Strength and Static Fatigue of Abraded Glass Under Controlled Ambient Conditions: I, General Concepts and Apparatus

An extensive experimental study of the factors affecting the tensile strength and static fatigue of bulk glass has been conducted. To minimize the effects of past history of the specimens, all specimens were subjected to a controlled, reproducible surface abrasion. Time, temperature, and chemical environment were subject to control and systematic variation during the period from abrasion to test and during the strength test itself. Specimens consisted of flat laths tested in cross bending with the abraded spot in the center of the tension face. An electronically controlled electromagnetic tester permitted applications of pulse loads or constantly increasing loads with controllable durations from about 0.0025 second up to any desired value. The apparatus and methods for producing the abrasions, controlling the environment, and performing the tests are described in this paper. A brief review of the experimental background on the strength of glass is also presented as an introduction to the aims and concepts of this study.