Glass Thickness and Fragmentation Behavior in Stressed Glasses

Hoikwan Lee, Seoyeong Cho, Kyungmin Yoon, Jaeho Lee

Glass Tech Research Center, Samsung Corning Precision Materials, Asan, Korea.

DOI: 10.4236/njgc.2012.24020                

Abstract

Breakage patterns, residual stress, and fractured surfaces on tempered glasses are investigated to find the correlation among glass thickness, tempered level, and the number of fragments, particularly when the glass thickness is less than 4 mm. Relatively thin glasses require high compressive stress for producing fragments, and the required compressive stress is increased with decreasing glass thickness (3.2 to 2.1 mm). By analyzing the residual stress of glasses before and after the fragmentation test, we observe that a relatively thin glass spends more stored energy to generate a new fracture surface and stores less energy for the second cracking as compared to thick glasses. Fractography shows that all glasses have a similar characterization on the fractured surface irrespective of glass thickness. However, the only dif- ference is the depth of the compressive layer. By reducing the depth of the compressive layer to less than approx. 20% of the glass thickness, it is observed that the possibility of producing small fragments is dramatically decreased. There- fore, this study confirms that the compressive stress and its depth are essential as key factors contributing to the achievement of a relatively high fragmentation using a thin glass.

Keywords

Fragmentation; Breakage Pattern; Residual Stress; Thin Tempered Glass; Fractured Surface

Conflicts of Interest

The authors declare no conflicts of interest.

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