Investigations on the Tensile Strength of Glass

JSGT 1932 V16 T145-T170

 The description is given of an apparatus used to determine the tensile strength of glass specimens of approximately 1 mm diameter, the specimens having constrictions at their centres. These constrictions were formed in an electrically heated tube at a determined temperature. It was found that the type of fracture obtained, the thickness of the specimen, acid polishing the specimens and matt etching the specimens considerably affected the tensile strength values, but that the influence of different loading methods, the temperature of constriction formation, the presence of strain, and the influence of sulphurous fumes during annealing were very small, if existent. Experiments were made to attempt to correlate tensile strength and thermal endurance results. The conclusion was drawn that the presence of surface flaws in glassware, as proposed by A. A. Griffith, would explain the results obtained.

E. J. Gooding