Capabilities of a New Specimen Type for Determining the Static Fracture Toughness

The diversity of modern structural glasses is immense, and their mechanical properties vary significantly. Reliable evaluation of glass fracture toughness enables the rational design of structural elements, accurate prediction of their service life, and guaranteed operational safety. This study introduces a novel specimen configuration for determining the static fracture toughness of glass. The specimen design incorporates a stabilizing zone, which reduces its sensitivity to loading device stiffness and ensures straight crack propagation. Specimen preparation is simple and requires no specialized, expensive equipment. Utilizing this approach, static fracture toughness testing of glass can be performed on a standard tensile testing machine. This specimen configuration enables the analysis of crack deceleration and arrest stages. At these stages, the crack tip is fully formed, and the crack front exhibits a natural, rectilinear profile. Consequently, the quality of initial crack preparation in the specimen becomes non-critical. The application of numerical simulation in experimental data processing yielded the dependence of the critical stress intensity factor on the crack propagation velocity. The developed specimen was successfully tested on silicate glass. The advantages of the proposed approach are demonstrated by comparing the results with data obtained using a traditional compact tension specimen.