Nonlinear Decelerator for Payloads in Aerial Delivery Systems. I: Design   and Testing
  We study the dynamics and the optimization of the shock deceleration supported by a payload when its airborne carrier impacts the ground. We build a nonlinear elastic model for a container prototype and an elastic suspension system for the payload. We model the dynamics of this system and extract information on maximum deceleration, energy transfer between the container and payload, and energy resonant damping. We designed the system and perform lab experiments for various terminal velocities and types of grounds (cement, grass, sand water, etc.). The results are compared with the theoretical model and results are commented, including predictions for deceleration at different types of ground impact. The results can be used for aerial delivery systems, splash-down of capsules, recoveries, weather balloons, coastal surveying systems, or the new introduced goal-line technology in sport competitions. 
T. Lyons, M. Ginther, P. Mascarenas, E. Rickard, J. Robinson, J.   Braeger, H. Liu and A. Ludu
cond-mat.soft