An experimental program was conducted which demonstrated that a 2-ply windshield could be constructed with impact performance, as measured in the laboratory, comparable to that of standard 3-ply HPR windshields with inner Shield and Securiflex laceration shield treatments.
The 2-ply windshield construction chosen for testing contained an outer ply of float glass and an inner multilayer laceration shield. This laceration shield is comprised of a polyvinyl butyral interlayer (0.95 mm thick), a polyester “laceration shield” (0.13 mm thick), and a proprietary abrasion-resistant coating (these three materials being produced by Du Pont).
Full-scale sled tests were performed of the 2-ply construction using unrestrained Hybrid III dummies at the Safety Research and Development Laboratory (SRDL), GM Milford Proving Ground. These tests, which provided a “realistic” evaluation of windshield performance in frontal impacts showed that the 2-ply windshield is a viable concept in terms of occupant safety. For a 3.18-0.95-0.13 mm 2-ply construction, frontal impact performance (as measured in terms of facial laceration, penetration resistance, and occupant injury indices, including HIC) was found to be comparable to that of 2.29-0.95-2.29 mm 3-ply windshields with Inner Shield and Securiflex laceration shield treatments.
It is important to note, however, that important technical issues such as mounting system, noise transmission, and vehicle structural response need to be addressed prior to considering this experimental 2-ply construction for production field usage.