AIRCRAFT PASSENGER-SEAT-SYSTEM RESPONSE TO IMPULSIVE LOADS.

摘要

The report is divided into four chapters. Chapter 1describes the mathematical model consisting of a visco-elastic occupant (control of joint stiffness through muscle tension) and an elastic-plastic seat structure. A comparison is made of the computer output and a full-scale dynamic test of a modern transport seat using instrumented dummies. Chapter 2presents a spectrum of design data based on results obtained from the computer program. Chapter 3presents a discussion of load limiting and other structural and detail design concepts appropriate to maintaining good restraint of the occupant. Stress concentrations under dynamic load are explored,and the results of experimental tests are presented to show that components which have stress raisers may absorb only very small amounts of energy prior to failure. Chapter 4discusses the problem of head impact for the jackknifing passenger when restrained by seat blet alone. A computer study has been made which allows a correlation of head impact velocity and 'cushioning material'thickness with the presently known human tolerance limits to deceleration. It is shown that the permissible head impact velocities will probably be in the order of one-third to one-half those which result in 64-foot-per-second impacts. (Author)