A Study of the Dynamic Model Technique in the Analysis of Human Tolerance to Acceleration
Abstract
This report is concerned with the study of human tolerance to abrupt accelerations where the duration times are less than one tenth of a second. A dynamic model analogous to the human body, consisting of a spring-mass system, is used in the analysis. When an acceleration is applied to the base of the spring, the response of the system is similar to the dynamic response of the human body under the influence of the same acceleration. If the input acceleration-time history is assumed to have a simple form, such as that represented by a step, rectangular or ramp function, the solution of the motion of the model in terms of the spring deflection and mass acceleration is relatively simple. The basic mathematics involved in obtaining this dynamic response is developed in the Appendices for a variety of simple input forms. The tolerance criterion adopted consists of setting a limit on the mass acceleration attained by the mass, so that the peak mass acceleration achieved under given input conditions is an important parameter. A linear, undamped, single degree of freedom system is used as the basic model, but the influence of dumping and non-linearity of the spring on tolerance limits is also considered. The output of the model, in terms of the mass acceleration, depends on the input duration and damping but can be as much as twice the value of the input acceleration. In the impact region, velocity change is an important criterion.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1965
- Accession Number
- ADA433611