Probabilistic Strength Estimation for Brittle Materials under Variable Loading Rate
Shinya MATSUDA, Keiji OGI and Ryosuke WATANABE
Abstract:This paper presents a theoretical approach for estimating the fracture strength of brittle materials under variable loads. First, a model was established on the basis of the slow crack growth concept in conjunction with two-parameter Weibull distribution for a brittle material subjected to variable loads. Assuming fracture of a brittle material under constant load, a fracture criterion obtained from the model was related with the empirical life law. Next, four-point bending test was carried out for soda glass under two step crosshead speeds. The experiment result was compared with the predictions to verify the validity of the model. Key Words:Brittle material, Variable loading rate, Equivalent time, Equivalent fracture strength, Slow crack growth, Unified nonlinear cumulative damage law