Fracture of Tempered Glass



    1. Glass Research Center, Pittsburgh Plate Glass Company, Pittsburgh, Pennsylvania 15238
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      Now research engineer, Applied Research Laboratory, United States Steel Corporation, Monroeville, Pennsylvania 15146.

  • Presented at the Sixty-Ninth Annual Meeting, The American Ceramic Society, New York, N. y., May 2, 1967 (Glass Division, NO. 20–G-67).

  • At the time this work was done, the writer was senior research engineer, Glass Research Center, Pittsburgh Plate Glass Company.


The fracture of thermally tempered glass is discussed in terms Of both the stored elastic strain energy in the glass due to tempering and the elastic energy release rate Of crack extension, 9. The latter is used to obtain an analytical correlation between the maximum tensile stress and the average particle size at time of fracture. The theoretical predictions are supported by experimental data obtained for various glass thicknesses and temper levels.