi-degree of freedom systems. This study was carried out to determine how much reliance should be placed on experimental impedance measurements in the construction of the model. It is concluded that a reasonable representation of the dynamics of a seated human subject can be obtained by the four-degree-of-freedom lumped parameter model, but that there exists a surprisingly small amount of usable data, indicating that a sophisticated experimental program should be initiated to examine in detail particular aspects of body dynamics. (Author)