Abstract:

To shorten the time of ejection seat through the canopy, and to ensure pilot to safely escape and survive , the application of cutting technique with miniature detonating cord (MDC) in aviation ejection escape system is proposed. Firstly, experimental study on the cutting aeronautical polymethyl methacrylate (PMMA) plate with a serial of semicircle MDC, which are made of royal demolition explosive (RDX), high melting explosive (HMX), Hexanitrostilbene II (HNSII) and two different metal materials (Pb and Al), is performed. Spalling phenomenon in the PMMA due to MDC cutting is observed. The best explosive type, covered material and charge quantity suitable for MDC are determined. Subsequently, According to experimental result from PMMA component test, the process of cutting the real fullsize warcraft canopy is simulated using threedimension dynamic nonlinear explicit code LSDYNA3D，herein MDC is installed along the center of canopy. In FEA, ALE algorithm is used to model the flow properties of explosive after detonation. Automatic surface to surface contact type is selected to implement fluid structure interaction between explosive and PMMA. Damage behaviors of PMMA subjected to detonation shock are represented by using continuum damage dynamic constitutive model accompanying with the spalling property. Lastly, cutting depths corresponding to given charge quantities are obtained by numerical simulation, which well agree with the experimental results. As a consequence, experiment on the PMMA plate is able to guide canopy test.

Key words: miniature , detonating , cord,  , cutting,  , PMMA,  , ejection , escape , system,  , spalling,  , computer , simulation