Stability of crack propagation during bending tests on brittle materials

Abstract

Applications of ceramic materials usually involve thermal stresses that can reduce their lifetime considerably. One of the most relevant mechanical properties for evaluating thermal shock damage resistance is the energy of fracture. In order to obtain this property, a stable crack growth regimen must be achieved throughout the test. In this paper, three-point bending tests are analyzed to determine how machine stiffness influences load point displacement rates. Understanding the differences between recorded and adjusted displacement rates is important in determining the stability of crack growth. This statement is corroborated by experimental data on sintered high-alumina, low-cement refractory castables.