An Experimental Examination of Seatbelt Webbing Loading Marks on Automobile Plastic D-Rings

Abstract

This paper documents experimental research determining the belt forces required to create visible and distinct markings on plastic automobile D-rings. The “D-Ring” is the loop through which the shoulder belt feeds before reaching the retractor. In the experimental configuration, ballast is attached to the belt webbing and dropped from a predetermined elevation. By varying the drop height the belt loading characteristics were also changed. Photographs document the resulting loading marks. A Mathematical Dynamic Modeler was used to calculate the Rigid Body Dynamic models to determine occupant belt loads from 5th and 50th percentile Hybrid III anthropomorphic test devices under various crash pulse conditions. These values were correlated to the experimental research. Conclusions are made relating D-ring markings to the delta-V of an automotive accident.