Frontal Impact Sled Testing Two (2) frontal impact accelerator sleds are available through the MGA ¨C Michigan Test Laboratories. This sled is used for component and developmental testing for the automotive industry. This sled is very versatile in that many issues can be addressed including the development of airbags (FMVSS 208), luggage retention characteristics, the integrity of seats, child seats, seatbelts, and interior components, as well as the overall simulation of crash kinematics. The sled consists of a thrust column, driven by high-pressure air, attached to a carriage. The main system can reach a maximum speed of 50 MPH and can accelerate the carriage up to 63 G¡¯s with a 2200 lb payload or 39 G¡¯s with a 4400 lb payload. The sled has a high weight capacity with the ability to propel whole vehicles. MGA also has a lighter weight sled capable of reaching a maximum speed of 90 mph and 100 g's with a 500 lb payload. MGA¡¯s docking system allows for a quick change of carriages from one setup to another. The system involves the use of air bearings, allowing sections of track to float from one location to another. A carriage is changed by sliding it onto a transfer track and replacing it with a track holding the new carriage. The docking system allows carriages to be swapped in less than 15 minutes. MGA¡¯s sled design permits the carriage to be easily offset up to 30 degrees in 2.5 degree increments. This feature allows angled impacts to be simulated easily without modifications to the sled buck. Complementing the sled testing is a complete range of fabrication services in which vehicle bucks can be built or modified. The combination of the rotating carriage and fabrication capabilities results in an ideal test center for defense litigation forensic testing. A metering pin and orifice control the flow of air against the piston and thereby the acceleration profile. The most important part of the simulation is the shape of the metering pin. MGA has developed the AutoPin? program that allows virtually any desired sled pulse to be matched. The program inputs a target pulse and designs a pin that will closely match the desired acceleration. This design is sent to the MGA Fabrication and Design Center and the pin is usually available within two to three days. A computerized data acquisition system allows up to 80 channels to be recorded. Signal conditioning is available for strain gage accelerometers and load cells, piezoelectric transducers, contact sensors, and linear displacement potentiometers. Raw data plots and preliminary injury criteria values are available rapidly after testing and results can be evaluated using data overplotting and occupant injury value comparisons. Digital high-speed color videos are used to photographically record the event. Up to five high-speed video cameras can be attached to the carriage, and, using adjustable camera booms, various photographic views can be achieved.
MGA has a wide range of dummies available for sled testing. These include the following:
-Hybrid III 5 %
-Hybrid III 3-year-old
-Hybrid II 6-year-old
-Hybrid III 50%
-Hybrid III 6-year-old
-12-month-old CRABI
-Hybrid III 95%
-Hybrid II 50%
-3-year-old Airbag Dummy
All MGA facilities are A2LA-accredited, and a professional, courteous, and experienced staff is available to assist the automotive industry in regard to safety issues. Side Impact Sled Testing MGA¡¯s side impact accelerator sled was developed to realistically simulate the kinematics of a full-scale side impact crash test. Our approach uses a ¡°two carriage¡± system driven by a high-pressure air piston. The upper carriage simulates the door response, while the lower carriage mimics the unstruck side of the vehicle. The response between the upper and lower carriages is controlled via an onboard pneumatic cylinder. With this approach, both the intruding door and floor pan acceleration evident in an actual crash test can be simulated. The accelerator sled is operated by forcing high-pressure air (up to 3000 psi) against a piston attached to a thrust column. When the system is fired, the thrust column piston accelerates the upper carriage, which builds up pressure in the on-board carriage pneumatic cylinder. When the forces generated in the pneumatic cylinder overcome the lower carriage braking forces, the lower carriage begins to move. Presented in the figure below is a typical side impact sled test setup. As shown here, the door trim and other components are mounted to a flat plate attached to an A-frame that is fixed to the upper carriage. The seat and dummy are positioned on the lower carriage. Since the responses of the upper and lower carriage can be tuned to match the struck door and un-struck side responses from a crash test, the spacing of the interior components, seat, and dummy can be identical to the vehicle. This provides an ideal tool for evaluating not only the overall effectiveness of side impact airbags, but also other variables such as deployment rates, occupant inner panel closing speeds, and energy absorbing materials. MGA has also developed a test that simulates the 18 MPH pole impact per FMVSS 201U requirements. The approach utilizes the dual carriage method with the pole intruding into a collapsing side structure. The vehicle structure is hinged at each end and mimics the movement of the pillars and side rails in a pole impact crash test. This system is ideal for the development of curtain airbags in that the only components needed for each test are the interior trim components and air bag assembly. The hinged vehicle structure is designed so that multiple tests can be conducted with repeatable and comparable results.
A metering pin and orifice control the flow of air against the piston and thereby the acceleration profile. The most important part of the simulation is the shape of the metering pin. MGA has developed the AutoPin? program that allows virtually any desired sled pulse to be matched. The program inputs a target pulse and designs a pin that will closely match the desired acceleration. The program is specifically set up to simulate upper and lower carriage velocities and accelerations. Typically, metering pins are available within two to three days. A computerized off-board data acquisition system stores digital data recorded during a test. Signal conditioning is available for strain gage accelerometers and load cells, piezoelectric transducers, contact sensors, and linear displacement potentiometers. Raw data plots and preliminary injury criteria values are available rapidly after testing and results can be evaluated using data overplotting and occupant injury value comparisons. Digital high-speed color videos are used to photographically record the event.
All MGA facilities are A2LA-accredited, and a professional, courteous, and experienced staff is available to assist the automotive industry in regard to safety issues.
The sled consists of a thrust column, driven by high-pressure air, attached to a carriage. The main system can reach a maximum speed of 50 MPH and can accelerate the carriage up to 63 G¡¯s with a 2200 lb payload or 39 G¡¯s with a 4400 lb payload. The sled has a high weight capacity with the ability to propel whole vehicles. MGA also has a lighter weight sled capable of reaching a maximum speed of 90 mph and 100 g's with a 500 lb payload. 
