Fracture Assessment of U-notches under Mode I Loading by means of Critical Value of the J-integral.

Abstract: In this paper, two practical linear-elastic equations for the evaluation of the critical value of the J-integral in plates with U-notches under Mode I loading are presented and applied to brittle and quasi-brittle materials. It is found that these two proposed equations provide the same results with differences being negligible. By using one of these equations one can evaluate the J_cr and then predict the critical fracture load by means of the J_cr criterion. The results show that the material control radius to the notch root radius ratio (R_c/ρ), and the Poisson''s ratio affect the critical value of the J-integral (J_cr) in U-notches under Mode I loading, and other parameters may be negligible. The predicted fracture loads are compared with experimental results. Two different materials are considered in the tests: a composite material (Al-15%SiC) tested at room temperature and a steel with a ferritic-pearlitic structure tested at −40°C. [Copyright &y& Elsevier]