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The automotive industry continues to develop technologies for reducing vehicle fuel consumption. Specifically, vehicle lightweighting is expected to be a key enabler for achieving fleet CO2 reduction targets for 2025 and beyond. Hybrid glass laminates that incorporate fusion draw and ion exchange innovations are thinner and thereby, offer more than 30% weight reduction compared to conventional automotive laminates. These lightweight hybrid laminates provide additional benefits, including improved toughness and superior optics. However, glazing weight reduction leads to an increase in transmission of sound through the laminates for certain frequencies. This paper documents a study that uses a systematic test-based approach to understand the sensitivity of interior vehicle noise behavior to changes in acoustic attenuation driven by installation of lightweight glass.

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.

This paper presents the strength data for conventional automotive windshields in both the new and used conditions. More specifically, the biaxial strength of outer surface of curved and symmetrically laminated windshield, measured in biaxial flexure, is reported. The relative contributions of inplane membrane stress, which can be significant for new windshields, and bending stress are quantified with the aid of strain gauge rosettes mounted on both the outer and inner surfaces of windshield. The strength distribution for new and used windshields, based on Weibull distribution function, is found to be multimodal indicating more than one family of surface flaws. Depending on handling damage during manufacturing, assembly and installation processes, the low strength region of new windshields can approach that of used windshields with 50,000+ road miles!

The adoption of head-up displays (HUDs) is increasing in modern automobiles. Yet integrating this technology into vehicles with standard windshield (WS) laminates can create negative effects for drivers, primarily due to the thickness of glass used. The double ghosting in HUD images is typically overcome by employing a wedged PVB between the two glass plies of the laminate. Another solution is to reduce the thickness of the glass without impacting the overall windshield toughness. Although this still requires the use of a wedged PVB to eliminate HUD ghosting, the thinner glass provides opportunity to increase the image size. However, reducing the thickness of a soda-lime glass (SLG) ply or plies in a conventional soda-lime glass (SLG) laminate can significantly impact the robustness of the laminate to external impact events.

The use of lightweight materials to produce automotive glazing is being pursued by vehicle manufacturers in an effort to improve fuel economy. As glazing’s become thinner, reduced rigidity means that the critical flaw size needed to create fracture becomes much smaller due to increased strain under load or impact. This paper documents experiments focused on the impact performance of several alternative thin laminate constructions under consideration for windshield applications (including conventional annealed soda-lime glass as well as laminates utilizing chemically strengthened glass), for the purpose of identifying new and unique failure modes that result from thickness reduction. Regulatory impact tests and experiments that focused on functional performance of laminates were conducted. Given the increased sensitivity to flaw size for thin laminates, controlled surface damage was introduced to parts prior to conducting the functional performance tests.

Vehicle windshields typically include a black decorative pattern around their periphery and other regions. Examination of field failed parts has shown that windshields often break from impacts in these decoration zones; often with the fracture initiating from the decoration material itself. In this work, the effect of different glazing decoration materials on glass strength and laminate impact resistance was evaluated. The decoration materials investigated included traditional inorganic enamel frit, an organic ink, and a new enamel frit that is compatible with glass chemical strengthening. Ring-on-Ring strength tests were conducted and showed that inorganic enamel frit reduces strength of glass by over 50% compared to undecorated glass, while organic inks do not adversely affect strength. Tests of a newly developed decoration frit material, compatible for chemical strengthening processes, showed strength levels that were on par with undecorated, unstrengthened glass.