Full scale laboratory studies using curved laminated safety glass windshields, a horizontal accelerator, and a 50th percentile dummy to provide impact performance are presented. Lacerative damage based on moist chamois face covering and Severity Indices for annealed glass windshield configurations were obtained on the current domestic automobile windshield, experimental thin annealed glass windshields in symmetrical and asymmetrical glass configurations, and windshields with 0.045 in. HPR interlayer.
Symmetrical thin glass windshields, such as, 0.050 in glass, gave excellent performance to 38 mph. Lacerative damage decreases as the inboard glass thickness decreases for windshields having 0.030 in. HPR interlayer and 1/8 in. float glass outboard ply. Windshields with 0.045 in. HPR interlayer, designed to improve penetration resistance, have somewhat higher Severity Indices. Such windshields will require further study.