1971-02-01

Low Velocity Impacts and Temperature Sensitivity of Automotive Windshields 710869

Headform impacts at 5.5-7.7 mph using the 22 lb air-stabilized missile were run on glass panels that did not fracture to measure deceleration pulses and obtain Severity Index (SI) values. These tests show low SI values for this range of impact velocities. Dummy-windshield tests were run at speeds of 8.7-21.9 mph to measure SI and laceration. In all cases laceration is low and SI values do not indicate concussive hazard below approximately 15 mph impact velocity even when the glass does not fracture. These data are of particular interest for those accident situations below the probable velocity for deployment of a passive restraint such as the air bag.
The currently used HPR interlayer for automotive windshields shows excellent safety performance at room temperature but is less effective at other temperatures. Impact studies of several glass structures at 30-110 F are presented for 0.030 and 0.037 in. thickness HPR interlayers. A simulated dashboard is included in the dummy-windshield impact tests. Extensive HPR interlayer rupture occurs at 30 and 110 F, producing greater laceration hazard. These data indicate that an improvement in temperature performance is desirable providing other safety performance characteristics are retained.
THE AUTOMOBILE WINDSHIELD continues to be of concern in the vehicle design for motorist safety in crashes. While a new and significantly improved safety windshield was introduced with our domestic 1966 model vehicles, the search continues to expand our performance data and identify modifications that overcome the deficiencies of this improved windshield. This report covers data on impact performance to 35 mph for flat panels using the 5 lb steel ball and 22 lb headform and windshields using a 50th percentile anthropomorphic dummy over the 30-110 F temperature range.

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