Performance of an elastic polymer foam cushion in attenuating responses of shipboard standing-men to ship vertical shock

How to protect shipboard personnel from the shock events induced by underwater explosion is a very interesting subject for ship designers. In this study, the potential attenuation performance of an elastic polymer foam cushion inserted between standing-man and ship deck is investigated theoretically. An 8-degree-of-freedom nonlinear lumped-parameter model is applied to predict the standing-man’s biodynamic responses and injury potential. The cushion is modeled by a chain of masses separated by nonlinear springs and dampers in parallel to simulate the micro inertia, stiffness and rate-dependent effects exhibited by common polymer cellular materials. Two variables, kickoff speed ratio and deck reaction force ratio corresponding to two types of typical injury potential of standing-men, are defined as evaluation parameters. The influence of critical buckling force level, material rate dependent effect as well as some other design factors on the attenuation performance of the foam cushion is discussed in detail. Some general design rules are also presented.