Abstract:
A method and apparatus for side impacting testing of motor vehicles at a sub-system level. By advancing a side impact barrier into the vehicle shell mounted on the fixture at a predetermined speed, full-scale crashworthiness for side impact collisions can be predicted, thereby significantly reducing development cost and time. The fixture includes a base for supporting the vehicle shell, a side portion for reinforcing a lateral side of the vehicle shell and protecting against deformation and a roll-over prevention structure. The fixture additionally includes a plurality of casters attached to the base.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention generally relates to testing of motor vehicles for structural integrity and occupant protection, and more particularly relates a method and apparatus for side impact testing of motor vehicles at a sub-system level. 
     2. Discussion 
     Prior to production, motor vehicles are subjected to full-scale crash testing to ensure structural integrity and occupant protection. Due to the amount of domestic and foreign impact standards and other requirements a manufacturer may self-impose, full-scale testing involves significant monetary and time commitments. Typically, prototype vehicles are specifically developed for testing and are scrapped after a single impact test. It is desirable to limit the use of full-scale testing to verification of vehicle design for crashworthiness to the extent possible. 
     It is known to employ computer modeling to simulate impact testing. Such tools have proven to be extremely valuable in initial design of vehicles and vehicle components. However, due to the dynamic interaction between the numerous components of a vehicle, it is impossible to precisely evaluate the crashworthiness of a vehicle through computer modeling. Therefore, it is desirable to conduct impact testing at a sub-system level in order to more accurately predict the crashworthiness of a vehicle prior to full-scale impact testing. 
     SUMMARY OF THE INVENTION 
     It is a principal object of the present invention to provide a method and apparatus for impact testing a vehicle shell to predict vehicle crashworthiness at a sub-system level. 
     It is another object of the present invention to provide a method and apparatus for significantly reducing development time and cost necessary to satisfy full-scale impact test requirements. 
     In one form, the present invention provides a fixture for impact testing a vehicle shell to predict vehicle crashworthiness at a sub-system level. The fixture includes a base having an upper surface for securing the vehicle shell thereto. The fixture further includes a side support structure interconnected to the base. The side support structure is operative to reduce deformation to a first lateral side of the vehicle shell when a second lateral side of the vehicle shell is subjected to impact. Additionally, the fixture includes a plurality of casters attached to the base. 
     In another form, the present invention provides a method of impact testing a vehicle shell to predict vehicle crashworthiness in a side impact at a subsystem level. The method includes the general steps of: (1) providing a fixture; (2) mounting the vehicle shell to the fixture; (3) impacting the vehicle shell with a barrier at a predetermined speed; and (4) analyzing the vehicle shell to predict vehicle crashworthiness. 
    
    
     Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from a reading of the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an environmental view illustrating a fixture constructed in accordance with the teachings of the present invention shown operatively associated with a vehicle shell and an impact sled. 
     FIG. 2 is an enlarged perspective view of the fixture of the present invention. 
     FIG. 3 is a flow diagram illustrating the general steps of the preferred method of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference generally to the drawings, a fixture for impact testing a vehicle shell to predict vehicle crashworthiness at a sub-system level is generally identified in the drawings with reference numeral  10 . The fixture  10  is shown in FIG. 1 operatively arranged with a vehicle shell  12  and a mobile unit or impact sled  14 . 
     Among the various tests which are generally conducted on most motor vehicles is a side impact test in which a side impact barrier representative of a vehicle is driven into a full-scale vehicle at a pre-determined speed. The energy from the impact is primarily absorbed by one lateral side of the vehicle. Side impact testing is conducted to assess vehicle crashworthiness (e.g. intrusion within the passenger compartment). It is this particular test for which the fixture  10  of the present invention is specifically designed. However, the teachings of the present invention are applicable to other types of crashworthiness testing. 
     With continued reference to FIGS. 1-2, the fixture  10  of the preferred embodiment of the present invention will now be further discussed. The fixture  10  is shown to include a base including a pair of spaced apart beams or rails  14  and  16 . The spaced apart beams  14  and  16  are preferably parallel to one another and each include flat upper surfaces  17  for supporting the vehicle shell  12 . 
