In an ejection event, the catapulting of the aircrew seat induces a large acceleration pulse to the seat pan. The seat cushion placed between the seat pan and the aircrew can reduce or amplify the acceleration transmitted from the seat pan to the occupant's spine, thereby decreasing or increasing the risk of spinal injury. Therefore, the spinal injury prevention and reduction performance is an important safety issue of ejection seat cushions. The safety performance of a seat cushion depends on its mechanical properties under impact (impact properties). A quasi-linear, visco-elastic model is used to characterize the impact properties of ejection seat cushions. Static elastic response is obtained from quasi-static tests of cushions and is used to determine the instantaneous elastic response based on the relationship between them. The reduced relaxation function is determined from loading tests using numerical inverse convolution. Wavelets are introduced for the non-parametric expression of the reduced relaxation function to improve the accuracy of estimation, and wavelet decomposition is used to eliminate inertial effect and measurement noises.
Characterization of ejection seat cushions by a quasi-linear, visco-elastic model
Kennzeichnung von Schleudersitzkissen durch ein quasi-lineares viskoelastisches Modell
2003
2 Seiten, 4 Bilder, 4 Quellen
Aufsatz (Konferenz)
Datenträger
Englisch
Injury potential of ejection seat cushions.
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