Side-impact testing for occupant protection

A new device and test methodology can simulate side-impact crashes accurately using a frontal crash simulator and two hydraulic brake systems.

Because of the increasing losses and casualties due to car accidents, emphasis on the airbag system as an important occupant-restraint system during collision is growing. Interest has been placed especially on side-impact-airbag systems because side-impact crashes result in higher occupant injury values than frontal crashes. Frontal impact involves only deceleration motion during a collision, but side impact involves very complex motions during a very short period, including acceleration and deceleration of the door and B-pillar and dynamic occupant interaction. Accurate simulation of the side-impact crash is important in reducing development time and cost for a side-impact safety system.

In frontal sled tests, the sled pulse is made from the acceleration signal of the B-pillar because it is more stable than other components, as well as for its proximity to occupants. In side-impact sled tests, the signals of the B-pillar and the door area are complex and have a wider variation due to the collision conditions of the moving deformable barrier (MDB) and car. Because side-impact sled tests have used sled signals that could not fully account for the dynamic interaction of the car and the dummy, there have been some differences between sled and MDB test results. Many automotive-safety companies have been working to develop an effective test method to accompany Heidelberg-type side-impact sled tests in which a stationary wall is impacted by a nominal constant-velocity dummy. However, there is still no universally accepted standard component test method. Some test methods that provide relatively accurate results need to undergo a door-assembly change after each test, which adds time and cost to the test. Other test methods do not need a door-assembly change but provide relatively inaccurate test results.