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Das Ziel der Untersuchung war, die Grenzen der Belastbarkeit eines Rollstuhl- und Personenrückhaltesystems mit Kraftknoten nach DIN 75078-2 zu ermitteln. Dazu wurden dynamische Schlittenversuche durchgeführt, bei denen die Verzögerungspulse sowie das Gesamtgewicht von Rollstuhl und Prüfpuppe variiert wurden. Für die Untersuchungen kamen ein Prüfrollstuhl, definiert nach ISO 10542, und Rückhaltesysteme mit Kraftknoten gemäß DIN 75078-2 zum Einsatz. Das Rückhaltesystem bestand aus einem Rollstuhl- und einem Personenrückhaltesystem, wobei das Rollstuhlrückhaltesystem (RRS) mit vier bzw. sechs Gurten und entsprechenden Retraktoren an einem dynamischen Schlittenaufbau befestigt wurde. Das Personenrückhaltesystem (PRS) bestand aus einem am Rollstuhl integrierten Beckengurt sowie einem Schulterschräggurt, der am Beckengurt und am Schlittenaufbau befestigt wurde. Ferner wurden bei den Versuchen Prüfpuppen verschiedener Alters- und Gewichtsklassen (P6, HIII 5 %, HIII 50 % und HIII 95 %) eingesetzt Die Belastungsanforderungen für das Rückhaltesystem wurden sukzessiv erweitert, indem einerseits das Gesamtgewicht (Rollstuhl und Prüfpuppe) und andererseits auch die Verzögerungspulse bis zur Versagensgrenze erhöht wurden. Das Vier-Gurt-Rückhaltesystem konnte bei einem Verzögerungspuls von 10 g einem Gesamtgewicht von bis zu 221 kg standhalten. Bei einem Verzögerungspuls von 20 g und einem Gesamtgewicht von 134 kg wurde das Vier-Gurt-System bis über die Grenzen belastet. Das Sechs-Gurt-Rückhaltesystem hat Belastungen bis 221 kg standgehalten. Infolgedessen ist bei einer Erhöhung der Verzögerungspulse auf 20 g und einem Gesamtgewicht von mehr als 109 kg ein Sechs-Gurt-System zu empfehlen.
Rollovers continue to be a major source of heavy truck fatalities when compared to other accident modes. Real world rollover accidents are analyzed and two distinct damage patterns are identified. Damage to heavy truck roofs can occur from lateral loading that transitions to vertical roof loading as the vehicle rolls onto its side and then over onto its roof. A second load path can occur when the vehicle has rolled onto its side and furrows into the ground generating large longitudinal friction forces between the roof and ground. A review of the previous literature and various test methodologies are presented. A sled impact test methodology is presented which allows for structural assessment of a heavy truck cab's crashworthiness in both of these loading environments. Two test series are presented using the sled impact test methodology in order to analyze real world truck rollovers using varying impact platen and contact angles. The structural deformation and failure patterns were found to be consistent with damage seen in real world accident vehicles. In each case, a second equivalent truck cab was then reinforced and tested under similar conditions to evaluate the energy management and crush resistance of a stronger cab structure. These structural reinforcements demonstrated a substantial reduction in roof crush and protected the survival space of the occupant compartment. The sled impact test procedure is an effective method for testing the structural performance of a heavy truck cab in a variety of loading scenarios comparable to real world accidents and ascertaining the load and energy load levels in these accident modes.
The United Nations Economic Commission for Europe Informal Group on GTR No. 7 Phase 2 are working to define a build level for the BioRID II rear impact (whiplash) crash test dummy that ensures repeatable and reproducible performance in a test procedure that has been proposed for future legislation. This includes the specification of dummy hardware, as well as the development of comprehensive certification procedures for the dummy. This study evaluated whether the dummy build level and certification procedures deliver the desired level of repeatability and reproducibility. A custom-designed laboratory seat was made using the seat base, back, and head restraint from a production car seat to ensure a representative interface with the dummy. The seat back was reinforced for use in multiple tests and the recliner mechanism was replaced by an external spring-damper mechanism. A total of 65 tests were performed with 6 BioRID IIg dummies using the draft GTR No.7 sled pulse and seating procedure. All dummies were subject to the build, maintenance, and certification procedures defined by the Informal Group. The test condition was highly repeatable, with a very repeatable pulse, a well-controlled seat back response, and minimal observed degradation of seat foams. The results showed qualitatively reasonable repeatability and reproducibility for the upper torso and head accelerations, as well as for T1 Fx and upper neck Fx. However, reproducibility was not acceptable for T1 and upper neck Fz or for T1 and upper neck My. The Informal Group has not selected injury or seat assessment criteria for use with BioRID II, so it is not known whether these channels would be used in the regulation. However, the ramping-up behavior of the dummy showed poor reproducibility, which would be expected to affect the reproducibility of dummy measurements in general. Pelvis and spine characteristics were found to significantly influence the dummy measurements for which poor reproducibility was observed. It was also observed that the primary neck response in these tests was flexion, not extension. This correlates well with recent findings from Japan and the United States showing a correlation between neck flexion and injury in accident replication simulations and postmortem human subjects (PMHS) studies, respectively. The present certification tests may not adequately control front cervical spine bumper characteristics, which are important for neck flexion response. The certification sled test also does not include the pelvis and so cannot be used to control pelvis response and does not substantially load the lumbar bumpers and so does not control these parts of the dummy. The stiffness of all spine bumpers and of the pelvis flesh should be much more tightly controlled. It is recommended that a method for certifying the front cervical bumpers should be developed. Recommendations are also made for tighter tolerance on the input parameters for the existing certification tests.