Size Scaling of Tensile Failure Stress in a Soda-Lime-Silicate Float Glass

Abstract

The (tensile) strength-size scaling of a float soda-lime silicate glass was studied using biaxial flexure and Hertzian ring crack initiation testing. The examined Weibull effective areas spanned ~ 0.4 to 48,000 mm2. Both the air- and tin-sides were tested. The air side was stronger than the tin side as others have observed; however, the differences in their characteristic strengths decreased with decreasing effective area, and their strengths converged for effective areas smaller than ~ 100 mm2. The failure stress at the smallest effective area examined for the tin-side was ~ 500% greater than that at the largest effective area while that difference was ~ 250% for the air- side. A Weibull modulus change at ~ 100 mm2 suggests different strength-limiting flaw types were dominant below and above that effective area. These results reinforce the importance to interpret and use tensile strength of glass in context to how much of its area is being tensile stressed.