Crash impact attenuator systems and methods

Abstract

A crash attenuator system for deployment in front of a fixed structure includes a rail extending along a length of the crash attenuator system and a plurality of diaphragms initially disposed in spaced relation along the length of the rail. Each of the plurality of diaphragms moves along the rail, so that when a front end of the crash attenuator system receives an impact force from a vehicle, a first one of the diaphragms moves rearwardly along the rail and impacts a second one of the diaphragms so that both the first and second diaphragms move further rearwardly along the rail, this process continuing with additional ones of the diaphragms until the impact forces have been fully attenuated. A tearing member on the crash attenuator system engages material forming a tearable member of the crash attenuator system, the tearing member tearing material forming the tearable member to increase attenuation of the impact force.

1 . A crash attenuator system for deployment in front of a fixed structure, the system comprising:
 a rail extending along a length of the crash attenuator system;   a plurality of diaphragms initially disposed in spaced relation along the length of the rail, each of the plurality of diaphragms having a base end adapted to be movably engaged with the rail, so that when a front end of the crash attenuator system receives an impact force from an errant vehicle, a first one of the plurality of diaphragms moves rearwardly along the rail and impacts a second one of the plurality of diaphragms so that both the first and second ones of the plurality of diaphragms move further rearwardly along the rail, this process continuing with additional ones of the plurality of diaphragms until the impact forces have been fully attenuated; and   a tearing member on the crash attenuator system which is adapted to engage material forming a tearable member of the crash attenuator system, relative motion occurring between the tearing member and the tearable member when an impact force strikes the crash attenuator system so that the tearing member tears the tearable member, thereby increasing attenuation of the impact force, the tearable member being tuned to optimize the tearing of the tearable member, the tearable member being tuned so that portions of the tearable member toward the front end of the crash attenuator system are softer, and thus capable of less force attenuation, than portions of the tearable member toward a back end of the crash attenuator system;   wherein the tearable member extends along at least a portion of the length of the crash attenuator and includes a plurality of holes disposed therein, the plurality of holes extending along a length of the tearable member and spaced lengthwise from one another, the tearing member being engaged with one of the plurality of holes so that when an impact force is applied to the crash attenuator, relative motion occurs between the tearable member and the tearing member and causes the tearing member to tear the material between adjacent ones of the plurality of holes, thereby creating a continuous slot, the tearing of the material functioning to attenuate the impact force.   
     
     
         2 . (canceled) 
     
     
         3 . The crash attenuator system as recited in  claim 1 , wherein the tearing member is disposed on one of the plurality of diaphragms and comprises a bolt. 
     
     
         4 . The crash attenuator system as recited in  claim 3 , wherein the tearing member is disposed on a base end of the first one of the plurality of diaphragms. 
     
     
         5 . The crash attenuator as recited in  claim 1 , wherein the tearing member comprises a plurality of tearing members. 
     
     
         6 . (canceled) 
     
     
         7 . The crash attenuator as recited in  claim 1 , wherein the tearable member is tuned by arranging the plurality of holes so that the plurality of holes are not evenly spaced along the length of the tearable member. 
     
     
         8 . The crash attenuator as recited in  claim 7 , wherein adjacent ones of the plurality of holes nearer to the front end of the crash attenuator are more closely spaced than adjacent ones of the plurality of holes closer to the back end of the crash attenuator. 
     
     
         9 . The crash attenuator as recited in  claim 1 , wherein the tearable member is tuned by arranging the holes so that the plurality of holes are not uniform in size, respective to one another. 
     
     
         10 . The crash attenuator as recited in  claim 8 , wherein ones of the plurality of holes nearer to the front end of the crash attenuator are larger and more elongated than those of the plurality of holes which are located closer to the back end of the crash attenuator. 
     
     
         11 . The crash attenuator as recited in  claim 1 , wherein the tearable member is tuned so that the material forming the tearable member is thinner toward the front end of the crash attenuator, and thicker toward the back end of the crash attenuator. 
     
     
         12 . The crash attenuator as recited in  claim 1 , wherein the tearable member is tuned by comprising the tearable member of a plurality of stages as it extends from of the front end of the crash attenuator toward the back end of the crash attenuator, wherein a first stage toward the front end of the crash attenuator is softer than a second stage toward the back end of the crash attenuator. 
     
