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Measurement of Biaxial Strength of New vs. Used Windshields
Technical Paper
2000-01-2721
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
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! These data demonstrate the need for proper training and careful handling of new windshields to preserve their high initial strength thereby delaying the onset of fracture and ensuring occupants' safety in service.
The edge strength of automotive windshields, measured by vertical bending of uniaxial edge specimens prepared from individual glass plies prior to lamination, is also reported. In view of uniform flaws induced by the edge finishing process the strength distribution is found to be unimodal. The strength data for both the surface and edge regions are then used to estimate the flaw depth which agrees reasonably well with that given by fractographic analysis.
The paper concludes with an assessment of slow crack growth potential in service.
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Authors
Citation
Gulati, S., Helfinstine, J., Roe, T., Khaleel, M. et al., "Measurement of Biaxial Strength of New vs. Used Windshields," SAE Technical Paper 2000-01-2721, 2000, https://doi.org/10.4271/2000-01-2721.Also In
References
- Wood, J. L. et. al. “Contribution of Windshield to Structural Rigidity of Automotive Body,” 2000 IBEC Conference Detroit
- Bartholomew, R. F. Garfinkel, H. M. “Chemical Strengthening of Glass,” Glass Science & Technology 5 Uhlmann Kreidl Academic Press New York 1980
- DIN 52292 “Determination of the Bending Strength Using the Concentric-ring Test and Plate-Shaped Specimens with Large Test Surfaces,” 1984
- Ritter, J. E. et al. “Appraisal of Biaxial Strength Testing,” J. Noncryst. Solids 38 & 39 1980
- Kerper, M. J. Scuderi, T. G. “Modulus of Rupture in Relation to Fracture Pattern,” J. Am. Ceram. Soc. 43 1964
- Levengood, W. C. “Effect of Origin Flaw Characteristics on Glass Strength,” J. App. Physics 29 1958
- Simonen, F.A. et. al. “Probabilistic Failure Prediction for Automotive Windshields Based on Strength and Flaw Distributions,” 2000 IBEC Conference Detroit
- Schmitt, R.W. et. al. “Experimental Stress Analysis of the Concentric Ring Procedure,” SPRECHSAAL 116 1983
- Weibull, W. “A Statistical Distribution Function of Wide Applicability,” J. App. Mech. 18 1951
- Gulati, S. T. “Delayed Cracking in Automotive Windshields,” Proc. 75h Int'l Symp. Nondestr. Charac. Prague 1995
- Vallabhan, C. V. et al. “Stresses in Layered Glass Units and Monolithic Glass Plates,” J. Struc. Engg. 113 1987
- Behr, R. A. et al. “Load Duration and Interlayer Thickness Effects on Laminated Glass,” J. Struc. Engg. 112 1986