Browse Publications Technical Papers 2000-01-2722

Effect of Temperature on Biaxial Strength of Automotive Windshields 2000-01-2722

This paper focuses on the effect of temperature on biaxial strength of curved, symmetrically laminated, automotive windshields. In view of their aspheric curvature, the measurement of biaxial strength requires a special ring-on-ring test fixture with compliant loading and support rings. The key factors that affect strength are (i) fatigue behavior of surface flaws, (ii) expansion mismatch between glass and PVB interlayer, and (iii) interfacial bond integrity. These, in turn, depend on the operating temperature which for automotive windshields can range from −40°C in winter to +50°C in summer.
The data show that the biaxial strength is 21% higher at −40°C and 28% lower at +50°C than that at room temperature. An assessment of fatigue and interfacial bond integrity shows that strength changes of these magnitudes are predominantly caused by residual stresses arising from expansion mismatch between glass and PVB interlayer. The fracture pattern indicates that the bond integrity is excellent over the range of test temperatures. The fatigue resistance of surface flaws, which depends on both the glass composition and molecular activity of water vapor, is considerably lower at +50°C than −40°C and could well account for the high variability in strength data. Such a variability in measured strength can have an adverse effect on the long-term mechanical reliability of windshield. The implication of altered mechanical reliability on occupants' safety is discussed briefly.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 17% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

CAD - Based Synthesis of a Window Lifter Mechanism


View Details


Modeling of In-Cabin Climate and Fogging of Windshield


View Details


Designing Mobile Air–conditioning Systems to Provide Occupant Comfort


View Details