Measurement of Biaxial Strength of Laminated Windshields

Biaxial strength of laminated safety windshields was measured by testing 200mm x 200mm square specimens, prepared from automotive windsheilds, in a specially designed ring-on-ring test fixture to facilitate good seating on loading and support rings. These tests were carried out over a wide range of temperature (?40'C to 50'C) to simulate realistic driving conditons. The tensile strength of the outer surface (#1 surface) was the primary focus of this study since it is exposed to both stone impact and frictive damage during vehicle driving. The strength measurements for (i) new, (ii) used, and (iii) impact damaged windshields are reported. The data show that compressive stresses induced by PVB interlayer increase the biaxial strength significantly at ?40'C while creep deformation of PVB interlayer at 50'C reduces the biaxial strength relative to that at room temperature. The data also show that handling, assembly, shipping, and installation induced damage during manufacturing also reduces the strength significantly. These findings are useful for designing lightweight laminated windshields without compromising the safety of occupants.

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The Authors

Mr. Suresh Gulati Research Fellow/Consultant Corning Incorporated Dr. Gulati obtained his B.S. degree in mechanical engineering from University of Bombay (India), M.S. degree from Illinois Institute of Technology (Chicago, USA), and Ph.D degree in Applied Mechanics... Read more