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

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 ∼0.4-48,000mm². 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 a decreasing effective area, and their strengths converged for effective areas smaller than ∼100mm². 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 ∼100mm² suggests different strength-limiting flaw types were dominant below and above this effective area. These results reinforce the importance of the interpretation and use of the tensile strength of glass in context to how much of its area is being subjected to tensile stress.