Research of CRS side impact test procedures using an acceleration type sled system

Tanaka, Yoshinori; Hosokawa, Naruyuki; Yamaguchi, Daisuke; Matsui, Yasuhiro

Affiliations

¹National Traffic Safety and Environment Laboratory, Japan

Abstract

Accident data show that the injury risks to children seated in child restraint systems (CRSs) are higher in side collisions than those in any other types of collisions. Accordingly, NHTSA [1] reported about CRS side impact test methods. In WG29/GRSP, the ISOFIX type CRS new regulation [2] was accepted at the 2011 December GRSP. Adding side impact sled test is one of the topics for a new regulation.

In Europe, the deceleration type sled system is most commonly available, and consequently most studies regarding CRS side impact tests are done by the deceleration type sled system. But NTSEL, the type approval test department in Japan, has an acceleration type sled system, so it is necessary to confirm that the CRS side impact test procedure of new regulation can be tested by the acceleration type sled test system.

In this present research, NTSEL conducted CRS side impact sled test series for evaluating the CRS side impact test procedure by using an acceleration type sled system. The test methods using our acceleration type sled system are almost same as those published in NHTSA’s 2009 ESV technical paper [1]. The tests series we conducted are as follows: (1) We conducted tests to confirm that the test conditions of new regulation can be satisfied by an acceleration type sled system. (2) We conducted tests to confirm that the severities of the CRS side impact test used by the deceleration sled and the acceleration sled are similar or not. (3) We conducted tests to confirm whether there are any problems with the specified CRS side impact test procedures or not.

(1) The CRS side impact test conditions specified by the new regulation were defined to be the relative velocity and the intrusion between the door and seat. We confirmed that the tests using an acceleration type sled system could satisfy the relative velocity corridor and intrusion as proposed in new regulation.

(2) Test data measured by the deceleration type sled systems from European test laboratories were obtained in order to compare the severities between the different types of sled systems. We then compared the 2 different CRSs test data. As for the dummy injury measures, the coefficients of variation were less than 10% with the exception of that for the neck. As a result, the severities of the CRS side impact tests conducted using a deceleration sled and an acceleration sled were determined to be similar.

(3) We confirmed the main test parameters which determine dummy injury measures to evaluate whether test conditions of the new regulation were specific enough or not for evaluating the CRS performance. So we conducted tests under 2 different conditions which both satisfy the test conditions of new regulation (i.e., the relative velocity and intrusion between the door and seat), and we collected the different dummy injury measures. These test data indicated that additional conditions are needed for the CRS side impact test procedure of the new regulation to make the conditions the same in various tests. We studied the parameters which influenced the dummy injury measures. We confirmed that the relative velocity between the door and dummy had a large influence on the dummy injury measures. Therefore, we propose to add the door velocity condition to the CRS side impact test procedure.

Links

URL: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv23/23ESV-000335.pdf

Cited Works (3)

Year	Entry
2011	Johannsen H, Bendjellal F, Renaudin F, Claeson P. Update on lateral impact test procedure for child restraint systems. In: Proceedings of the 22nd International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 13-16, 2011; Washington, DC.
2011	Yoshida R, Okada H, Nomura M, Yokohashi M, Fujii C, Mizuno K, Yonezawa H, Tanaka Y, Hosokawa N, Matsui Y. Identification of head injury mechanisms of a child occupant in a child restraint system based on side impact tests. In: Proceedings of the 22nd International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 13-16, 2011; Washington, DC.
2009	Sullivan LK, Louden AE. NHTSA’s initial evaluation of child side impact test procedures. In: Proceedings of the 21st International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 15-18, 2009; Stuttgart, Germany.