     
         13 . (canceled) 
     
     
         14 . The crash attenuator as recited in  claim 12 , wherein the first stage is softer because the material forming the first stage is thinner than the material forming the second stage. 
     
     
         15 . The crash attenuator as recited in  claim 12 , wherein the first stage is softer because the holes of the plurality of holes which are disposed in the first stage are closer together than the holes of the plurality of holes which are disposed in the second stage. 
     
     
         16 . The crash attenuator as recited in  claim 12 , wherein the first stage is softer because the holes of the plurality of holes which are disposed in the first stage are larger in size than the holes of the plurality of holes which are disposed in the second stage. 
     
     
         17 . The crash attenuator as recited in  claim 1 , wherein the rail comprises first and second outer rails spaced apart in a widthwise direction, and the tearable member comprises a center rail. 
     
     
         18 . The crash attenuator as recited in  claim 1 , and further comprising a plurality of fender panels disposed along each side of the crash attenuator along its length, wherein frontmost ones of the plurality of fender panels are adapted to slide alongside of rearmost ones of the plurality of fender panels when the crash attenuator is impacted by a vehicle. 
     
     
         19 . The crash attenuator as recited in  claim 1 , and further comprising a nose box disposed at the frontmost end of the crash attenuator. 
     
     
         20 . The crash attenuator as recited in  claim 1 , wherein the tearable member is stationary and the tearing member moves responsive to the impact force. 
     
     
         21 . (canceled) 
     
     
         22 . A method of attenuating a crash impact force imposed by an errant vehicle which would otherwise strike an immovable object, the method comprising:
 receiving an impact force at a front end of a crash impact attenuator having a base portion and an upper attenuator portion;   causing one or more members of the upper attenuator portion to move rearwardly along the base portion responsive to the impact force; and   causing a tearing member disposed on the crash impact attenuator to tear tearable material disposed on the crash impact attenuator as the one or more members of the upper attenuator portion move rearwardly, wherein tearing of the material acts to attenuate the impact force, the tearable material being tuned to optimize the tearing of the tearable member so that portions of the tearable material toward the front end of the crash impact attenuator are softer, and thus capable of less force attenuation, than portions of the tearable member toward a back end of the crash attenuator system.   
     
     
         23 . The method as recited in  claim 22 , wherein the tearing member is a projection disposed on one of the one or more members of the upper attenuator portion which is initially engaged with a hole formed in the tearable material. 
     
     
         24 . The method as recited in  claim 23 , wherein there are a plurality of holes in the tearable material, arranged longitudinally in spaced relation, and the tearing step comprises tearing the tearable material between the initially engaged hole and an adjacent one of the plurality of holes, to form a slot. 
     
     
         25 . The method as recited in  claim 24 , wherein the one or more members of the upper attenuator portion comprise one or more diaphragms, and the tearable material comprises a rail forming a part of the base portion. 
     
     
         26 . The method as recited in  claim 24 , wherein ones of the plurality of holes nearer to the front end of the crash attenuator are larger and more elongated than those of the plurality of holes which are located closer to the back end of the crash attenuator. 
     
     
         27 . The method as recited in  claim 22 , wherein the tearable member is tuned so that the material forming the tearable member is thinner toward the front end of the crash attenuator and thicker toward the back end of the crash attenuator. 
     
     
         28 . A crash attenuator system for deployment in front of a fixed structure, the system comprising:
 a rail extending along a length of the crash attenuator system;   a plurality of diaphragms initially disposed in spaced relation along the length of the rail, each of the plurality of diaphragms having a base end adapted to be movably engaged with the rail, so that when a front end of the crash attenuator system receives an impact force from an errant vehicle, a first one of the plurality of diaphragms moves rearwardly along the rail and impacts a second one of the plurality of diaphragms so that both the first and second ones of the plurality of diaphragms move further rearwardly along the rail, this process continuing with additional ones of the plurality of diaphragms until the impact forces have been fully attenuated; and   a tearing member on the crash attenuator system which is adapted to engage material forming a tearable member of the crash attenuator system, the tearing member and the tearable member being relatively movable when an impact force strikes the crash attenuator system so that the tearing member tears the tearable member, thereby increasing attenuation of the impact force;   the tearable member comprising the rail.