Semi-Tractor Trailer Crash Test
Pre-Test Verification of the Impact Alignment
Bullet Vehicle, Post Test
This test involved impacting a variety of compact sedans with a semi-tractor trailer weighing 65,000 lbs (29,550 kg) GVW at an impact speed of 65 mph (106 km/h). After being rejected by other testing agencies, the client approached GMH Engineering because of our reputation for finding innovative and cost effective solutions to meet difficult testing requirements.
Due to the specified impact speed, and the possible post-impact vehicle dynamics, driving the semi-tractor trailer (bullet vehicle) into the impact vehicle was deemed to be an unacceptable risk. A methodology was proposed to tow the bullet vehicle into the impact using a second semi-tractor as a tow vehicle. GMH Engineering designed and fabricated a two part offset towing rig that allowed the tow vehicle to be positioned to the front left of the bullet vehicle during the tow-in and then separate from the bullet vehicle just prior to impact. One part of the tow rig was attached to the tow vehicle and the second part to the bullet vehicle. An explosive bolt joined the two parts of the tow rig during the tow-in phase of the test. Just prior to impact, the explosive bolt was fired allowing the tow vehicle to proceed unhindered as the bullet vehicle made contact with the stationary sedan (target vehicle). The bullet vehicle's air brake system was also modified. An electrical control system was fabricated to allow the tractor and trailer brakes to be activated at impact to bring the bullet vehicle to a stop.
The target vehicle was instrumented for both vehicle and driver dynamics using an on-board DataBRICK data acquisition system. An Anthropomorphic Test Dummy (ATD) was used as a driver surrogate in the target vehicle. High speed cameras were mounted on board the target vehicle and were also mounted off board. Three impact tests were successfully accomplished using the same bullet vehicle and three different target vehicles. The bullet vehicle was rebuilt in the field after the first and second test due to the significant damage the impacts caused to the semi-tractor's steering, suspension and undercarriage.
Accomplishing this project under budget, and in a timely manner, required innovation, hard work and a skilled group of experienced, hands-on engineers and technicians. GMH Engineering strives to bring this level of service to all of our customer's projects.
Post-Test Vehicle Positions
Test Site, Vehicle Preparation Area