Windshield Impact Response: An Empirical Study of the Standard Three-Ply Construction

An experimental program to characterize the impact response of a standard 3-ply high penetration resistance (HPR) windshield was conducted using a specially designed linear impactor test facility (1). * Parameters varied included the location and angle of impact, impactor mass and velocity, windshield bonding system, and windshield integrity (whether it was pre-cracked). Specific findings included the following:

• The magnitude of the initial spike in the force-time history is a function of the inertia of the windshield mass localized around the impact site.
• The windshield bond has no effect on this initial force spike and thus cannot be used to alter or control it.
• Minor pre-cracking of the windshield has no effect on the impact event.
• The impact severity decreases as the rake angle (mounting angle with respect to the vertical) increases.
• The location of the initial impact site has only a minor effect on the impact severity.
• The coefficient for the ploughing component of head-windshield friction is approximately 1 independent of the test conditions.