LOW VELOCITY IMPACTS AND TEMPERATURE SENSITIVITY OF AUTOMOTIVE WINDSHIELDS

Abstract

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 0.03 AND 0.037 IN THICKNESS HPR NTERLAYERS. A SIMULATED DASHBOARD IS INCLUDED IN TEN DUMMY-WINDSHIELD IMPACT TESTS. EXTENSIVE HPR INTERLAYER RUPTURE OCCURS AT 30 AND 110 F, PRODUCING GREATER LACERATION HAZARD. /SAE/