MGA Continues to Lead Vehicle Rollover Protection Development
Rollover accidents cause a disproportionate number of injuries and deaths across the country. For this reason, as well as to be considered federally compliant for ejection mitigation, a builder must include rollover testing in vehicle development. The federal government has a requirement for ejection mitigation, which means a vehicle must have systems in place to reduce the likelihood of occupants leaving the vehicle through the side windows. Rollover testing and vehicle responses can be equally vexing for manufacturers. Rollover incident catalysts range from sliding, road departure, foreign objects, and countless others. Vehicle dynamics will depend on many variables like weight, height, suspension, speed, etc.
MGA has been performing full vehicle rollover testing for over 15 years. There are static, dynamic, and driving test procedures in place to recreate nearly any rollover scenario encountered in the vehicle developmental process. Besides the test modes themselves, the data captured during this event is fully customizable. Sensors can be placed anywhere in or on the vehicle itself, as well as the ability to monitor the vehicles’ own sensor system. Crash dummy dynamics are captured by high speed cameras located inside and outside the vehicle. These cameras monitor the entire event, and can be placed nearly anywhere to capture the desired point of interest. The following highlights the test methods most requested by vehicle manufacturers, but does not fully encompass everything MGA has to offer. Developmental standards and methodologies are constantly changing and upgrading, and we strive to work with our customers to achieve these goals.
Ramp testing consists of propelling half of a vehicle over an adjustable ramp. When the passenger-side of the vehicle launches, the vehicle will roll along its center axis. The driver-side would rotate “down.” By adjusting the height of the ramp and speed of the vehicle, varying roll rates (degrees per second) and roll angles can be achieved.
A soil or curb test is performed by placing a vehicle on a cart. This cart is propelled down the track until it impacts heavy industrial shocks to finely control its deceleration. The cart can also be decelerated by a series of pneumatic brakes. Each method has varied deceleration rates and adjustability to meet the desired test result of the manufacturer. Upon impact with the shocks, the vehicle will continue to move forward, per Newton’s first law. For a soil test, the vehicle will enter a large sand box. The friction of the sand will slow the vehicle, and roll it over. For a curb test, the vehicle is held by steel plates. This allows the opposite side of the vehicle to rotate.
Ditch testing recreates a common rollover situation along a road. A steep embankment easily trips cars into a roll situation. MGA’s ditch wall uses hydraulic rams to adjust the wall angle from 35°-55°. The angle the car approaches the ditch wall is adjustable from 5°-20°.
For the Russian market, a new regulation is in the works to require an emergency call to authorities in the event of a rollover (Europe has variations of this regulation as well). These tests are referred to GLONASS rollover, which is Russia’s own GPS. There is a static test where a vehicle is strapped to a rotisserie, and is rotated in multiple directions and speeds. The dynamic test is an aggressive variation of a ramp test.
The FMVSS 208 Dolly Rollover / SAE J2114 Roll is a destructive test that requires the vehicle to rest upon a cart that is set to 23°. The cart impacts shocks at 30mph and quickly decelerates, which causes the vehicle to continue forward and roll.
Immunity testing refers to a group of driving events that recreate real world scenarios. Tests such as J-hook or quick lane changes will induce roll characteristics into the vehicle. Immunity testing can be considered as “due-care” testing. This is done so that “normal” driving maneuvers and conditions will not trigger a rollover response from the vehicle. This is to protect the occupants from unnecessary airbag deployment.
Robotic Steer-Induced Rollover is the newest technology within MGA’s arsenal of rollover capabilities. A steering robot capable of driving the car (steering wheel, gas, and brake pedals) along a pre-determined path allows for dynamic rollover testing. The robot will maneuver the vehicle into a sand trap, which will roll the vehicle like the controlled soil test that takes place inside. Using the robot allows for the most realistic dummy and vehicle interaction during a dynamic situation.
Rollover testing plays an important role in vehicle development, given that rollover incidents account for a disproportionate number of fatalities and injuries. For over 15 years, MGA has been conducting comprehensive vehicle rollover testing, capable of replicating nearly any rollover scenario that may arise during the developmental process. Whether for the purposes of airbag algorithm refinement or occupant studies, MGA is committed to partnering with customers to help them achieve their desired objectives.