     The fixture  10  further includes an intermediate portion  18  interconnecting the first and second rails  14  and  16 . In the embodiment illustrated, the intermediate portion  18  includes a pair of vertically spaced apart rails  20  and  22  which cooperate to support an adjacent lateral side of the vehicle shell  12  and thereby minimize deformation during side impact testing. The first and second rails  20  and  22  of the intermediate portion  18  are interconnected by a pair of rail segments  24  and  26  welded or otherwise fastened to opposite ends of the rails  20  and  22 . The rail segments  24  and  26  are in turn welded or otherwise suitably attached to a first end  28  of each of the horizontal rails  14  and  16 . For structural integrity, a diagonal brace  30  is disposed between each of the horizontal rails  14  and  16  and a corresponding one of the rail segments  24  and  26 . 
     The fixture  10  is further shown to preferably include a roll-over prevention structure  32  interconnected to the base and upwardly extending. The roll-over prevention structure  32  is operative to prevent the vehicle shell  12  from rolling over when subject to impact. In the embodiment illustrated, the roll-over prevention structure  32  includes a substantially horizontal member  34  adapted to be disposed immediately above roof  36  of the vehicle  12 . The roll-over prevention structure  32  further includes a substantially vertical member  38  interbetween the base and the substantially horizontal member  34 . As shown, the vertical member  38  is welded or otherwise suitably attached to the vertically spaced apart rails  20  and  22  of the intermediate portion  18 . 
     In the preferred embodiment, the elements of the fixture  10  are constructed from steel. However, alternate material of sufficient strength may be employed. 
     The fixture  10  of the present invention is further shown to include a plurality of castors  40 . As shown, the fixture  10  preferably includes four (4) castors. The castors  40  are of conventional construction and permit vertical adjustment of the fixture  10  in a known manner. As a result, the height of the vehicle shell  12  can be adjusted to accommodate specific testing requirements. Additionally, the castors  40  facilitate movement of the fixture  10  before and after impact testing. 
     In use, the vehicle shell  12  is impacted with a device such as a side impact barrier  42  carried by a cart or impact sled  44 . The impact sled  44  is illustrated to include a plurality of wheels  46 . The size and weight of the impact sled  44  are chosen for the specific crashworthiness testing involved. More specifically, the weight and height of the impact sled  44 , among other factors, are chosen such that impact testing of the vehicle shell  12  is representative of full scale impact testing. Any desired form of device desired may be used to perform the impact. 
     With continued reference to FIGS. 1-2 and additional reference to FIG. 3, the preferred method of the present invention will be described. The first general step  100  of the method of the present involves mounting the vehicle shell  12  to the fixture  10 . The vehicle shell  12  is supported on the upper surfaces  17  of the horizontal rails  14  and  16  of the base. Preferably, the vehicle shell  12  is welded or otherwise suitably fastened to the rails  14  and  16 . Similarly, the horizontal member  34  is welded or otherwise suitably attached to the roof  36  of the vehicle shell  12 . 
     The second general step of the method of the present invention  110  involves supporting a first lateral side of the vehicle shell  12  with the fixture  10 . As noted above, support is provided by the vertically spaced apart rails  20  and  22  of the intermediate portion  18 . 
     The next general step  120  of the method of the present invention involves stabilizing the vehicle shell  12  with the fixture  10  to prevent roll-over. The roll-over prevention structure  32  of the fixture  10  extends adjacent the first lateral side of the vehicle end adjacent the roof  36 . 
     The next general step  130  of the present invention involves impacting a second lateral side of the vehicle shell  12  with the side impact barrier  42  at a predetermined speed. In one application, the vehicle shell  12  is impacted with the side impact barrier  42  at a speed of approximately 14 miles per hour. However, it will be appreciated by those skilled in the art that the speed of impact may be varied as desired. The impact sled  44  is advanced into the vehicle shell  12  in a conventional manner to contact the vehicle shell  12  at a predetermined height. 
     The final general step  140  of the present invention involves analyzing the vehicle  12  shell to predict vehicle crashworthiness. The occupant compartment intrusion and other factors calculated during the impact testing of the vehicle shell  12  are indicative of full scale impact testing. Upon analyzing the test results, subsequent design iterations of the components of the vehicle shell  12  may be made to improve crashworthiness of the vehicle shell  12  (e.g. to reduce intrusion into the passenger compartment). 
     While the above description constitutes the preferred embodiment of the invention, it will be appreciated that the invention is susceptible to modification, variation, and change without departing from the proper scope or fair meaning of the accompanying claims.