THE RELATION BETWEEN J_D AND J_M FOR THE CENTRE CRACKED TENSION SPECIMEN GEOMETRY

摘要

The paper determines the difference between the modified J integral (J_M) and deformation J integral (J_D) crack growth behaviours as obtained from load, load-point displacement and crack extension measurements using a centre cracked panel subjected to plane stress tensile loading conditions. Theoretical analyses show that the J_M crack growth resistance curve lies above the J_D curve for a short crack, whereas the reverse is true for a long crack. However, for a material with a reasonably high crack growth resistance, the ratio of the slopes of the J_M and J_D curves is close to unity.