Passive shock mitigation system with sea water metering shock absorber

摘要

Passive apparatus for absorbing the kinetic energy of a collision to protect an underwater structure from damage in a collision which includes a ring suspended by a ring support system so that the ring is positioned between the structure and the expected path of potentially impacting objects. The ring support system includes eight rigid rods which have one end coupled to one of four symmetrically disposed supporting pylons by spherical sleeve bushings and their other end coupled by spherical rod ends to one of four standoff members that are fixed to the top surface of the ring at equal intervals around its circumference. A shock absorber is coupled between each supporting pylon and the ring midway between standoff members by spherical rod ends. The dimensions of the rigid rods and their attachment points to the supporting pylon and the ring are chosen so that the ring may pivot on the rods against the resistance of the shock absorbers in response to an impact, but cannot strike the enclosed object. The preferred embodiment employs a shock absorber in which forces are dissipated when two concentric cylinders are compressively displaced to force sea water from an interior chamber formed by the cylinders. As the cylinders are forced together, the sea water is forced out of the chamber through tapered slots in the outside surface of the inner cylinder. As the cylinders are forced together, the size of the orifices provided by the tapered slots is continuously reduced so that progressively greater force is required to eject the sea water from the chamber.