Method and apparatus for shock wave mitigation

Abstract

A method and apparatus for mitigating blast compression waves is disclosed. The apparatus has a housing having an open end, and a piston slidably received in the open end of the housing in a substantially airtight engagement therewith. The piston and the housing define an interior wherein a compressible substance is confined. When a blast wave impacts the impact face of the piston and drives the piston toward the base of the housing, a shock wave is induced in the compressible substance. The shock wave is reflected by the base of the enclosure and the interior surface of the piston to mitigate the impact of the blast wave.

1 . An assembly for mitigating a blast compression wave, the assembly comprising: 
 a housing having a base wall, an outwardly extending wall, and an open end;    a piston comprising an impact face and an interior face, the piston being slidably received in the housing in a substantially airtight engagement therewith, the piston, the base wall and the outwardly extending wall defining an interior; and    a compressible substance confined within the interior, whereby the blast wave impacts the impact face of the piston and drives the piston toward the base of the housing thereby inducing a shock wave in the compressible substance within the interior, the shock wave being reflected by the base of the enclosure and the interior surface of the piston to mitigate the impact of the blast wave.    
   
   
       2 . The apparatus of  claim 1  wherein the piston is formed of steel.  
   
   
       3 . The apparatus of  claim 1  wherein the piston has a thickness from the blast-impact face to the interior face of between approximately 1 centimeters to approximately 10 centimeters.  
   
   
       4 . The apparatus of  claim 1  wherein the area of the blast impact face of the piston is between approximately 0.1 meters and 0.15 meters.  
   
   
       5 . The apparatus of  claim 1  wherein the mass of the piston is between approximately 40 kilograms and approximately 60 kilograms.  
   
   
       6 . The apparatus of  claim 1  wherein outwardly extending wall is cylindrical and extends outwardly from the base wall between approximately 0.05 meters and 0.2 meters.  
   
   
       7 . The apparatus of  claim 1  wherein outwardly extending wall comprises opposing side walls and opposing upper and lower walls.  
   
   
       8 . The apparatus of  claim 1  wherein the impact face of the piston is substantially planar.  
   
   
       9 . The apparatus of  claim 1  wherein the base wall is substantially planar.  
   
   
       10 . A method for mitigating blast compression waves, the method comprising the steps of: 
 providing a housing having a base wall and an outwardly extending wall, and a piston slidably received in the housing and in substantially sealing engagement therewith, the housing and piston defining an interior;    inducing a shock wave in the interior of the housing through the piston receding into the interior upon the impact of the blast wave; and    reflecting the shock wave within the interior of the housing.    
   
   
       11 . The method of  claim 10  further comprising the step of increasing the duration of the force upon the base wall of the housing as compared to the duration of the force from the blast wave.  
   
   
       12 . The method of  claim 10  wherein the step of reflecting the shock wave within the interior of the housing comprises the step of repeatedly reflecting the shock wave between the base wall and an interior face of the piston until the piston is stopped and the shock wave attenuated.  
   
   
       13 . The method of  claim 10  wherein the step of providing a housing and a piston slidably received in the housing and in substantially sealing engagement therewith, the housing and piston defining an interior further comprises the step of providing a compressible gas within the interior.  
   
   
       14 . A method for mitigating blast compression waves, the method comprising the steps of: 
 providing a housing having a base wall and an outwardly extending wall, and a piston slidably received in the housing and in substantially sealing engagement therewith, the housing and piston defining an interior;    conserving substantially the impulse of the blast wave within the interior of the housing and piston; and    increasing the duration of the force upon a base wall of the housing.