Apparatus for absorbing mine blast energy

Abstract

The invention reduces the amount of force and acceleration transmitted to the vehicle occupant in a vehicle subject to the shock of a land mine explosion. In the invention, a set of crushable composite tubes are placed between the vehicle floor and the seat of the vehicle. As the floor moves due to the blast loading, the crushable tubes deform, absorbing the energy of the blast and reducing the acceleration transmitted to the seated occupant.

What is claimed is: 
     
       1. An apparatus for reducing force from an exploding mine, transmitted to a seated occupant in a vehicle, the apparatus comprising: a vehicle floor;   a seat attached to the vehicle floor;   armor attached to the seat;   armor attached to the floor;   a seat pedestal for attaching the seat to the vehicle floor;   at least one crush tube for absorbing energy from the exploding mine disposed between the vehicle floor and the seat;   wherein the at least one crush tube is a fiber-reinforced composite structure comprising thin fibers of a strong and stiff material, in a polymer matrix, such fibers aligned along the axial direction of the at least one crush tube;   further comprising a second crush tube which is concentric with the at least one crush tube such that each crush tube carries a portion of the force;   wherein an axial length of the second crush tube is different from an axial length of the at least one crush tube such that one crush tube is loaded before the other.   
     
     
       2. The apparatus of claim 1, wherein the at least one crush tube is disposed vertically between the vehicle floor and the seat. 
     
     
       3. The apparatus of claim 1, wherein the fibers comprise continuous fibers in a polymer matrix. 
     
     
       4. The apparatus of claim 1, wherein the at least one crush tube is made of discontinuous fibers in a polymer matrix. 
     
     
       5. An apparatus for reducing force from an exploding mine or the like, transmitted to a seated occupant in a vehicle, the apparatus comprising: a vehicle floor;   a seat attached to the vehicle floor;   armor attached to the seat;   armor attached to the floor;   a seat pedestal for attaching the seat to the vehicle floor;   at least one crush tube for absorbing energy from the exploding mine disposed between the vehicle floor and the seat;   wherein the at least one crush tube is a fiber-reinforced composite structure comprising thin fibers of a strong and stiff material such as graphite, glass, Aramid, or boron, in a polymer matrix, such fibers aligned along the axial direction of the at least one crush tube;   wherein the at least one crush tube is cone-shaped so that energy absorbed varies with time.