Does the cyclic J-integral ΔJ describe the crack-tip opening displacement in the presence of crack closure?

In this paper, the correlation of the cyclic J-integral, Delta J, and the cyclic crack-tip opening displacement, Delta CTOD, is studied in the presence of crack closure to assess the question if Delta J describes the crack-tip opening displacement in this case. To this end, a method is developed to evaluate Delta J numerically within finite-element calculations. The method is validated for an elastic-plastic material that exhibits Masing behavior. Different strain ranges and strain ratios are considered under fully plastic cyclic conditions including crack closure. It is shown that the cyclic J-integral is the parameter to determine the cyclic crack-tip opening displacement even in cases where crack closure is present. (C) 2014 Elsevier Ltd. All rights reserved.