Simple Method for the Determination of Static or Dynamic Modified J-R Curve

Abstract

Ernst et al proposed a method to calculate the deformation theory J, J_D which takes into account the influence of crack growth on J. Furthermore, Ernst introduced a modified version of the J-integral, J_M, to allow a large relaxation of restrictions on the amount of crack extension and specimen configuration. In this work, simple formulas for the deformation theory J-integral and the modified J-integral are developed. The methods are applied to the static J_IC test and the instrumented Charpy test. The accuracy of the methods in the determination of the J-R curves is discussed, emphasizing the difference between J-R curves for J_D and J_M.